Free Spoken Presentations April 6-7, 2001 Barcelona, Spain

Textos cedidos por la: Fundació Catalana Síndorme de Down, Katy Trias Trueta, Directora General c/ València, 229, pral. 1ª, 08007 Barcelona, España +34 93 215 74 23. Fax: +34 93 215 76 99 E-mail: integra@fcsd.org

Margareta Mikkelsen, Henrik Hasle ,Inge Haunstrup Clemmensen

John F. Kennedy Institute, Department of Medical Genetics 7, Gl. Landevej , 2600 Glostrup, Denmark

Department of Paediatrics, Aarhus University Hospital Skejby, Aarhus

Institute of Cancer Epidemiology, Danish Cancer Society, Copenhagen

The study is based on a register study of 2814 individuals with Down syndrome, 1536 males and 1278 females. They were all studied cytogenetically and registered in the Danish Cytogenetic Register. Follow-up data were obtained for the entire cohort. Cancers were identified by linkage to the Danish Cancer Registry. The number of person years at risk was 48 453. Standardised incidence ratio and 95% CI were calculated.

The study confirmed the very high risk of leukaemia in early childhood. Leukaemia was diagnosed in36 persons with 2 expected, 98% in children below the age of 15. The cumulative risk of leukaemia was 2.1 by the age of 5 years and 2.7 by the age of 30 years.

Only 24 solid tumours were observed with 47.8 expected. Especially noteworthy was the absence of breast cancer in women, whereas 7.3 cases were expected. A higher than expected number of cases of testicular, ovarian cancer and retinoblastoma was found, however not significant.

The distinctive patterns of malignancies in Down syndrome provide clues in the search for leukaemic genes and tumour suppressor genes. 

ABNORMAL RARITY AND UNUSUAL DISTRIBUTION OF BRAIN NEOPLASMS IN DOWN SYNDROME. ANALYSIS OF FRENCH MORTALITY DATA AND LITERATURE REVIEW.

Daniel Satgé ¹, Annie J. Sasco ²

1 Laboratoire d'anatomie pathologique, Centre hospitalier, Tulle, France

2 Unit of epidemiology for Cancer Prevention, International Agency for Research on Cancer.

and INSERM, Lyon, France

Brain tumors have not yet been specifically studied in large-scale populations of Down syndrome (DS) patients. We therefore decided to conduct a national mortality study in France. We analyzed an age and periodic-specific causes of death in DS and in the general French population during the years 1971-1994 using the national mortality statistics from de INSERM. We found no death ascribed to brain tumors among the DS deaths up to the age of 15, whereas 4.1 were expected based on national rates (p from Poisson test = 0.017). For all ages, we found 9 brain tumor deaths versus 34.1 expected (p = 0.0000003).

This under-representation is in agreement with two recent Danish (Hasle et al, 2000) and Japanese (Nishi et al, 2000) epidemiological studies showing a decreased mortality from brain neoplasm in DS (respectively 1 versus 3.3 expected and 0 versus 4.3 expected).

Similarly, an extensive review of the literature could find only 36 primary brain neoplasms in patients with DS. The histological distribution was unusual with an excess of germ cell tumors (39 % versus < 3 % expected), of mesenchymal tumors (11 % versus < 1 % expected) and a complete lack of embryonal neural neoplasms. Altogether, these data suggest that brain tumors could be about 3 times less frequent in DS than in the general population, probably in part because of a lack of embryonnal neural neoplasms, in agreement with the currently proposed tumor profile in DS (Satgé et al, 1998). It is also worth noting that brain metastases of solid cancers have not been reported in DS either. We suspect the role of tumor suppressor genes on chromosome 21 and particularly for embryonnal neural neoplasms, the role of an overexpression of the gene S100 beta.

Grants from the Ligue Nationale contre le Cancer, comité de la Corrèze and the Fondation Jérôme Lejeune supported this study.

ASSESSMENT OF THE UTILIZATION AND SENSIBILITY OF THE DOWN SYNDROME SCREENING AND DIAGNOSIS METHODS IN 4 SPANISH POPULATIONS

Joaquín Salvador¹, Sixto García-Miñaur², Neus Baena³ and Fernando Ariza⁴

1. Registre de Defectes Congènits de la ciutat de Barcelona (REDCB)

2. Registro de Anomalías Congénitas de la Comunidad Autónoma Vasca (RACAV)

3. Registre de Defectes Congènits del Vallès (RDCV)

4. Registro de Defectos Congénitos de Asturias (RDCA)

Down syndrome is the most frequent chromosomal anomaly at birth. Prenatal diagnosis is possible by mean of a fetal karyotype, but the risk of miscarriage of the invasive procedures, their cost and some organizational problems prevent its utilization over the whole population. Pregnant women are screened in order to establish high-risk groups to who offer these procedures. The screening tests are based in maternal age, ultrasound markers, and biochemical parameters in maternal serum.

Using the Down syndrome cases collected by the 4 population-based birth defects registries in Spain (Asturias, Barcelona, El Vallès and País Vasco), we measure the use of the different screening methods, their sensibility, the use of invasive procedures and the cases induced for abortion in the 4 areas during the period 1996-1998.

Obstetrical ultrasound is generalized over the surveyed populations. Barcelona has higher figures in the rest of indicators, i.e. use of biochemical screening and both ultrasound and biochemical sensibility. An increasing ultrasound sensibility over the years is observed when the 4 areas are grouped.

The proportion of cases with invasive procedure is, logically, higher in Barcelona. All cases prenatally diagnosed in the 4 areas (but one) have been induced for abortion.

CLINICAL OVERVIEW ON A DOWN'S SYNDROME POPULATION IN VALENCIA (SPAIN)

Fernández-Delgado R, Plaza A, Puertos D, Martí E, Rosado I, Benavent R, García R, Blasco C, Beltrán M, Andrés AM and García J. Down's Syndrome Unit. Department of Pediatrics. University of Valencia.

Departamento de Pediatría. Hospital Clínico Universitario. Avda. Blasco Ibáñez 17. 46010. Valencia. ESPAÑA.

In the last 8 years, we have seen 550 individuals with Down's syndrome, in the setting of a Down's Syndrome medical multidisciplinary group.

The majority were infants, children and adolescents. The gender distribution showed 41% males and 59% females. Most of them have been visited several times (1 to 8). The median age of parents was 33.02±6.13 years for mothers and 34.59±6.4 for fathers. The most frequent karyotype was regular trisomy, but we found 2.7% mosaicisms and 3.8% translocations. Only a few progenitors had undergone karyotype, which was abnormal in 0.3% of cases. There were no events in pregnancy and labour. 60.3% of newborns were admitted, mainly due to cardiopathy, congenital malformations, hyperbilirrubinemia, and others The most important medical complaints recorded were: pulmonary (bronchitis, asthma and pneumonia), cardiac (septal defects), digestive (constipation, celiac disease), endocrinologic (hypothyroidism), orthopedic (foot abnormalities), dermatologic (folliculitis) and others. At each visit a physical examination was performed and weight and height were recorded. The most important topics of health care were discussed with the family. The majority of children were examined for anemia and basic nutritional study, immunitary status and thyroid hormones. The correctable defects were treated adequately.

FOLLOW-UP OF THE THYROID FUNCTION IN A POPULATION

Markus Kaski, Maija Wilska

Rinnekoti Foundation, Espoo, Finland

The aim of this longitudinal population study was to create a feasible screening program for thyroid dysfunction among the Down population in Finland.

The study population and design. In the northern provinces of Oulu and Lapland there were 539 persons with Down syndrome in 1994. Assaying the TSH was performed in 395 (73.2%) individuals, aged 1-65 yrs through their local public health clinics. If TSH was >6 mmol/l, TSH and free T4 were taken in 10-12 months. If it was >10 mmol/l, the control was done in 2-3 months. In 1997 there was another control of TSH and fT4 with thyroid peroxidase antibody (TPO-ab) when possible. The turn-out was 240 persons.

Results. Seventeen individuals were previously on thyroxin medication.Altogether 23 new cases of hypothyroidism were found, the prevalence increasing with age. The total in Oulu was 5.8% vs.18.4% in Lapland. Half of the cases with subclinical hypothyroidism (TSH high, fT4 normal) had resolved spontaneously during the follow-up.Three persons were previously on medication for hyperthyroidism. Eight new cases were found.

The follow-up of the cases with initially high TSH as well as the distribution of TPO-ab among hypo-subclinical-and hyperthyroidisms will be presented. On the basis of the findings we also have a proposal for screening program.

RELATION OF ZINC, TSH AND GLIADIN ANTIBODIES IN PATIENTS WITH DOWN SYNDROME. PRELIMINARY RESULTS.

Wolfgang Storm

St. Vincenz-Krankenhaus, Kinderklinik

Husener Str. 81, D - 33098 Paderborn, Germany

There is an increased incidence of hypothyroidism, zinc deficiency and celiac disease in patients with Down syndrome. In order to determine if there is a correlation or dependency between these three findings we measured zinc, TSH and gliadin antibodies (IgG and IgA) in 61 children with Down syndrome. IgG gliadin antibodies were increased in 50 (82%), IgA antibodies in 17 (28%) patients. TSH was increased in 12 (20%), plasma zinc was decreased in 15 (25%) children. These incidences are all beyond those in the general population. Although cross-sectional data only show clear correlations between an increased TSH, increased gliadin antibodies and low levels of plasma zinc in 9 (15%) patients, longitudinal follow-ups revealed both hypothyroidism , zinc deficiency and celiac disease in at least four patients.

According to our preliminary results we suggest (latent) celiac disease as the basic disorder of zinc deficiency and probably (subclinical) hypothyroidism with the potential of developing manifest celiac disease and hypothyroidism, respectively, in patients with Down syndrome.

RESEARCH ON A GROUP OF 265 DOWN SYNDROME CHILDREN MOST OF WHICH HAD CONGENITAL HEART DISEASE, IN TWO DIFFERENT REFERRAL HOSPITALS.

I.Bendayán ¹, J.Casaldàliga ², M.Fuster ¹, C.Sanchez ², J.Girona ², A.Gonçalves ³.

1. Pediatric Cardiology. Hospital Clínico de Santiago de Compostela. 2. Pediatric Cardiology . Hospital Materno Infantil del Valle de Hebrón de Barcelona. 3. Pediatric Cardiac Surgery. Hospital Materno Infantil del Valle de Hebrón de Barcelona.

265 children with Down syndrome were admitted to Hospital occasionally between 1993 and 2000, most of which 202/265 ( 76% ) had heart disease .

The study has analysed different parameters as prenatal diagnosis, surgery outcome, mobility or mortality, but we have emphasised on heart disease and pulmonary hypertension.

108/202 ( 53,4% ) had atrioventricular septal defects, among them 84/108 were complete defects, 5/108 were intermediate defects and 19/108 were partial defects ( atrial septal defects ostium primum with or without mitral regurgitation ). 62/202 ( 30,8% ) had other septal defects, among them 50/62 were ventricular and 12/62 were atrial septal defects. 15/202 ( 7,5% ) had isolated patent ductus arteriosus. 10/202 ( 4,9% ) had isolated tetralogy of Fallot. 7/202 ( 3,4% ) had other heart diseases.

12/265 ( 4,5% ) had isolated patent foramen oval without clinical significance and was not considered as heart disease.

Pulmonary hypertension was found in 55/202 ( 27,3% ), usually detected before surgery. 33/55 were complete atrioventricular septal defects, 3/55 were transitional atrioventricular septal defects, 17/55 were ventricular septal defects ( 9/17 with associated patent ductus ), 1/55 was an atrial septal defect and 1/55 was an isolated patent ductus arteriosus.

Conclusion: In this study, the overall classification of cardiovascular defects in Down children is similar to others investigations. Early hypertension is still a challenge whether by physicians or by researchers. In this study, high incidence of unnoticed patent ductus has been found in association with septal defects and pulmonary hypertension.

OTOLARYNGOLOGIC MANIFESTATIONS IN DOWN SYNDROME - A 5 YEAR STUDY

Sally R. Shott, M.D and Aileen Joseph, B.S.

Otolaryngologic problems are frequently seen in children with Down syndrome (DS). This includes chronic ear infections and hearing loss, chronic rhinitis and sinusitis, and upper airway obstruction and sleep abnormalities. In February 1999, a 5 year study, following the ear, nose, and throat problems seen in children with Down syndrome began at the Children's Hospital in Cincinnati, Ohio. The purpose of this study is to develop a data base while providing the current 'state of the art' treatment, both medical and surgical, for the otolaryngologic manifestations of DS. By starting with only very young children, we hope to eliminate any secondary consequences that may occur from these conditions not being treated appropriately.

The need for such a study comes from the belief that much of the current data is retrospective and uncontrolled. We hope to establish more accurate 'norms' and elevate the expectations of what this group of children can achieve. Too often in the past, the otolaryngologic problems were accepted as simply "part of the DS" and not aggressively addressed.

There are currently 60 children enrolled. This presentation will review the study design as well as present preliminary data from the first 2 years of the study.

INFLUENCE OF VISUAL FEEDBACK INFORMATION ON A SEQUENCING TASK IN ADULTS WITH DOWN SYNDROME

Naznin Virji-Babul, ^1,2 Jennifer E.V. Lloyd, ¹ and Geraldine Van Gyn¹

1School of Physical Education, University of Victoria, Victoria B.C. Canada ²Down Syndrome Research Foundation, Vancouver, B.C. Canada

Max. 200 words; The purpose of this study was to investigate the influence of visual feedback information on the acquisition of a sequencing task in adults with Down Syndrome (DS). 10 adults with DS and 14 normal adults performed a button pressing task in a specific sequence under the following conditions: Full visual feedback (FVF)- button board fully visible with full view of their arm/hand. No visual feedback (NVF)- buttons on the board were visible and no visual feedback of their arm/hand. Hand feedback (HF) - buttons on the board visible and vision of the hand only. We compared mean speed of movement (MT) and mean reaction times (RT) between groups and across the 3 conditions. Interestingly, while no differences were observed in RT, significant differences were observed in MT in adults with DS across conditions. Movements were slowest in the NVF condition. HF decreased MT and FVF resulted in the shortest MT. Further analysis indicated that adults with DS who had a range of previous movement experiences performed similarly to the normal adults. These findings suggest that adults with DS rely on visual feedback when performing sequences of movement and practice in different environmental contexts may help to improve motor performance.

PLASMA AMYLOID BETA PROTEIN 1-42 (Aß42) LEVELS ARE INCREASED IN OLD DOWN SYNDROME (DS) BUT NOT IN YOUNG DS

P.D. Mehta, A.J. Dalton, S.P. Mehta, and B.A. Patrick.

NY. State Institute for Basic Research in Developmental Disabilities, Staten Island, NY 10314.

All adults with DS have neuropathological changes characteristic of Alzheimer disease (AD) by 40 years of age. Soluble forms of Aß generated from amyloid precursor protein commonly end at C-terminal residue 40 or 42. The possession of two variants of ApoE,4 allele is a significant risk factor for the development of AD. Our objective was to quantitate the levels of Aß40 and Aß42 in plasma from young DS (<40 years of age), old DS (>40 years) and age-matched normal controls, and analyze the relationships with apolipoprotein E (ApoE) phenotype. Blood was collected from 28 young DS (mean age ± SD years; 30 ± 6) (5 with ApoE,4 allele and 23 without), 28 aged-matched controls (7 with ApoE,4 allele and 21 without), 32 old DS (51 ± 7 years) (9 with ApoE,4 allele and 23 without) and 32 age-matched controls (10 with ApoE,4 allele and 22 without). Aß 40 levels were higher in young DS than controls (p<.0001). Aß42 levels in young DS and controls were similar. Aß40 and Aß42 levels were higher in old DS than controls (p<.001). There was no relationship between Aß levels with ApoE,4 allele in DS and controls. Plasma Aß42 is increased in old DS concurrently with the development of AD neuropathology.

ALOPECIA AREATA IN CHILDREN WITH DOWN SYNDROME

Wolfgang Storm M.D.

St. Vincenz-Krankenhaus, Husener Str. 81, 33098 Paderborn, Alemania

Alopecia areata is a complication in children with Down syndrome being observed with a higher incidence than in the general population. Some of the resumed etiologies are vitamine A and zinc deficiency and hypothyroidism, but most of the cases are considered to be an autoimmune disorder. Among the 731 patients of our Preventive Medicine Clinic for children with Down Syndrome (children up to the age of 18 years) 17 (2,3%) had episodes of alopecia areata. Causative factors could be found in two (sequelae of the treatment of lymphoblastic leukemia and celiac disease, respectively), in 15 patients there were no apparent etiologic mechanisms. Nevertheless, 13 children were successfully treated (1 with celiac disease by a gluten free diet and 12 by homeopathic treatment).

SLEEP ABNORMALITIES IN CHILDREN WITH DOWN SYNDROME: EVALUATION AND TREATMENT

Sally R. Shott, M.D

Children's Hospital Medical Center- 3333 Burnet Avenue- Cincinnati, Ohio 45229

Children with Down syndrome (DS) are known to be at higher risk for developing symptoms of obstructive sleep apnea (OSA). In the normal pediatric population, obstructive sleep apnea is most commonly due to tonsil and adenoid (T&A) hypertrophy and resolves after these tissues are removed. In the DS population, however, there are multiple factors that contribute to airway obstruction including medial displaced tonsils, midface and mandibular hypoplasia, generalized hypotonia with obstruction in the oropharynx and hypopharynx, macroglossia with a tendency of the tongue to fall posteriorly, and an increase in the incidence of upper airway secretions and infections. Tonsillectomy does not always resolve the obstruction.

In this presentation, the sleep studies on 25 children with DS are reviewed. Specific abnormalities are examined including obstructive apneas, hypopneas, central and mixed apneas, hypoventilation, sleep staging and arousal indexes. Parents are questioned about their child's sleep behavior and responses correlated to study results.

In addition, limitations of treatment options are discussed. Preliminary data from 4 patients treated with radiofrequency reduction to the base of the tongue are also presented.

DEVELOPMENT OF A QUANTITATIVE MEASURE OF HYPOTONIA FOR INDIVIDUALS WITH DS

Naznin Virji-Babul ^1,2 and Meggan Hunt ¹

1 School of Physical Education, University of Victoria, Victoria B.C. Canada

2 Down Syndrome Research Foundation, Vancouver, B.C. Canada

The overall purpose of this study is to develop a quantitative measure of hypotonia that can be used to evaluate movement dysfunction in individuals with Down Syndrome (DS).

Design/Methods: Three individuals with DS and three individuals with normal tone took part in this preliminary study. EMGs were recorded during passive, isometric and isokinetic knee extension movements. A Cybex II dynamometer was used to control the speed of active movements (30^o/sec and 120^o/sec). Passive knee extension movements were performed under the same movement speeds.

Results: In individuals without DS, the duration of the agonist burst decreased as movement speed increased. In contrast, individuals with DS showed little change in agonist burst duration with changes in movement speed. During isometric contractions, the amplitude of the agonist burst was lower than in individuals with normal tone and was characterized by multiple bursts of activity. The magnitude of peak torque at both movements speeds was also much less in DS than in individuals with normal tone.

Conclusion: Hypotonia appears to be associated with difficulty in modulating agonist burst duration with changes in movement speed and difficulty in sustaining isometric muscle contractions. Future studies will focus on analysis of EMG activity during functional movements.

PROSPECTIVE EVALUATION OF ESOPHAGEAL MOTOR DYSFUNCTION IN DOWN'S SYNDROME

N. Zárate, F. Mearin, A. Hidalgo*, J-R Malagelada

Digestive System Research Unit and Radiology Department*, Fundació Catalana Síndrome de Down. Hospital General Vall d'Hebrón. Barcelona. Spain.

We recently published an association between achalasia and Down's syndrome in 5 patients (Am J Gastroenterol 1999; 94:1674-7). Based on this, we hypothesized that Down's syndrome might imply a predisposition to esophageal dysmotility

AIM: To determine the prevalence and way of presentation of esophageal motor dysfunction in a non-selected population of subjects with Down's syndrome.

METHODS: 58 Down's syndrome patients and 38 healthy controls were evaluated. A global symptom score and individual scores for dysphagia for liquids and solids, heartburn, vomiting/regurgitation were obtained. Esophageal function was evaluated initially by scintigraphy using liquid and semisolid bolus. According to both scintigraphy and clinical evaluation results, participants underwent a radiological and manometric study.

RESULTS: The most frequent symptoms were: dysphagia for liquids (n=9) and dysphagia for solids (n=10). Liquid and semisolid retention of the tracer was significantly higher in patients than in controls (p<0.05). No correlation was found between symptoms and esophageal retention. Five of the fifteen esophagograms performed were abnormal. Manometry showed achalasia in two subjects, total body aperistalsis in one and non-specific esophageal motor disorder in two.

CONCLUSION: Esophageal motor disorders, particularly achalasia, are frequent in individuals with Down's syndrome. Awareness of esophageal dysmotility in this population is important to avoid potential complications.

Key words: Down's syndrome, achalasia, esophageal dysmotility, scintigraphy.

AMETROPIA AND STRABISMUS IN DOWN SYNDROME.

Puig J., Galán A., Díaz J., Fernández E.

Avda. del Jordán 31, 10° 4ª. 08035. Barcelona. Spain.

Purpose: To analise the characteristics of ametropia and strabismus in children with Down syndrome.

Methods: A complete ophthalmological examination has been carried out in 546 children with Down syndrome (295males and 251 females).

Results: We have found strabismus in 240 children (44%): horizontal deviations in 196 children (35,89%) and vertical strabismus in 6 children (1,09%). The other 38 children (6,9%) had both vertical and horizontal deviations. Esotropia of variable angle has been the most frequent finding in our study. In this group of patients the most frequent ametropia was hyperopia, but myopia was more frequent than in normal children.

Conclusions: Ametropia and strabismus in Down syndrome are differrent in frequency, type, low incidence of amblyopia and causes of torticollis.

ORAL PATHOLOGY IN DOWN'S SYNDROME CHILDREN.

Sánchez-Varela A, Tobella Camps L, Casal Sánchez, C.

Department of Dentistry and Orthodontics of Sant Joan de Dèu Hospital. Spain

Objetive: Knowing the clinical requirements in dentistry and orthodontics in Down's syndrome in children.

Design: clinic retrospective.

Place: Department of Dentistry and Orthodontics of Sant Joan de Dèu Hospital.

Patients: 197 children; 121 females and 76 males. Mean age at firt visit: 6.6 years.

Method: clinical records of all Down's syndrome patients visited in our departament from 1987 to 2000, using a protocol to valorate the number and visits rate, pathology and performed treatments.

Results: -visit rate: total visits: 1442; orthodontics:318 and pediatric dentistry:1124.

79% of visits in pediatric dentistry are observations and 21% are dentistry treatments.

-pathology: agenesis (85%):upper lateral incisors (29%),upper second premolars(22%), lower second premolars(15%) and lower lateral incisors(13%); malocclusion (27%); dental caries (27%); gingivitis (23%); ectopic teeth(10%); bruxisme (7%); periodontal disease (2%)

-treatments: outpatients with local anesthesia: same frecuency for conservative treatment than for extraction treatment(48%), inpatients with general

anesthesia: conservative treatment(61%) and extraction treatment(32%).

orthodontics: 9% children, being successful in just 4%.

Conclusions:

-We agree with other studies about the percentage of caries,however the percentage of agenesias is higher than them.

-Our frecuency of visits(6 to 12 months)is higher than the one recommended in the Down's syndrome universal protocol which is matter of reflexion.

-We are careful to indicate orthodontic treatments.

CORRELATION ULTRASONOGRAPHIC AND PATHOLOGIC FINDINGS IN CASES OF TRISOMY 21

Giler O, Bendayan I, Carreras Elena, Girona J, Casaldáliga J, Cabero Ll.

Unit of Ecografic and Pediatric Hospitals Vall d'Hebrón Autonomous University of Barcelona Spain.

OBJECTIVE

We studied 157 patient that was attended in our units of Diagnostic Prenatal since 1995 to 1999 diagnosed of

fetus with Down Syndrome.

MATERIAL AND METHODS

The ILEs they were carried out among the 14 and 22 weeks of pregnancy. Of these, 131 cases had ultrasonography prior to ILE and the subsequent pathology report conclusions was included in the study.

RESULTS

Ultrasonography was presented an only marker in a 53%, and more than one marker in the 46%, in relation to the malformations, only one in 54% and one more malformation in 45%. The pathology report was presented a single marker in 19% and more than one in the 81% of the cases, in the malformations only one 86% and more than one in 14%. At the level of cardiopatics the most frequent by ultrasonography and by pathology report the presence of canal auriculoventricular in 44% and 40% respectively. The correlation among the ultrasonographics images and the pathology findings is very narrow, except in the images of FOCI, that not they are visualized at the level of the piece to investigate.

CONCLUSIONS

Therefore, the ultrasonography permits us to visualize markers and malformations suspicious of Trisomy 21, but the pathologies finds confirm the diagnosis.

HOMOEOPATHIC TREATMENT OF CHILDREN WITH DOWN SYNDROME

Wolfgang Storm M.D.

St. Vincenz-Krankenhaus, Husener Str. 81, 33098 Paderborn, Alemania

In addition to some predominantly allopathically treatable complications there are a lot of daily medical problems in children with Down Syndrome obliging to frequent visits to a physician. These usually are no life threatening complications, but nevertheless contributing to their quality of life. Six case reports are to show the successful treatment with homoeopathic remedies in children with Down Syndrome

.

SIZE OF EXTERNAL AUDITORY CANAL IN DOWN'S SYNDROME: RELATIONSHIP WITH EUSTACHIAN TUBE PERMEABILITY

J.Domènech, M. Carulla

Fundació Catalana Síndrome de Down - University of Barcelona - Hospital Clínic - Barcelona, Spain

Children with Down's Syndrome usually show narrow external auditory canals. The relationship between this narrowing and the patency of the Eustachian tube has been studied. Six hundred and twenty-four children were studied. External auditory canal size was found to be normal in 30,4% of the studied cases. There was a statistically significant relationship between normally sized canals and good permeability of the Eustachian tube, which means that children with wide auditory canals are less prone to develop secretory otitis media. Other parameters (such as nasal obstruction and nasal discharge) were also studied but significance was marginal.

RECOMBINATION ACROSS 21CEN AND CHROMOSOMAL NON-DISJUNCTION: CHARACTERISATION OF NEW POLYMORPHIC MARKERS ON THE SHORT ARM OF CHROMOSOME 21.

Buard J, Laurent AM and Roizès G

Séquences Répétées et Centromères Humains- Institut de Génétique Humaine - CNRS UPR 1142

141 rue de la Cardonille - 34396 Montpellier cedex - France

Non-disjunction (NDJ) of chromosomes 21 during maternal meiosis is the major cause of trisomy 21. Altered recombination is the only known molecular correlate of NDJ, with half NDJ events being achiasmate and most remaining events presenting atypical location of recombination exchanges across the long arm of chromosome 21. In particular, an excess of peri-centromeric exchanges for meiosis II NDJ events has been evidenced using the most proximal polymorphic DNA markers available.

We have sought to characterise more proximal markers on the long arm together with proximal markers of the short arm of chromosome 21 in order (i) to measure recombination frequencies across 21cen for normally disjoined chromosomes and for non-disjoined chromosomes , (ii) to determine unambiguously the meiotic stage of non-disjunction and (iii) to precise the relative importance of juxta-centromeric recombination in non-disjunction. Juxtacentromeric regions of chromosome 21 consist in a patchwork of intra- and inter-chromosomal genomic duplications, mainly present on other peri-centromeric regions of acrocentric chromosomes. Polymorphic markers embedded in these regions are therefore found in several copies in the genome.

We will report our strategy and our progresses for the characterisation of unique polymorphic markers in these regions and our preliminary analysis of recombination activity across 21cen.

CALCIPRESSIN 1 IS REGULATED AT THE TRANSCRIPTIONAL AND POST-TRANSLATIONAL LEVELS BY CALCINEURIN

L. Genescà, S. de la Luna, J. Fuentes, X. Estivill, M. Pérez-Riba.

Down syndrome Research Group, Medical and Molecular Genetics Center, IRO,

Hospital Duran i Reynals, Avia. de Castelldefels Km 2.7, L'Hospitalet de Llobregat,

08907-Barcelona, Spain

Calcipressin 1, encoded by the chromosome 21 gene DSCR1, is a calcineurin binding protein that belongs to the calcipressin family along with ZAKI-4 and DSCR1L2. Calcipressin 1 binds to calcineurin A, the catalytic subunit of the Ca2+/calmodulin dependent protein phosphatase PP2B, in a calcium independent way. The binding results in the inhibition of this enzyme.

It has been previously described that dephosphorylation by calcineurin of specific conserved serine residues in the SP motives of the NFAT family members is responsible for their nuclear translocation. A similar SP consensus motif is present in all the members of the calcipressin family. In this sense, we have found that calcipressin 1 is a phosphoprotein. By mutation of the two serines of the SP motif we can predict that at least one of the two serines is phosphorylated. Finally, we have found that calcipressin 1 is also a substrate for calcineurin phosphatase activity.

Since we have shown that calcineurin is also responsible for transcriptional activation of DSCR1, we can conclude that calcipressin 1 is regulated at two different levels by calcineurin, at the transcriptional and at the post-translational levels.

DSCR1 is overexpressed in Down syndrome fetal brain. Althought DS is a multifactorial disease, the role of the calcipresin 1 as an inhibitor of calcineurin signaling could provide new insights towards the possible involvement of this signaling pathway in the pathology of Down Syndrome.

Supported by: the European Union (BIOMED2 BMH4-CT98-3039), the Spanish CICYT (SAF99-0092-CO2-01), and the Fundació Catalana Síndrome de Down/Marató de TV3-1993

DYRK1A (HUMAN MINIBRAIN) INTERACTS WITH 14-3-3

Mónica Álvarez, Xavier Altafaj, Xavier Estivill and Susana de la Luna

Down syndrome Research Group, Medical and Molecular Genetics Center, IRO,

Hospital Duran i Reynals, Avia. de Castelldefels Km 2.7, L'Hospitalet de Llobregat,

08907-Barcelona, Spain

DYRK1A (MNBH) is a gene located on human chromosome 21q22.2. The enzymatic activity of the encoded protein product, DYRK1A, has been demonstrated in its ortologue Dyrk1A in rat: it is a dual specificity protein kinase, able to phosphorylate serine/threonine and tyrosine residues. However, the participation of DYRK1A or other DYRK-related kinases in a particular signal transduction pathway has not been yet elucidated. We have used the human full-length DYRK1A cDNA as a bait in the yeast two-hybrid system to screen a human fetal brain cDNA library. One of the interacting clones was found to encode the protein 14-3-3

b . The 14-3-3 proteins are a family of intracellular, dimeric, phosphoserine-binding molecules expressed in all eukaryotic cells that play important roles in a wide range of vital regulatory processes, such as mitogenic signal transduction, apoptotic cell death, and cell cycle control. We have generated deletion mutants of DYRK1A and determined the binding site for 14-3-3.Co-transfection of COS-1 cells with DYRK1A and 14-3-3 have shown co-localization of both proteins in DYRK1A characteristic nuclear speckles and in plasmatic membrane ruffles. Co-expression of DYRK1A and a dominant negative form of 14-3-3 has revealed an increased accumulation of DYRK1A,suggesting that 14-3-3 could be involved in the regulation of the half-life of DYRK1A.

Supported by: the European Union (BIOMED2 BMH4-CT98-3039), the Spanish CICYT (SAF99-0092-CO2-01), and the Fundació Catalana Síndrome de Down/Marató de TV3-1993

ENRICHED ENVIRONMENT AND BEHAVIOURAL PERFORMANCE OF TS65DN MICE, A MODEL FOR A DOWN SYNDROME: GENDER DIFFERENCES.

C. Martínez-Cué¹, C. Baamonde¹, M.A. Lumbreras¹, J. Paz¹, M.T. Davisson², M. Dierssen³, J. Flórez¹.

1. Dept. Physiol. Pharmacol., Univ. Cantabria, Santander, Spain.
2. The Jackson Laboratory, Bar Harbor, Me 04609, USA.
3. Cent. Med. Molec. Genetics, L'Hospitalet de Llobregat, Barcelona, Spain.

We have assessed the effects of enriched environment (EE) upon behavioral and cognitive performances of partially trisomic Ts65Dn (TS) mice and their control (C) littermates. EE was applied to pups for 7 weeks after weaning. Circadian spontaneous activity (actimetry), exploratory behavior (hole board), total activity in the open field, passive avoidance behavior, and spatial memory (Morris water maze, repeated acquisition paradigm) were analyzed in 86 female and 75 male mice, starting 15 days after completing EE. For each gender, mice were distributed in non-EE and EE of C and TS groups. EE partially reduced in TS females and enhanced in TS males the circadian spontaneous activity. Exploratory behavior was increased by EE in all groups regardless of gender or presence of trisomy. Passive avoidance was modified by EE only in females, C and TS. In the Morris water maze, a significant improvement of the spatial memory was observed in EE-C female but not in EE-C male mice, as assessed by measurements of escape latencies and distances traveled. Performances in the 4 groups of C animals were also consistently and significantly better than those of the matching groups of TS mice. EE induced a significant improvement of performance in TS female animals. In contrast, EE deteriorated performance in TS male mice. In all groups, changes in escape latencies and distances induced by EE were accounted for by changes in the total time spent in the periphery of the pool. It is concluded that EE may induce behavioral and learning changes in the TS mice, although the gender is a factor that play a modulatory role in the influence of EE. (Supported by Foundation 'Marcelino Botín', Real Patronato Atención Minusvalías, and SAF99-0092-C02-02).

PHENOTYPIC CHARACTERIZATION OF A KNOCKOUT MOUSE MODEL FOR THE DYRK1A/MNBH GENE

aV. Fotaki, ^aM. Dierssen, S. ^bAlcántara, ^aC. Casas, ^cS. Martínez, ^bE. Soriano, ^aX. Estivill, ^aM.L. Arbonés

aDown Syndrome Research Group, Medical and Molecular Genetics Center, IRO, Avia de Castelldefels, km. 2.7, L' Hospitalet de Llobregat, 08907 Barcelona, ^bDepartment of Cell Biology and Neurosciences Research Center (CERN), Faculty of Biology, University of Barcelona, Barcelona, ^cDepartment of Morphological Sciences, Faculty of Medicine, University of Murcia, Murcia

The human homologue (DYRK1A/MNBH) of the Drosophila minibrain (mnb) gene maps on 21q22.2. The mnb gene appears to play an essential role during postembryonic neurogenesis in regulating the number of distinct types of neuronal cells in Drosophila. In order to elucidate the functional role of the minibrain protein in mammals we have generated a knockout mouse for the Dyrk1A/Mnbh gene. These mice (Mnbh-/-) are not viable and die between days 10 and 12 of embryonic development. Mice carrying a targeted disrupted allele (Mnbh±) are viable and fertile. However, these mice are smaller in size than their wild type siblings and are born in a lower percentage than the expected one. Behavioral analyses indicate that the preweaning Mnbh± mice present a developmental delay. Histological analyses show a reduction in the brain size of the Mnbh± mice and minor differences in its general cytoarchitecture compared to their wild type littermates. These results indicate that the Dyrk1A/Mnbh gene acts in a dose-dependent manner. The lack of one copy of the gene causes an abnormal phenotype while the lack of two copies causes embryonic lethality.

LEARNING DEFICITS AND MOTOR ABNORMALITIES IN THE TGDYRK1A MICE: A MURINE MODEL OF DOWN SYNDROME

X. Altafaj¹, M. Dierssen¹, C. Baamonde², J. Visa¹, M. Oset¹, J. Guimerà¹, J. Flórez², C.Fillat¹, X. Estivill¹. ¹

Grup Recerca Síndrome de Down, Centre de Genètica Mèdica i Molecular, IRO-Hosp. Duran i Reynals, Barcelona, Catalunya, ²Dept. Fisiología y Farmacología, Univ. Cantabria, Santander, Cantàbria

The DYRK1A gene, the human homologue of the Drosophila minibrain gene, is located in the Down syndrome (DS) critical region. The alterations present in mutant minibrain flies such as learning deficits and hipoactivy suggest that this gene may participate in some of the neurological alterations present in DS. To elucidate this hypothesis, we have generated transgenic mice overexpressing the cDNA encoding for Dyrk1A/Mnbh under the control of the inducible sMT-I promoter. Expression of the transgene is ubiquitous and the levels of Dyrk1A/Mnbh mimic the overexpression found in DS. During neurodevelopment transgenic mice showed a persistence of immature locomotor patterns, delayed neuromotor development and an altered motor coordination, which was maintained during adulthood. Hyperactivity and reduced emotionality were observed in the open field and in the plus maze tests. In the Morris water maze TgDyrK1A mice showed a significant increase in the average distance travelled in the acquisition sessions. This increased latency is related to reference memory, with intact working memory. These alterations clearly indicate that DYRK1A overexpression might participate in the neurodevelopment delay and learning deficits of DS.

Supported by: FCSD, CEC/BIOMED2 GENE-CT96-0054 FIS 00/0795 SAF-99-0092 PM95-0106-C02 ERBFMBICT972278. X.A. is a fellow of FCSD

MITOCHONDRIAL DNA MUTATIONS IN DOWN'S SYNDROME.

Svetlana Arbuzova¹, Giovanna De Benedictis², Giuseppina Rose², Tim Hutchin³, Howard Cuckle³. 

Medico-Genetic Centre, Donetsk, Ukraine¹; University of Calabria, Italy²; University of Leeds, UK³

Wide variation in onset and severity of dementia in Down's syndrome (DS) individuals suggests other factors besides the genes on chromosome 21 are involved in the syndrome's pathogenesis. We hypothesize the role of mtDNA mutations in the development of DS.

Mutations of mtDNA have been associated with Alzheimer's disease, diabetes, hypothyroidism, aging, and so could explain the connection of such conditions with DS. The presence of mtDNA mutations can explain the reason for free radical damage in DS which is unlikely to be a consequence of the SOD-1 gene effect. We obtained data about a significant decrease of SOD-1 activity, but increase of lipid peroxidation, with increasing age in DS patients.

To test our hypothesis we have sequenced the entire mtDNA from 3 DS persons (age 11, 26 and 40 years) from the Ukraine. A high incidence of mtDNA mutations was found including ones not previously described:

47,XY,+21			47,XY,+21			46,XY,t (14;21)
Base change	Gene	Amino acid	Base change	Gene	Amino acid	Base change	Gene	Amino acid
G2702C	16SrRNA	-	C3990T	ND1	syn	C5187T	ND2	syn
C5024T	ND2	syn	T4454C	tRNAmet	-	G6261A	CO I	A→T
T14924C	Cytb	S→P	C7794T	CO II	A→V	C7873T	CO II	syn
			G8616T	ATPase6	L→F	C10822T	ND4	syn
			G9053A	ATPase6	S→N	A10972G	ND4	syn
			A13780G	ND5	I→V	A14977G	Cytb	syn

Further studies are required to determine if mtDNA mutations are indeed risk factors for DS.

2-D GEL ANALYSES OF PROTEIN PATTERNS IN DOWN VS CONTROL FOETAL BRAIN SAMPLES AND IN CULTURED CELLS EXPRESSING USP25 (21q11.2).

Cols N, ValeroR, Oppermann M, González-Angulo O, Marfany G. & Gonzàlez-Duarte R.

Dept. Genètica. Facultat de Biologia. Universitat de Barcelona

Avda. Diagonal 645, 08028, Barcelona. Spain

The molecular bases of the complex DS phenotype are still unclear. Altered expression of many genes, other than those located on chromosome 21, could explain many of the common traits associated to this syndrome. To approach differential gene expression in Down and control foetal brain samples, we have performed 2-D (two dimensional) gel electrophoreses, combined with mass mapping and database searches. In addition, we have used this powerful technique to evaluate the dosage effect of individual chrom. 21 genes in cell cultures. This type of analysis allowed the identification of 40 proteins, most of them present in both, control and Down brain samples and represented different types of proteins. Moreover, an increased proteolysis in the syndrome samples could be detected.

We had previously identified USP25 on 21q11.2, a gene involved in the ubiquitin-dependent protein degradation pathway. To elucidate the pressumptive USP25 dosage effect on intracellular protein turnover, SH-SY5Y neuroblastoma cells are presently being transfected and analyzed by 2-D gel electrophoresis.

BRAIN ADENYLYL CYCLASE AND PHOSPHOLIPASE C SIGNALING PATHWAYS IN ALZHEIMER'S DISEASE AND DOWN SYNDROME.

M.A. Lumbreras¹, C. Baamonde¹, G. Lubec², N. Cairns³, C. Martínez-Cué¹, M. Dierssen⁴, J. Salles⁵, J. Flórez¹.

1. Dept. Physiol. Pharmacol., Univ. Cantabria, Santander, Sapin.
2. Dep. Pediatrics, Univ. Vienna, Austria.
3. Inst. Psychiat. King's College, London, U.K.
4. Cent. Med. Molec. Genetics, L'Hospitalet de Llobregat, Barcelona, Spain.
5. Dep. Pharmacol., Univ. País Vasco, Vitoria, Spain.

We have reported abnormal patterns in the functioning of adenylyl cyclase (AC) and phospholipase C (PLC) in several brain areas of the Down syndrome (DS) mouse model Ts65Dn. The present experiments were aimed at further explore the AC and PLC signaling pathways in brain membrane preparations obtained from cerebral cortex and cerebellum of adults with DS, compared to control adults and adults with Alzheimer's disease (AD). AC signaling was assessed by determining cAMP formation in isolated membranes under basal conditions and after stimulation with GTP

g S (10

m M), norepinephrine (NE, 100

m M), SKF38393 (SKF, 100

m M), and forskolin (FK, 100

m M). PLC was assessed by analyzing the breakdown of [³H]PIP₂ into [³H]inositol phosphates under basal conditions and after stimulation with GTP

g S (3

m M), 5-methyltryptamine (300

m M), carbachol (1 mM), and calcium (10

m M). In cerebral cortex, cAMP production was reduced in DS and AD compared to control brains under basal conditions, after stimulation with GTP

g S, NE, SKF, and FK. No differences between DS, AD and control were observed in PLC activity under basal and GTP

g S and Ca-stimulated conditions The response of DS brains to serotonergic and cholinergic stimulations was significantly depressed, and that of AD brains was only to cholinergic stimulation. In cerebellum, cAMP production was reduced in DS and AD compared to control brains under basal conditions, after stimulation with GTP

g S, NE, SKF, and FK. PLC activity was reduced in DS cerebellum compared to control and AD brains under basal conditions and after stimulation with GTP

g S, serotonergic and cholinergic agonists. The response of DS and AD cerebellum to Ca-stimulation was significantly depressed. It is concluded that AC and PLC signaling pathways are severely disturbed in the brain of DS adults, to a greater extent and in a differential manner than in AD brain. (Supported by: Grants SAF99-0092-C02-02, FIS 00/0795, and M. Botín and M. Valdecilla Foundations).

NEW TOOLS FOR THE STUDY OF THE TRANSCRIPTOME OF HUMAN CHROMOSOME 21 GENES IN DOWN SYNDROME

P. Kahlem, S. Schrinner, S. Hennig, H. Lehrach, M-L Yaspo

Max Planck Institute for Molecular Genetics, Ihnestrasse 73, D-14195 Berlin, Germany.

With a median incidence rate of 1:1000 live births, Down syndrome (DS) is the most frequent viable chromosomal aberration syndrome and genetic cause of mental retardation in the human population. Despite numerous molecular and genetic studies aimed at establishing phenotype-genotype correlations, the molecular and biochemical mechanisms underlying DS pathogenesis are still unknown. Novel strategies are needed for investigating the molecular etiology of DS. The knowledge of chromosome 21 gene catalog now allows to construct chr.21 specific cDNA arrays as a means to analyze the impact of gene imbalance on the full transcriptome of chromosome 21. A total of 351 expressed sequence tags (ESTs) were selected from the dbEST public database, representing 187 of the 224 chromosome 21 genes. Six additional transcripts were cloned by RT-PCR and we are currently attempting the cloning of remaining gene predictions on chr.21. We are using this cDNA resource for spotting nylon membranes and glass chips, as tools for exploring variations of gene expression profiles in trisomic cells. The hybridization-based scheme and bioinformatics components will be presented and preliminary data will be discussed.