Riverbend DS Assocation Home Page » Resources » Patents » Prenatal Screening » Diagnostic Test for Prenatal Identification of DS...
 Diagnostic Test for Prenatal Identification of Down's Syndrome and Mental Retardation and Gene Therapy

Inventors: Smith; Desmond J. (Oakland, CA); Rubin; Edward M. (Berkeley, CA)
Assignee: The Regents of the University of California (Oakland, CA)
Appl. No.: 071074
Filed: April 30, 1998 		  Primary Examiner: LeGuyader; John L.
Assistant Examiner: Kaushal; Sumesh
Attorney, Agent or Firm: Mahoney; John W., Aston; David J., Martin; Paul R.
United States Patent 6,100,033 August 8, 2000

Abstract
A diagnostic test useful for prenatal identification of Down syndrome and mental retardation. A method for gene therapy for correction and treatment of Down syndrome. DYRK gene involved in the ability to learn. A method for diagnosing Down's syndrome and mental retardation and an assay therefor. A pharmaceutical composition for treatment of Down's syndrome mental retardation.

Goverment Interests
Reference to Government Interest
This invention was made in the course of contract DE-AC03-76SF0098 between the United States Department of Energy and the University of California for the operation of Lawrence Berkeley Laboratory. The United States Government has certain rights to this invention.

Parent Case Text
This application claims priority to a Provisonal Application Ser. No. 60/045,604, filed May 5, 1997.

Claims
What is claimed is:

  1. In a method for prenatal testing of a child, the improvement comprising testing for Down syndrome, comprising the steps of:
    1. preparing nucleic acid probes which hybridize to the human DYRK gene;
    2. labeling said probes so as to make their presence in a cell detectable;
    3. obtaining cells from said child;
    4. exposing said cells to said probes; and
    5. detecting specific binding of three probes in a single nucleus of a cell.
  2. The method of claim 1 wherein the probe is radiolabelled, immunolabelled or labeled with fluorescence.
Description
Backgroud of the Invention

1. Field Of the Invention

This invention concerns a diagnostic test useful for prenatal identification of Down syndrome and mental retardation and a gene therapy for correction and treatment thereof. In particular, this invention concerns identification of DYRK gene involved in the ability to learn. The invention further concerns a method for diagnosing Down's syndrome and mental retardation and an assay therefor, a method for gene therapy of Down's syndrome and a pharmaceutical composition for treatment of Down's syndrome mental retardation.

2. Background Art and Related Disclosures

Down syndrome occurs in about one out of every 800 newborns, with the incidence increasing markedly in the offspring of women over 35. Affecting an estimated one million Americans, it is the leading genetic cause of mental retardation and is associated with a shorter than average life expectancy. Other symptoms are heart and intestinal defects, problems with the immune and endocrine systems, and raft of tissue and skeletal deformities.

Individuals with Down syndrome carry a complete extra copy of chromosome 21 in all of their cells, giving each cell a total of 47 chromosomes rather than the normal 46. For this reason, the condition is also known as "Trisomy 21". There are, however, rare forms of Down syndrome in which only part of chromosome 21 is present in triplicate.

The existence of these rare forms of Down syndrome suggests that the condition may be due to a limited number of genes and led to development of the current invention and to creation of a special series of transgenic mice containing different adjacent segments of human chromosome 21.

Up to date, there is no available treatment of the Down's syndrome mental retardation and learning disability and for correction of this genetic defect.

Recently, with the advent of biotechnology, more and more genetic tools have been developed leading to a new way of treatment of the genetic diseases by gene therapy. To this end, complex trait analysis is assuming increasing importance in understanding mammalian biology. New mapping reagents, such as polymorphic markers distributed throughout the genome described in Nature, 380: 152 (1996) and Prog. Clin. Biol. Res., 384:1 (1993), have assisted in the quantitation of the number of genes contributing to such traits and in their localization. Despite these advances, the multi-factorial nature of these traits means that ultimate identification of the responsible genes will be extremely difficult.

Down syndrome can be regarded as a complex trait, as it is likely that numerous genes contribute to the phenotype (PNAS (USA), 91:4997 (1994)). The syndrome results in a variety of distinct phenotypes (PNAS (USA), 86:5958 (1989) and importantly, is the leading genetic cause of mental retardation in humans, with over 1 million affected in the United States.

Although controversial, there is evidence that an extra dose of one region of chromosome 21 at 21q22.2 may be particularly important in the pathogenesis of the syndrome (ibid). These studies, together with analogous investigations employing mice described in Nature Genet., 11:177 (1995), indicate that the 21q22.2 region, or the region of mouse chromosome 16 syntenic with human chromosome 21, contains genes that affect learning and memory when their dose is increased by a modest amount. These analyses, however, fail to map individual loci contributing to the behavioral abnormalities.

As an approach to fine mapping and identification of loci from 21q22.2 region contributing to learning impairment and behavior observed with Down syndrome when present in an extra dose, the current invention describes multiple lines of transgenic mice containing several contiguous YACs from 21q22.2. This panel of low copy number YAC transgenic is referred to as an in vivo library, because in total a significant segment of about 4% of human chromosome 21 is propagated in vivo, using the mouse as a host and Identifying the genetic material by testing the mouse learning ability and behavior. Using this in vivo library, loci affecting learning and memory from the 21q22.2 region of the human genome could thus be identified in phenotypic screens employing functional assays for behavior.

It is, therefore, a primary objective of this invention to identify loci from chromosome 21q22.2, responsible for Down syndrome, using the Down syndrome as a model for complex trait analysis and utilizing this identification for diagnostic and therapeutic purposes. It is also another objective to determine under which conditions an extra dose of loci from chromosome 21q22.2, when present, contribute to learning abnormalities.

All patents, patent applications and manuscript disclosed in this specification are hereby incorporated by reference.

SUMMARY
One aspect of the current invention concerns a method for prenatal diagnosing and identification of Down syndrome.

Another aspect of the current invention concerns identification of DYRK gene responsible for Down syndrome and involved in the ability to learn.

Still another aspect of the current invention concerns an assay for early prenatal detection of the genetic defect known as Down syndrome and/or mental retardation.

Still yet another aspect of the current invention concerns a gene therapy for corrections of Down syndrome.

Still another aspect of the current invention concerns a generation of transgenic mice bearing a variety of yeast artificial chromosomes gene (YACs).

Still another aspect of the current invention concerns a generation of in vivo library of multiple lines of transgenic mice containing several contiguous YACs from 21q22.2 chromosome.

Still yet another aspect of the current invention concerns primers used for synthesis of complementary DNA of various regions of the DYRK gene.

Still yet another aspect of the current invention concerns primers used for synthesis of complementary DNA of specifically identified locus of chromosome 21 which is responsible for the genetic defect and mutation observed in Down syndrome.

Still yet another aspect of the current invention concerns a cDNA complementary to chromosome 21 locus responsible for Down syndrome.

Still another aspect of the current invention concerns identification of the wild type of chromosome 21 locus corresponding to the locus responsible for Down syndrome and using this wild type DNA to replace the mutated chromosome 21 locus responsible for Down syndrome.

Still yet another aspect of the current invention concerns a method for gene therapy wherein the wild type DNA is delivered into the DYRK gene and replaces the mutated sequence causing Down syndrome.

Still yet another aspect of the current invention concerns radiolabelled probes used for detection of the presence of the complementary sequence by molecular hybridization.
Source: http://www.uspto.gov/patft/
Revised: February 3, 2001.