SCA7 gene and methods of use
The present invention provides diagnostic methods of identifying individuals at risk and not at risk of developing spinocerebellar ataxia type 7. The present invention also provides for methods for identifying expanded repeats, and the DNA flanking the expanded repeats, from genomic DNA.
1. A method of determining the presence or absence of a polymorphic CAG trinucleotide repeat in a human patient comprising determining the presence of a polymorphic CAG trinucleotide repeat in a CAG repeat region of a spinocerebellar ataxia, type 7 gene in a nucleic acid sample from said patient, and determining the size of the polymorphic CAG trinucleotide repeat wherein the presence of a polymorphic CAG trinucleotide repeat is determined by amplification of nucleic acid containing the CAG trinucleotide repeat using a pair of oligonucleotide primers which specifically amplify the region of nucleic acid containing the expanded CAG trinucleotide repeat, and detecting amplified products containing the CAG trinucleotide repeat region, wherein the oligonucleotide primers comprise SEQ ID NO:5 and SEQ ID NO:6.
2. A method for determining whether a human is at risk for development of spinocerebellar ataxia type 7, the method comprising conducting an assay on a nucleic acid sample from said human to determine the presence or absence of an expanded CAG trinucleotide repeat in a CAG repeat region of a spinocerebellar ataxia type 7 gene, wherein the presence of an expanded CAG trinucleotide repeat having the sequence (CAG) n , wherein n≧30, is indicative tat said human is at risk for development of spinocerebellar ataxia type 7, wherein said assay comprises:
a) amplifying a target portion of the nucleic acid using a pair of oligonucleotide primers which specifically amplify the region of nucleic acid containing CAG trinucleotide repeats to obtain an amplified product, wherein the oligonucleotide primers are SEQ ID NO:5 and SEQ ID NO:6;
b) determining the presence or absence of an expanded CAG trinucleotide repeat in said nucleotide sequence of said amplified product; and
c) determining that said human is at risk for development of SCA7 when n≧30.
3. The method of claim 2 wherein n≧37.
4. The method of claim 2 wherein n≧38.
5. A method for diagnosing spinocerebellar ataxia type 7 in a human patient, said method comprising detennining the presence or absence of an expanded CAG trinucleotide repeat in a CAG repeat region in a spinocerebellar ataxia type 7 gene in a nucleic acid sample from said patient, wherein the presence of an expanded CAG trinucleotide repeat having the sequence (CAG) n , wherein n≧30, is indicative of spinocerebellar ataxia type 7 in said patient, wherein the presence of an expanded CAG trinucleotide repeat is determined by amplification of nucleic acid containing the CAG trinucleotide repeat using a pair of oligonucleotide primers which specifically amplify the region of nucleic acid containing the expanded CAG trinucleotide repeat, detecting amplified products containing the CAG trinucleotide repeat reaion, wherein the oligonucleotide primers are SEQ ID NO:5 and SEQ ID NO:6, and determining that said human has SCA7 when n≧30.
6. The method of claim 5 wherein n≧37.
7. The method of claim 5 wherein n≧38.
8. A method for diagnosing spinocerebeliar ataxia type 7 in a human, said method comprising:
a) contacting nucleic acid from said human with oligonucleotide primers that amplify a region of nucleic acid containing CAG trinucleotide repeats in a CAG repeat region of a spinocerebellar ataxia type 7 gene, wherein the oligonucleotide primers are SEQ ID NO:5 and SEQ ID NO:6;
b) detecting an amplification product comprising an expanded CAG trinucleotide repeat region, whereby said detection of an expanded CAG trinucleotide repeat having to sequence (CAG) n , wherein n≧30, is indicative of spinocerebellar ataxia type 7 in said human; and
c) determining that said human has SCA7 when n≧30.