Obstetrics & Gynecology; Human Genetics; Ophthalmology; Howard Hughes Medical Institute; Neurology
Gouw, Launce G.; McKenna, Catherine K.; Digre, Kathleen B.; Placek, Louis J.
Castaneda, Marco A.; Pulst, Stefan M.; Perlman. Susan M.; Lee, M.S.; Gomez, Christopher; Fischbeck, Kenneth; Gagnon, Deborah; Storey, Elsdon; Bird, Thomas; Jeri, F. Raul
Analysis of the dynamic mutation in the SCA7 gene shows marked parental effects on CAG repeat transmission.
The gene for spinocerebellar ataxia 7 (SCA7) includes a transcribed, translated CAG tract that is expanded in SCA7 patients. We have determined expansions in 73 individuals from 17 SCA7 kindreds and compared them with repeat lengths of 180 unaffected individuals. Subjects with abnormal expansions comprise 59 clinically affected individuals and 14 at-risk currently unaffected individuals predicted to carry the mutation by haplotype analysis. For expanded alleles, CAG repeat length correlates with disease progression and severity and correlates inversely with age of onset. Increased repeat lengths are seen in generational transmission of the disease allele, consistent with the pattern of clinical anticipation seen in these kindreds. Repeat lengths in expanded alleles show somatic mosaicism in leukocyte DNA, suggesting that these alleles are unstable within individuals as well as between generations. Although dynamic repeat expansions from paternal transmissions are greater than those from maternal transmissions, maternal transmission of disease is more common, suggesting germline or embryonic effects of the repeat expansion.
IRL Press at Oxford University Press
Genetics; Biosynthesis; SCA7 Gene
Age of Onset; Alleles; Analysis of Variance; DNA Primers; Disease Progression; Genomic Imprinting; Nerve Tissue Proteins; Polymerase Chain Reaction; Protein Biosynthesis; Regression Analysis; Spinocerebellar Degenerations;
Gouw LG, Castaneda MA, McKenna CK, Digre KB, Pulst SM, Perlman S, Lee MS, Gomez C, Fischbeck K, Gagnon D, Storey E, Bird T, Jeri FR, Ptacek LJ. Analysis of the dynamic mutation in the SCA7 gene shows marked parental effects on CAG repeat transmission. Hum Mol Genet. 1998 Mar;7(3):525-32. Retrieved October 9, 2006 from http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?CMD=Display&DB=pubmed