Inherited CAG.CTG allele length is a major modifier of somatic mutation length variability in Huntington disease.

Huntington disease (HD) is associated with an unstable trinucleotide CAG.CTG repeat expansion. Although the repeat length is inversely correlated with the age-at-onset of symptoms, variability between patients who have inherited the same HD repeat length clearly suggests that other factors influence this aspect of the disease.

Increased SK3 expression in DM1 lens cells leads to impaired growth through a greater calcium-induced fragility.

Although cataract is a characteristic feature of myotonic dystrophy type 1 (DM1), little is known of the underlying mechanisms. We generated four lens epithelial cell lines derived from DM1 cataracts and two from age-matched, non-DM cataracts. Small-pool PCR revealed typical large triplet repeat expansions in the DM1 cells.

Pms2 is a genetic enhancer of trinucleotide CAG.CTG repeat somatic mosaicism: implications for the mechanism of triplet repeat expansion.

The expansion of CAG.CTG repeat sequences is the cause of several inherited human disorders. Longer alleles are associated with an earlier age of onset and more severe symptoms, and are highly unstable in the germline and soma with a marked tendency towards repeat length gains.

Genomic context drives SCA7 CAG repeat instability, while expressed SCA7 cDNAs are intergenerationally and somatically stable in transgenic mice.

Spinocerebellar ataxia type 7 (SCA7) is an autosomal dominant cerebellar ataxia caused by a CAG repeat expansion in the ataxin-7 gene. In humans, SCA7 is characterized by marked anticipation due to intergenerational repeat instability with a bias toward expansion, and is thus regarded as the most unstable of the polyglutamine diseases. To study the molecular basis of CAG/CTG repeat instability and its pathological significance, we generated lines of transgenic mice carrying either a SCA7 cDNA construct or a 13.

Instability of a premutation allele in homozygous patients with myotonic dystrophy type 1.

Myotonic dystrophy type 1 (DM1) is caused by the expansion of an unstable CTG repeat in the DMPK gene on chromosome 19q13.3. We present two siblings with DM1 who each inherited a premutation allele, (CTG)43, stably transmitted from the mother and a full-mutation allele, either (CTG)500 or (CTG)180, derived from a paternal protomutation allele, (CTG)52.