Article Document Academic Article Information Content Entity Journal Article Continuant Continuant Entity Entity Generically Dependent Continuant 2025-05-10T17:13:46 RDF description of Interaction of normal and expanded CAG repeat sizes influences age at onset of Huntington disease - http://repository.healthpartners.com/individual/document-rn18501 119a Aged 24652 Adolescent 2022-02-21T22:48:57.408-06:00 Huntington Disease/*genetics Cohort Studies Child 3 Interaction of normal and expanded CAG repeat sizes influences age at onset of Huntington disease public *Trinucleotide Repeats 15036 Age of Onset New England <p>Huntington disease (HD) is a neurodegenerative disorder caused by the abnormal expansion of CAG repeats in the HD gene on chromosome 4p16.3. Past studies have shown that the size of expanded CAG repeat is inversely associated with age at onset (AO) of HD. It is not known whether the normal Huntington allele size influences the relation between the expanded repeat and AO of HD. Data collected from two independent cohorts were used to test the hypothesis that the unexpanded CAG repeat interacts with the expanded CAG repeat to influence AO of HD. In the New England Huntington Disease Center Without Walls (NEHD) cohort of 221 HD affected persons and in the HD-MAPS cohort of 533 HD affected persons, we found evidence supporting an interaction between the expanded and unexpanded CAG repeat sizes which influences AO of HD (P = 0.08 and 0.07, respectively). The association was statistically significant when both cohorts were combined (P = 0.012). The estimated heritability of the AO residual was 0.56 after adjustment for normal and expanded repeats and their interaction. An analysis of tertiles of repeats sizes revealed that the effect of the normal allele is seen among persons with large HD repeat sizes (47-83). These findings suggest that an increase in the size of the normal repeat may mitigate the expression of the disease among HD affected persons with large expanded CAG repeats.<p> 10.1002/ajmg.a.20190 Survival Rate Probability document-rn18501 American Journal of Medical Genetics. Part A