The Number of CAG Repeats Within the Normal Allele Does Not Influence the Age of Onset in Huntington's Disease

Abstract

The purpose of this work was to examine the interaction between the normal and mutant alleles of this gene and their effect on the clinical onset of HD. Although the Cox regression coefficient of 0.15 was significant (P < 0.0001), the regression model explained only 28% of the variance of the age at onset related to the effect of the number of CAG repeats within normal allele.

Within the groups of patients with the same number of CAG repeats of the mutant allele, number of CAG repeats of the normal allele was found uncorrelated to the age at onset. Furthermore, when analyzing subgroups of patients with the same allelic composition on both alleles, we failed to observe any correlation with the age at the onset.

Keywords

• Huntington's disease
• CAG triplet
• age at onset
• trinucleotide repeat
• length
• gene
• mutation
• hd
• instability
• chromosomes
• dysfunction
• progression
• mosaicism