We evaluated the association between age at onset of Friedreich's ataxia and alleles of two restriction fragment length polymorphisms (RFLP) at D9S15 and D9S5 in the 9gl3-9g21.1 region. We studied 65 Italian patients from 49 families. Age at onset was not normally distributed in our patients, suggesting allelic heterogeneity. Patients homozygous for allele 1 of MspI RFLP detected by probe MCT112 at D9S15 (M1) had an earlier onset (mean 9.3, SD 3.4 years) than patients homozygous for allele 2 (M2; mean 12.1, SD 4.3). Heterozygotes had an onset age similar to that of the M2 homozygotes. These findings suggest that the M1 allele might be a marker of one allelic early-onset Friedreich's ataxia mutation.
- Age at onset
- Friedreich's ataxia
- Restriction fragment length polymorphisms
ASJC Scopus subject areas
- Clinical Neurology