Clinical and genetic correlate in childhood onset Friedreich ataxia

We analyzed the clinical and genetic aspects of 28 FRDA patients from 20 fa milies. 19 families were consanguineous. The onset was between 4 and 131/2 years of age (mean 15.4 +/- 6.2). Three patients presented with cardiomyopa thy, one with weakness, and the rest with ataxia. There were two patients w ith preserved lower-limb deep tendon reflexes. Sensory nerve action potenti als were reduced in 14/14 patients. Cardiac echograms were abnormal in 17/1 9 cases, and this was between 6 and 16 years of age (mean 10.1 +/- 3.5). Fo ur families were multiplex. Clinical intra-familial variability was observe d. Increased GAA repeats of the X25 gene were found in 27/28 patients studi ed, all in a homozygous state. 88.9 % of patients had a smaller allele larg er than 500 repeats, and 66.7 % had more than 700 repeats. The patient who did not have increased CAA repeats in both alleles had peculiar findings. S ignificant correlation of expansion was obtained for the early onset, and c ardiomyopathy as the onset.