Freidreich's ataxia with retained reflexes: a phenotype and genotype correlation.

An 18-year-old lady had presented to us with insidious onset progressive gait ataxia of 5-year duration. Her sister had similar complaints and type 1 diabetes mellitus. Examination revealed, gait ataxia, impaired tandem gait, babinski sign and severe swaying on testing for Romberg's sign. All deep tendon reflexes were exaggerated. On investigations, there was no evidence for diabetes mellitus or nutritional deficiencies. Electrocardiogram and echocardiogram were normal. Magnetic spine resonance showed marked atrophy of cervical cord with normal cerebellum. The genetic testing disclosed expanded GAA repeat length on both alleles of FXN gene. The GAA repeat length on both alleles was much less than mean length observed in Friedreich's ataxia. This case highlights how strongly the genotype influences the neurological and systemic manifestations as well as severity of disease in Friedreich's ataxia.