Diagnostic criteria for FRDA proposed by Geoffroy et al71 and Harding.6 The diagnostic criteria of Harding are more liberal, allowing the diagnosis of FRDA in the early stages of the disease
| Criteria | Geoffroy et al, 1976 | Harding, 1981 |
| Primary (essential for diagnosis) | (1) Onset before the end of puberty (never after the age of 20 years), (2) progressive ataxia of gait, (3) dysarthria, (4) loss of joint position or vibration sense, (5) absent tendon reflexes in the legs, (6) muscle weakness | (1) Age of onset of symptoms before the age of 25 years, (2) progressive unremitting ataxia of limbs and of gait, (3) absence of knee and ankle jerks |
| Secondary | (1) Extensor plantar responses, (2) pes cavus, (3) scoliosis, (4) cardiomyopathy | (1) Dysarthria, (2) extensor plantar responses |
| Additional | If secondary criteria are absent, the following have to be present: (1) an affected sib fulfilling primary and secondary criteria, (2) median motor nerve conduction velocities of greater than 40 m/s thus excluding cases of type I hereditary motor and sensory neuropathy (HMSN) |