Madras motor neuron disease variant, clinical features of seven patients.

Madras motor neuron disease (MMND) has the characteristic features of onset in the young, atrophy and weakness of the limbs, multiple cranial nerve palsies particularly the seventh, ninth to twelfth and sensorineural hearing loss with unique geographic distribution to southern part of India. During a period of 28 years (1974-2001), 7 (13%) among 54 patients of MMND seen at a tertiary referral center at Bangalore, India, had the additional features of optic atrophy in all and cerebellar involvement in three of them. There were three males and four females, the mean age at onset was 11.7 years, with a mean duration of illness of 6.4 years. All except one patient were ambulant and independent in the activities of daily living. Family history of MMND was present in more than a quarter (28.6%) of patients. Compared to MMND, these patients had onset of illness at a younger age and family history was more frequently observed, however, these differences were not statistically significant. Bulbar palsy was an invariable feature, being present in all patients compared to 38.3% of MMND and the difference was statistically significant (p=0.003). This clinical profile may be considered to be a variant of Madras motor neuron disease (MMNDV).