Spinal Muscular Atrophy in African Children

Abstract

Forty-five African children with SMA were seen over a period of five years. Fifteen had severe infantile form (Group 1), 19 intermediate (Group 2), 9 juvenile (Group 3) and 2 cervical type. A positive family history was obtained in only 9% of patients. The female/male ratio was 1:1.7. The age of onset was under four months in Group 1, between 5-24 months in Group 2. In 77% of Group 3 onset was between 5-24 months, 22% between 25-48 months. The lower limbs were more severely affected than upper limbs in all except the two patients with cervical SMA, proximal muscles more than distal in 82% and proximal and distal muscle were equally affected in 18%. Bulbar weakness was present in 73% and facial weakness in 80% of Group 1 patients only. Fasciculation of tongue occurred in 50% of Group 1, 42% of Group 2 and 44% of Group 3 patients. Tremor of hands was seen in none of the patients in Group 1, 58% in Group 2 and 66% in Group 3. Tendon reflexes were absent or depressed in all except one patient in Group 2 and were normal in the legs of the two patients with cervical SMA. The blood CK was elevated in 26% of patients. An ECG "tremor" was present in 26% of patients in Group 1, 68% in Group 2 and 66% in Group 3. Four patients (all in Group 1) died of pneumonia; the outcome in the others is not known. The clinical findings in these 45 African children with SMA are similar to those reported from Europe, Asia and America except in two aspects (I) paucity of positive family history (only 9%) and (II) frequent (80%) involvement of facial muscles in the severe infantile form of SMA.

Key words

Spinal muscular atrophy - Childhood - African