[Neonatal muscular spinal atrophy: a case report].

Spinal Muscular Atrophy (SMA) is an autosomal recessive disease characterized by diffuse proximal and distal weakness due to deletions of the survival motor neuron (SMN) gene localised on chromosome 5q13. Pathological studies show decreased numbers of motorneurons in spinal cord. SMA was initially sub-classified clinically into three types base on age at onset and clinical course. SMA type 1, Werdnig-Hoffmann disease, has an onset within the first 6 months and death within the first two years. In contrast, SMA type II has an onset after six months of life and the children achieve the ability to sit unaided. Children with SMA type III (Kugelberg-Welander) usually have normal milestones in the first year and achieve the ability to walk but then show evidence of mild weakness. The prognosis is good and the clinical course is not (or very slowly) progressive. Recently, Dubowitz described a new form of SMA called type 0 with a neonatal onset, facial weakness, progressive and fatal clinical course. These infants show generalised hypotonia, the lower limbs are more affected than the upper with marked weakness of all axial muscles. We report a case of SMA, uncommon for the early onset and the respiratory difficulties. The diagnosis has been done by genetic analyses showing a SMN mutation.