675 Spinal Muscular Atrophy: Two Cases of Rapidly Progressive Disease

Introduction: Spinal muscular atrophies (SMAs) are a group of autosomal recessive disorders characterized by progressive lower motor neuron degeneration Several types have been identified, including the acute infantile form - SMA type I or Werdnig-Hoffman's disease, of which we report two cases. Case 1: 46-day old male caucasian infant, nonconsanguineous parents, no relevant family history; admitted for progressive global hypotonia and poor feeding starting at 2 weeks of life. On physical examination, the following was noted: supine “frog position”; axial hypotonia; rare spontaneous distal motor activity; bell-shaped chest; abdominal breathing with transient polypnea; flexed toes; clawed left hand; tongue fasciculation. Cardiac assessment was normal. Laboratory tests showed respiratory acidosis. Transfontanellar ultrasound revealed no abnormalities Electromyography was consistent with SMA; genetic study confirmed the diagnosis. Three months later, the infant was readmitted for severe respiratory infection and died due to respiratory failure. Case 2: 2-month old caucasian male term infant, non-consanguineous parents; referred to the Pediatric Department at 1 month old for progressive generalized hypotonia (starting at 2nd week), monotone motor activity and abnormal breathing pattern. Physical examination disclosed: supine “frog position”; clawed hands; head lag; global hypotonia in prone position; absent osteotendinous, Moro, palmar and plantar reflexes; bell-shaped chest; paradoxal breathing Electromyogram was consistent with SMA, confirmed by genetic study. Commentary: Werdnig-Hoffman's disease has a poor prognosis, death usually occuring in the first years of life No curative treatment is currently available Early diagnosis is key for both management of supportive care and genetic counseling.