G.P.192

After uneventful pregnancies, two newborn siblings, a girl and a boy – another sibling was stillborn – developed inspiratory stridor, hypertrophy of the right cardiac ventricle, reduction in spontaneous movements and mildly elevated creatine kinase. Muscle biopsies at ages of three months and seven weeks were performed and respectively, revealed a 'prepathological' pattern of infantile neurogenic atrophy suggesting spinal muscular atrophy (SMA). However, molecular analyses of SMN (SMA) and IGHMBP2 (SMARD1) genes did not disclose any mutations. Further histochemical staining of the skeletal muscle and heart demonstrated almost complete absence of cytochrome c oxidase while SDH was preserved.…