X-linked myotubular myopathy with a novel MTM1 mutation in a Taiwanese child.

We report a male, preterm newborn infant with X-linked myotubular myopathy, the most severe type of the disease. He presented at birth with generalized hypotonia, difficulty in swallowing, and respiratory distress with frequent episodes of atelectasis. The infant had a long thin face, generalized hypotonia, and arachnodactyly. Diagnosis was based on fetal history, muscle histopathology, electron microscopy and a genetic study. A base pair change was detected in exon 11 of the MTM1 gene: c.1160C>A, which caused an amino acid change, p.S387Y. The father's gene was normal but the mother had the same mutation as her son and was thus a carrier.