Neonatal myotubular myopathy with respiratory distress: report of a case

The case of a 2-day-old male full-term newborn with myotubular (centronuclear) myopathy is reported. He presented with generalized hypotonia and muscle weakness, swallowing disturbance, and respiratory distress at birth. He had a typical myopathic face, high-arched palate, funnel chest, and mild bilateral ptosis. Deep tendon reflexes were absent. Serum creatine kinase was normal. The histologic examination of the muscle biopsy over the right rectus femoris muscle revealed an increased number of fibers with centrally placed nuclei, type 1 fiber predominance, type 1 fiber atrophy, and a peripheral halo in the sarcoplasm on NADH-TR staining. On electron microscopy, central nuclei were separated by strands of glycogen and mitochondria. His muscle strength showed clinical improvement at a 14-month follow-up. This case illustrates the need for a muscle biopsy and histochemical staining and/or electron microscopic investigation for a proper diagnosis in hypotonic newborns with respiratory distress.