The case of a neonate with a rapidly fatal course of nemaline myopathy is reported. Neonatal history and clinical findings suggested a postasphyxia syndrome, but dependence on mechanical ventilation in the absence of severe brain damage or evidence of heart and lung involvement prompted us to perform a muscle biopsy. The typical rod-shaped bodies of nemaline myopathy were observed in skeletal and heart muscle which is unusual in infantile forms. Neonatal bone fractures, which have not been reported previously, were detected. Due to the rapid evolution of the neonatal form, many of these patients may die undiagnosed in the perinatal period, the families remaining unaware of the existence of the genetic disorder. Therefore, if severe hypotonia persists in a neonate, together with dependence on assisted breathing, specific examinations, such as muscle enzyme determination, NCV, EMG and if indicated, muscle biopsy should be performed to rule out neuromuscular disease.
