Severe lethal spinal muscular atrophy variant with arthrogryposis.

Spinal muscular atrophies are a clinically and genetically heterogeneous group of disorders. Atypical forms of the disease have also been described, including those with associated sensory deficits, hearing loss, cerebellar hypoplasia, congenital heart defects, arthrogryposis, and bone fractures at birth. The patient described here is a male infant, born to a 30-year-old mother at 34 weeks of gestation complicated with polyhydramnios. The first son of consanguineous parents had died with the same clinical features. The patient required ventilatory support because of respiratory failure after the birth and died on day 13. His physical examination revealed profound generalized hypotonia, absence of deep tendon and neonatal reflexes, dysmorphic facies, arthrogryposis, clinodactyly, and left femur fracture. A muscle biopsy revealed variation in fiber size with occasional hypertrophic fibers. The postmortem examination revealed loss and degeneration of anterior horn cells. We propose that the patient, who presented with severe hypotonia, femur fracture, arthrogryposis, dysmorphic features, history of early death of his brother with the same clinical features and parental consanguinity, had probable X-linked spinal muscular atrophy. However, autosomal-recessive inheritance can not be completely excluded.