The Clinical Heterogeneity of Spinal Muscular Atrophy with Respiratory Distress Type 1 (SMARD1)-A Report of Three Cases, Including Twins.

Spinal muscular atrophy with respiratory distress type 1 (SMARD1; OMIM #604320, ORPHA:98920) is a rare autosomal recessive congenital motor neuron disease. It is caused by variants in the gene. Clinically, it presents with respiratory failure due to diaphragmatic paralysis, progressive muscle weakness starting in the distal parts of the limbs, dysphagia, and damage to sensory and autonomic nerves.