Mutation of gene in spinal muscular atrophy respiratory distress type I.

Spinal muscular atrophy with respiratory distress type I (SMARD1, MIM #604 320) is an uncommon variant of infantile spinal muscular atrophy type I. Distinguishing features include diaphragmatic palsy, early-onset distal limb wasting, and contracture. This report describes a Chinese male with typical features of spinal muscular atrophy with respiratory distress type I. Direct sequencing of the causative gene, the immunoglobulin mu-binding protein 2 (IGHMBP2) gene, revealed the presence of a novel frameshift mutation caused by deletion of G in exon 13 and a single base pair substitution of G to A in exon 12 resulting in substitution of isoleucine for valine.