PRESENCE OF EMERINOPATHY IN CASES OF RIGID SPINE SYNDROME

Rigid spine syndrome (RSS) shows clinical similarities to Emery-Dreifu ss muscular dystrophy (EDMD). Differential diagnosis between EDMD and RSS is essential because EDMD is often associated with life-threatenin g cardiomyopathy that can be cured by an implantation of a cardiac pac emaker. To determine if any of the patients with RSS had mutations of the emerin gene (responsible gene for X-linked EDMD or emerinopathy), we screened the patients for mutations. We found seven patients with a clinical picture consistent with RSS in the 6500 diagnostic muscle bi opsies in our National Center over the last 19 years. We identified a novel mutation in the gene (1-bp frame-shift deletion in the exon 1) i n one of the seven patients with RSS. This mutation created a prematur e termination at codon 12 and was expected to produce a severely trunc ated emerin. Emerin was not detected in the skeletal muscle. The unaff ected mother of the patient was a heterozygous carrier for the mutatio n. The remaining six patients with RSS had no mutation in the gene and showed normal expression of emerin in the skeletal muscle. Our result s emphasize the presence of clinical overlap between possible RSS and EDMD, and reinforce the necessity of molecular genetic diagnosis of em erin to exclude emerinopathy in a patient population that has a clinic al diagnosis of RSS. (C) 1998 Elsevier Science B.V. All rights reserve d.