April 18, 2018 e-Pearl of the Week: Schwartz-Jampel syndrome

Schwartz-Jampel syndrome

Schwartz-Jampel syndrome (SJS) is a rare autosomal recessive disorder associated with developmental skeletal muscle abnormalities, facial dysmorphism, and prominent and diffuse myotonia that is usually present at birth. Muscles often appear hypertrophied and movement is slow due to stiffness related to the myotonia. There is considerable clinical heterogeneity in this syndrome. Type 1A is recognized in childhood and exhibits only moderate bone dysplasia, and type 1B is similar but manifests at birth with more prominent bone dysplasia. Both result from mutations in the HSPG2 gene¹. Type 2 (also known as Stuve-Wiedemann syndrome) is the most severe and uncommon phenotype with a genetically distinct mutation in the LIFR gene, with extremely high mortality in the neonatal period². Needle EMG can help in the diagnosis by showing myotonic discharges³. Treatment is restricted to supportive care and symptomatic management.

References

1. Stum M, Davoine CS, Vicart S, et al. Spectrum of HSPG2 (Perlecan) mutations in patients with Schwartz-Jampel syndrome. Hum Mutat 2006; 27: 1082–1091.
2. Basiri K, Fatehi F, Katirji B. The Schwartz-Jampel Syndrome: Case report and literature review. Adv Biomed Res 2015; 4: 163.
3. Spanns F, Theunissen P, Reekers A, Smit L, Veldman H. Schwartz-Jampel syndrome: I. Clinical, electromyographic and histologic studies. Muscle Nerve 1990; 13: 516–527.
 

Submitted by Ronnyson Susano Grativvol, MD – Department of Neurology, University of São Paulo, Brazil.

Dr. Grativvol reports no disclosures.