Clinico‑genetic heterogeneity of chondrodysthrophic myotonia

Abstract

Chondrodystrophic myotonia characterized by generalized myotonic myopathy, masklike face, skeletal dysplasia, contracture of joints,
growth retardation and bone maturation delay. Two types have been defined by the age of manifestation of the symptoms: the severe neonatal form, sometimes called type 2 (Stuve–Wiedemann syndrome), and the classical form (Schwartz–Jampel syndrome) with late infantile or childhood manifestation. Therapy targets electrical stabilization of the muscle membrane. Successful therapies include anticonvulsants and antiarrhythmic drugs.