Neonatal diagnosis of Schwartz-Jampel syndrome with dramatic response to carbamazepine.

We report a female infant, born at 30 weeks of gestation, who exhibited generalized myotonia, facial dysmorphism, blepharophimosis, and short stature at birth. These clinical findings, along with abnormal electromyogram and muscle biopsy, are consistent with Schwartz-Jampel syndrome. Our patient, diagnosed at 4 weeks of life, lacks the major skeletal anomalies, such as pectus carinatum, congenital hip dysplasia, and bowing of the long bones usually associated with this syndrome. Treatment with carbamazepine, initiated at age 7 months (corrected age of 5 months) has produced marked and continued resolution of myotonia, lessened malformation of her bell-shaped chest, and developmental progress. We suggest that the relaxation of myotonia due to early diagnosis and treatment may prevent development of the classic skeletal dysplasia of Schwartz-Jampel syndrome.