Simpson-Golabi-Behmel syndrome with severe cardiac arrhythmias.

We report on a family with 2 affected males with the X-linked Simpson-Golabi-Behmel (SGB) syndrome. The propositus was a 33-year-old man with pre- and postnatal overgrowth, "coarse" face with hypertelorism, broad nose, wide mouth, malposition of teeth, submucous cleft, accessory nipples, broad hands with hypoplastic index finger nails, and operated left postaxial hexadactyly. From the age of 26 years he suffered from severe tachyarrhythmias, requiring recurrent defibrillations. The brother of the propositus was macrosomic at birth and had a similar facial appearance. In addition he had a pyloric stenosis and a 3/6 systolic murmur. He died at age 4 months. Cardiac defects and conduction disturbances are major components of the SBG syndrome and can be responsible for death in early infancy and perhaps for cardiac arrest in the adult.