A case of monozygotic male twins discordant for skeletal and cardiac defect is reported. One twin had the hemifacial microsomia type of the oculo-auriculo-vertebral dysplasia. The cotwin had no asymmetry of the face and normal ears, but preaxial polydactyly and ventricular and auricular septal defects. The cotwins were concordant for craniostenosis with a ridge metopic suture. Karyotypes were normal.