A gene for hypospadias in a child with presumed tetrasomy 18p.

The proband and his elder brother had intrauterine growth retardation, hypospadias, cryptorchism, a high palate, distally placed axial triradii, and a functional and maturational CNS defect that improved with age and included the inability to suck, severe swallowing difficulties, and frequent vomiting. Their hypospadias is due to an autosomal dominant gene. The proband also had a small extra metacentric chromosome presumed to be an isochromosome 18p.