Familial holoprosencephaly, heart defects, and polydactyly.

We describe a pair of sibs with microcephaly, hypoplastic nose, cleft lip/palate, a complicated Fallot-like cardiac defect, and holoprosencephaly and polydactyly. One sib appeared to have normal chromosomes. The healthy parents were second cousins. This constellation of signs has been described before in at least 14 other patients, and was possibly present in several others. Although there is overlap with a number of similar conditions, especially hydrolethalus syndrome, this probably represents a separate entity. Three pairs of sibs and consanguinity in 3 families point to autosomal recessive pattern of inheritance.