Ivemark's "asplenia" syndrome: a single gene disorder.

Congenital heart defects as a group represent a significant proportion of congenital malformations. Most are isolated and multifactorially determined; a relatively small proportion are due to a single gene defect, and result in an increased risk of recurrence among first-degree relatives. We have reported the cases of three male siblings with Ivemark's "asplenia" syndrome to support an autosomal recessive mode of inheritance. We have stressed the importance of early recognition of mendelian disorders with associated cardiac malformations to provide meaningful counseling regarding prognosis, medical management, and risk of recurrence.