Familial pulmonary arterial hypertension, leucopenia, and atrial septal defect: a probable new familial syndrome with multisystem involvement.

ABSTRACT

We present two siblings with identical clinical findings that seem to represent a previously unreported familial syndrome. Major findings involve three systems pulmonary arterial hypertension, cardiac abnormalities including secundum-type atrial septal defect, and the hematopoietic system with intermittent neutropenia, lymphopenia, monocytosis, and anemia. The siblings also shared several minor abnormalities pectus carinatum, long fingers, proximally placed thumb, broad nasal bridge, and high-arched palate. The male proband also had bilateral inguinal hernias and undescended testes. The same findings in two siblings suggest a genetic cause--either an autosomal recessive disorder or germline mosaicism in one parent for a dominant mutation. Investigations revealed a bone morphogenetic protein receptor 2 polymorphism in intron 4 in only one sibling, which was also present in unaffected maternal relatives.