ORIGINAL ARTICLESFamilial pulmonary arterial hypertension, leucopenia, and atrial septal defect: a probable new familial syndrome with multisystem involvementDursun, Alia; Ozgul, R. Koksala e; Soydas, Aslia; Tugrul, Tugbab; Gurgey, Aytemizc; Celiker, Alpayd; Barst, Robyn J.f; Knowles, James A.g; Mahesh, Mansukhanih; Morse, Jane H.iAuthor Information Faculty of Medicine, Departments of Pediatrics, aMetabolism and Nutrition Unit bImmunology Unit cHematology Unit dCardiology Unit eInstitute of Child Health, Hacettepe University, Ankara, Turkey Departments of Pediatrics, fPediatric Cardiology gClinical Psychiatry hClinical Pathology iDepartment of Medicine, Columbia University College of Physicians and Surgeons, New York, USA Correspondence to Ali Dursun, MD, PhD, Department of Pediatrics, Metabolism and Nutrition Unit, Hacettepe University, Sihhiye 06100, Ankara, Turkey Tel: +90 312 3051141; fax: +90 312 3100863; e-mail: email@example.com Received 31 March 2008 Accepted 4 September 2008 Clinical Dysmorphology: January 2009 - Volume 18 - Issue 1 - p 19-23 doi: 10.1097/MCD.0b013e32831841f7 Buy Metrics 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. © 2009 Lippincott Williams & Wilkins, Inc.