COANCESTRY IN APPARENTLY SPORADIC PRIMARY PULMONARY-HYPERTENSION

Objective: To examine sporadic cases of primary pulmonary hypertension for coancestry. Design: An epidemiologic study of families of patient s with primary pulmonary hypertension. Setting: A university-affiliate d referral population. Participants: Family members of 13 patients wit h primary pulmonary hypertension. Measurements: Family pedigrees invol ving grandparents, parents, siblings, and children were supplemented b y genealogic records. Coefficients of kinship (CK) were calculated for the patients with primary pulmonary hypertension who demonstrated coa ncestry and compared with 500 sets of controls drawn at random from ge nealogic records. Results: Two patients with sporadic primary pulmonar y hypertension demonstrated coancestry, The great-great grandfather an d great-great grandmother of one patient were the great-grandfather an d great-grandmother of the other patient. No other cases of primary pu lmonary hypertension were identified in these two families. The Ck of the affected individuals (Ck=10.02x10(-5)) suggests strongly that the observed relationship did not occur by chance alone. Among 500 random sets of matched controls, only two sets yielded Ck of 10.02x10(-5) or greater (p=0.004). Coancestry could not be identified for the other fi ve families of patients with sporadic primary pulmonary hypertension f or whom genealogic records were available. Conclusions: The finding of coancestry in patients with sporadic primary pulmonary hypertension s uggests that a genetic basis exists for some patients with apparently sporadic primary pulmonary hypertension. Familial primary pulmonary hy pertension may be more common than previously recognized.