OCCURRENCE OF PRIMARY PULMONARY HYPERTENSION IN TWINS WITH A REVIEW OF ETIOLOGICAL CONSIDERATIONS

1. 1. Two autopsy-proved cases of primary pulmonary hypertension in twins have been reported. 2. 2. The myriad of etiologic considerations of this disease have been reviewed. 3. 3. The repeated observations of this disease in families suggest the possibility of genetic implications in some cases. 4. 4. The etiology of primary pulmonary hypertension continues to challenge the physician. It may well be that there is no one single answer. The increased pulmonary vascular resistance which ultimately produces the entire clinical spectrum of this disease may indeed represent the response of the pulmonary vascular bed to a multiplicity of causes. Review of reported cases strongly suggests this possibility. © 1968.