Genetic and Environmental Characteristics of Primary Pulmonary Hypertension

BACKGROUND: PPH is a progressive disease that causes obstruction of the smallest arteries in the lungs, which often leads to heart failure. It threatens the lives of thousands of individuals. PPH affects both genders at any age, although females are affected twice as often as males. In a recent important advance, mutations in BMPR2 were associated with both familial and sporadic PPH. Because only 20% of people with a BMPR2 mutation ever develop PPH, other genes or modifying biologic events must contribute to the clinical development of the disease. PPH was recently renamed Idiopathic Pulmonary Arterial Hypertension or Familial Pulmonary Arterial Hypertension. DESIGN NARRATIVE: This study will utilize a database and specimen bank developed from 100 families affected by PPH across the United States. In families with genetic mutations not yet identified, changes in the BMPR2 gene will be studied, including in the promoter and intronic regions, and chance recombination events that could confirm another locus near 2q33 will be examined. New methods will look for modifier genes in large families with known mutations; examine kindreds for mitochondrial DNA haplotypes; and test candidate genes, including NOS-1, NOS-3, and the serotonin transporter. This study will determine the functional mechanisms by which variations found in the BMPR2 alleles alter BMP signal transduction by defining the biochemical effects of the mutant proteins on signaling pathways. In addition, the study will examine the perceived risks and benefits of clinical genetic testing and counseling in individuals from families at high risk for PPH and will determine how this new information might be most helpful to these individuals and their families.