Objective: Pulmonary arterial hypertension (PAH) is a rare disease that can have a familial component. It has been shown that more than 50% of cases of familial PAH are associated with mutations in the gene encoding bone morphogenetic protein receptor 2 (BMPR2), which acts as a receptor for members of the transforming growth factor beta superfamily. Some studies in patients with idiopathic PAH have also shown varying percentages of mutations in this gene. The aim of this study was to determine the frequency of these mutations in a group of patients with idiopathic PAH.
Patients and methods: The study population included patients with idiopathic PAH who were seen during 2006 in our unit specialized in this entity. Patients were excluded if they had relatives who had been diagnosed with PAH or who had symptoms that led to suspicion of the disease. Diagnosis was obtained according to the protocol used in our unit. A hemodynamic study was carried out in all cases and patients were included if they had a mean pulmonary arterial pressure of greater than 25 mm Hg. DNA was extracted from peripheral leukocytes and amplified by polymerase chain reaction. Seventeen primer pairs were used for the 13 exons that make up the gene. Using the single strand conformational polymorphism (SSCP) technique we detected anomalous DNA fragments for subsequent sequencing.
Results: The study included 8 patients (4 women). In 5 patients, no abnormalities were observed, whereas in the remaining 3, anomalous electrophoresis patterns were obtained in the SSCP and sequencing revealed mutations. In 1 case, 2 different electrophoresis patterns were observed by SSCP, but it was only possible to sequence 1 of them due to the low concentration of DNA obtained.
Conclusions: The presence of mutations in the gene encoding BMPR2 is not infrequent in patients with idiopathic PAH, suggesting that this family of growth factors may be important in the pathogenesis of the disease and could have therapeutic implications.