Hemodynamic and clinical onset in patients with hereditary pulmonary arterial hypertension and BMPR2 mutations.

BACKGROUND: Mutations in the bone morphogenetic protein receptor 2 (BMPR2) gene can lead to idiopathic pulmonary arterial hypertension (IPAH). This study prospectively screened for BMPR2 mutations in a large cohort of PAH-patients and compared clinical features between BMPR2 mutation carriers and non-carriers. METHODS: Patients have been assessed by right heart catheterization and genetic testing. In all patients a detailed family history and pedigree analysis have been obtained. We compared age at diagnosis and hemodynamic parameters between carriers and non-carriers of BMPR2 mutations. In non-carriers with familial aggregation of PAH further genes/gene regions as the BMPR2 promoter region, the ACVRL1, Endoglin, and SMAD8 genes have been analysed. RESULTS: Of the 231 index patients 22 revealed a confirmed familial aggregation of the disease (HPAH), 209 patients had sporadic IPAH. In 49 patients (86.3% of patients with familial aggregation and 14.3% of sporadic IPAH) mutations of the BMPR2 gene have been identified. Twelve BMPR2 mutations and 3 unclassified sequence variants have not yet been described before. Mutation carriers were significantly younger at diagnosis than non-carriers (38.53 ± 12.38 vs. 45.78 ± 11.32 years, p < 0.001) and had a more severe hemodynamic compromise. No gene defects have been detected in 3 patients with HPAH. CONCLUSION: This study identified in a large prospectively assessed cohort of PAH- patients new BMPR2 mutations, which have not been described before and confirmed previous findings that mutation carriers are younger at diagnosis with a more severe hemodynamic compromise. Thus, screening for BMPR2 mutations may be clinically useful.

Sequence variants in BMPR2 and genes involved in the serotonin and nitric oxide pathways in idiopathic pulmonary arterial hypertension and chronic thromboembolic pulmonary hypertension: relation to clinical parameters and comparison with left heart disease.

BACKGROUND: Idiopathic pulmonary arterial hypertension (IPAH) and chronic thromboembolic pulmonary hypertension (CTEPH) share important pathogenic and clinical features. BMPR2 mutations are important in the pathogenesis of IPAH, but little is known about the genetic background in CTEPH. OBJECTIVE: To search for mutations and polymorphisms in genes involved in the BMPR2, serotonin and nitric oxide pathways possibly associated with pulmonary and cardiac disorders in IPAH and CTEPH. METHODS: In a cohort of Swiss patients with IPAH (n = 16) and CTEPH (n = 16), and in 24 controls with left heart disease without PH, polymorphisms in the BMPR2, 5-HHT, 5-HTR-2A and eNOS genes were analyzed and correlated with various clinical, functional and hemodynamic parameters. RESULTS: We found a BMPR2 missense mutation in a patient with coronary artery disease (CAD) without PH but no BMPR2 mutations in our collective with late-onset sporadic PH. In patients with polymorphic variants of the BMPR2 gene, the number of blood platelets and oxygen saturation were increased. The c.600A-->C synonymous variant was associated with worse exercise capacity and decreased quality of life in PH. We found no significant differences for any measured parameter according to the eNOS, 5-HTR2A and the 5-HTT polymorphisms, although there was a higher allelic frequency of the 5-HTT long variant in IPAH than in CTEPH and controls. CONCLUSION: Our first report of a BMPR2 mutation in a patient with CAD without PH is interesting and warrants further investigation. Our study may reflect the clinical status and genetic background in a typical PH cohort as seen in a single tertiary care referral center.

Identification of a new intronic BMPR2-mutation and early diagnosis of heritable pulmonary arterial hypertension in a large family with mean clinical follow-up of 12 years.

BACKGROUND: Mutations in the bone morphogenetic protein receptor 2 (BMPR2) gene can lead to hereditary pulmonary arterial hypertension (HPAH) and are detected in more than 80% of cases with familial aggregation of the disease. Factors determining disease penetrance are largely unknown. METHODS: A mean clinical follow-up of 12 years was accomplished in 46 family members including echocardiography, stress-Dopplerechocardiography and genetic analysis of TGF-ß pathway genes. Right heart catheterization and RNA-analysis was performed in members with pathological findings. RESULTS: Manifest HPAH was diagnosed in 8 members, 4 were already deceased, two died during the follow-up, two are still alive. Normal pulmonary artery systolic pressure at rest but hypertensive response to exercise has been identified in 19 family members. Analysis of BMPR2 transcripts revealed aberrant splicing due to an insertion of an intronic Alu element adjacent to exon 6. All HPAH patients and 12 further asymptomatic family members carried this insertion. During follow-up two family members carrying hypertensive response and the Alu insertion developed manifest HPAH. CONCLUSION: This is the first report of an intronic BMPR2 mutation due to an Alu element insertion causing HPAH in a large family which has been confirmed on RNA-level. Only those members that carried both hypertensive response and the mutation developed manifest HPAH during follow-up. Our findings highlight the importance of including further methods such as RNA analysis into the molecular genetic diagnostic of PAH patients. They suggest that at least in some families hypertensive response may be an additional risk factor for disease manifestation and penetrance.