Genomic Comparison With Supercentenarians Identifies RNF213 as a Risk Gene for Pulmonary Arterial Hypertension

Circ Genom Precis Med. 2018;11:e002317. DOI: 10.1161/CIRCGEN.118.002317 December 2018 Hisato Suzuki, MD Masaharu Kataoka, MD Takahiro Hiraide, MD Yuki Aimi, MHS Yoshitake Yamada, MD Yoshinori Katsumata, MD Tomohiro Chiba, MD Kohsuke Kanekura, MD Sarasa Isobe, MD Yasunori Sato, PhD Toru Satoh, MD Shinobu Gamou, PhD Keiichi Fukuda, MD Kenjiro Kosaki, MD Pulmonary arterial hypertension (PAH) is characterized by a strong genetic component. About 30% of patients with idiopathic or heritable PAH are considered to have monogenic disorders: most of these patients have heterozygous BMPR2 mutations.1 The causative genes, if any, in the remaining 70% of patients have yet to be clarified. In some rare diseases, relatively common pathogenic variants, together with monogenic mutations, can play significant roles. We hypothesized that such potentially disease-causing variants, if associated with PAH, would be absent among an extremely long-lived healthy cohort because the lifespans of patients with PAH are limited. Accordingly, we looked for candidate variants that were enriched among patients with PAH but absent among supercentenarians who had lived for >110 years. The data, analytical methods, and study materials will not be made available to other researchers for the purposes of reproducing the results or replicating the procedure. We performed a standard whole-exome analysis in 2 cohorts: (1) 76 Japanese patients with idiopathic PAH who had tested negative for BMPR2 and other known pathogenic gene mutations, and (2) 79 Japanese supercentenarians, none of whom had past histories of any significant health problems. The study was approved by an institutional review committee, and the subjects gave informed consent. Patients with idiopathic PAH (19 males, 57 females) were diagnosed according to the Japanese Circulation Society guideline, and their age and mean pulmonary arterial pressure at diagnosis were 35.8±16.7 (mean±SD) years old and 49.6±15.5 mm Hg, respectively. Sequencing was performed using a HiSeq 2500 platform (Illumina, San Diego, CA) and SureSelectXT Human All Exon Kit (Agilent Technologies, Santa Clara, CA) for hybridization capture. The software Filtus, which implements a statistical modeling framework, allowed the detection of genes with distinctive variant distributions between the 2 cohorts using exome datasets under the assumption that mutations occur within a gene in a random manner with a probability proportional to the relative gene length.2 We identified 2 genes with rare variants (ie, minor allele frequency <0.01) that were deviately present in the PAH-group, compared with the supercentenarian group (with a threshold P of 8×10–8): variants in RNF213 and TMEM8A were present among the PAH cohort but were completely absent among the cohort of supercentenarians. RNF213 has an established role in angiogenesis. Its variant (NM_001256071.2 [RNF213]: c.14429G>A [p.Arg4810Lys, rs112735431]) was identified in a heterozygous state in 7 (9.2%) of the 76 PAH patients and represents a well-known risk factor for Moyamoya disease, a vascular disorder of the brain.3 The allele frequency for this variant is 0.7681% in the 3515 normal Japanese population according to Integrative Japanese Genome Variation Database (The genome cohort study of Tohoku Medical Megabank Organization), indicating a variant frequency ratio for idiopathic PAH relative to that in the RESEARCH LETTER