KLK1 and pulmonary arterial hypertension: In a final analysis, the entire PAH Biobank cohort was screened for rare deleterious variants in KLK1 and GGCX; twelve cases carried KLK1 variants (all European), whereas 28 cases carried GGCX variants (19 European, six African, three Hispanic), accounting for ~0.4% and ~0.9% of PAH Biobank cases, respectively.