GDF2 and idiopathic pulmonary arterial hypertension: Further evidence came from the NBR study which identified associations between rare heterozygous missense (n = 7) and frameshift variants (n = 1) in adult-onset IPAH (88% European) [24]; additionally, Hodgson et al. [115] identified two patients with large deletions encompassing the GDF2 locus and several neighbouring genes.