Pinar Bayrak-Toydemir, Lidia Ruiz-Llorente, Oliver Quarrell, Katie Bergstrom, Jamie McDonald, Robin Condliffe, Nicholas W. Morrell, Kelechi Ugonna, Rebecca Mason, Jennifer M. Martin, David Moore, Carmelo Bernabeu, Paul D. Upton, Whitney Wooderchak-Donahue, Joshua Hodgson, James R. Bentham, Hodgson, Joshua [0000-0001-8423-0935], Ruiz-Llorente, Lidia [0000-0003-1430-9618], McDonald, Jamie [0000-0001-9939-7922], Quarrell, Oliver [0000-0002-3818-9051], Martin, Jennifer [0000-0002-7697-7438], Moore, David [0000-0001-9308-5741], Bergstrom, Katie [0000-0002-0353-2278], Bayrak-Toydemir, Pinar [0000-0001-9381-2478], Wooderchak-Donahue, Whitney [0000-0002-9358-7466], Morrell, Nicholas W [0000-0001-5700-9792], Condliffe, Robin [0000-0002-3492-4143], Bernabeu, Carmelo [0000-0002-1563-6162], Upton, Paul D [0000-0003-2716-4921], Apollo - University of Cambridge Repository, British Heart Foundation, Consejo Superior de Investigaciones Científicas (España), Centro de Investigación Biomédica en Red Enfermedades Raras (España), Hodgson, Joshua, Ruiz-Llorente, Lidia, McDonald, Jamie, Quarrell, Oliver, Martin, Jennifer, Moore, David, Bergstrom, Katie, Bayrak-Toydemir, Pinar, Wooderchak-Donahue, Whitney, Morrell, Nicholas W., Condliffe, Robin, Bernabéu, Carmelo, Upton, Paul D., Morrell, Nicholas W. [0000-0001-5700-9792], Bernabéu, Carmelo [0000-0002-1563-6162], Upton, Paul D. [0000-0003-2716-4921], Morrell, Nicholas [0000-0001-5700-9792], and Upton, Paul [0000-0003-2716-4921]
13 p.-3 fig.-1 tab., Background: Disrupted endothelial BMP9/10 signaling may contribute to the pathophysiology of both hereditary hemorrhagic telangiectasia (HHT) and pulmonary arterial hypertension (PAH), yet loss of circulating BMP9 has not been confirmed in individuals with ultra-rare homozygous GDF2 (BMP9 gene) nonsense mutations. We studied two pediatric patients homozygous for GDF2 (BMP9 gene) nonsense mutations: one with PAH (c.[76C>T];[76C>T] or p.[Gln26Ter];[Gln26Ter] and a new individual with pulmonary arteriovenous malformations (PAVMs; c.[835G>T];[835G>T] or p.[Glu279Ter];[Glu279Ter]); both with facial telangiectases., Methods: Plasma samples were assayed for BMP9 and BMP10 by ELISA. In parallel, serum BMP activity was assayed using an endothelial BRE-luciferase reporter cell line (HMEC1-BRE). Proteins were expressed for assessment of secretion and processing., Results: Plasma levels of both BMP9 and BMP10 were undetectable in the two homozygous index cases and this corresponded to low serum-derived endothelial BMP activity in the patients. Measured BMP9 and BMP10 levels were reduced in the asymptomatic heterozygous p.[Glu279Ter] parents, but serum activity was normal. Although expression studies suggested alternate translation can be initiated at Met57 in the p.[Gln26Ter] mutant, this does not result in secretion of functional BMP9., Conclusion: Collectively, these data show that homozygous GDF2 mutations, leading to a loss of circulating BMP9 and BMP10, can cause either pediatric PAH and/or "HHT-like" telangiectases and PAVMs. Although patients reported to date have manifestations that overlap with those of HHT, none meet the Curaçao criteria for HHT and seem distinct from HHT in terms of the location and appearance of telangiectases, and a tendency for tiny, diffuse PAVMs., This study was supported by British Heart Foundation Grant/Award Numbers: FS/15/62/323032, RG/13/4/30107, and RG/19/3/34265; Consejo Superior de Investigaciones Científicas (CSIC) Grant/Award Number: 201920E022; Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER) Grant/ Award Numbers: ISCIII-CB06/07/0038 and CNV-234-PRF-360.