Joshua Hodgson, Lidia Ruiz- Llorente, Jamie McDonald, Oliver Quarrell, Kelechi Ugonna, James Bentham, Rebecca Mason, Jennifer Martin, David Moore, Katie Bergstrom, Pinar Bayrak- Toydemir, Whitney Wooderchak-Donahue, Nicholas W. Morrell, Robin Condliffe, Carmelo Bernabeu, Paul D. Upton
University of Cambridge. Centro de Investigaciones Biológicas Margarita Salas, Consejo Superior de Investigaciones Científicas (CSIC), and Centro de Investigación Biomédica en Red de Enfermedades Raras. University of Alcalá, Madrid. University of Utah. Sheffield Children’s Hospital. Leeds Children’s Hospital. Western General Hospital. Baylor College of Medicine and Texas Children’s Hospital. Royal Hallamshire Hospital.
United Kingdom, Spain and United States
Molecular Genetics and Genomic Medicine
Mol Genet Genom Med 2021; 9:
DOI: 10.1002/mgg3.1685
Abstract
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.
Category
Class I. Heritable Pulmonary Hypertension
Pulmonary Arteriovenous Malformations
Genetic Factors Associated with Pulmonary Vascular Disease
Age Focus: Pediatric Pulmonary Vascular Disease
Fresh or Filed Publication: Filed (PHiled). Greater than 1-2 years since publication
Article Access
Free PDF File or Full Text Article Available Through PubMed or DOI: Yes