Multiple sequence variants in hereditary hemorrhagic telangiectasia cases: illustration of complexity in molecular diagnostic interpretation.

Hereditary hemorrhagic telangiectasia is an autosomal dominant disease caused by mutations in the ACVRL1 and ENG genes characterized by arterio-venous malformations and telangiectases. Over 700 mutations have been described in these two genes, and missense mutations are common. We describe 10 cases in which more than one potentially pathogenic mutation was identified.