PYGO2 and mandibulofacial dysostosis: Zhang et al. (2010) previously reported copy number variance of VWA1 and PYGO2 in a patient presenting with mandibulofacial dysostosis and microtia. At that time, VWA1 was suspected, but not confirmed, to be among the candidate genes responsible for the abnormal phenotype. Considering the low incidence of HFM, the fact that the mutation in was found in unrelated sporadic case and a five-generation pedigree reinforces the validity of the conclusion that the c.G905A:p.R302Q mutation in VWA1 is a likely pathogenic mutation for HFM.