Inherited 2q23.1 microdeletions involving the MBD5 locus

BACKGROUND: Microdeletions of 2q23.1 disrupting MBD5 and loss of function mutations of MBD5 cause MBD5‐Associated Neurodevelopmental disorders (MAND). Nearly all reported patients have been isolated cases of de novo origin. METHODS: This study investigates three families with inherited MBD5 mutations from three different Regional Genetics Centres in the UK. RESULTS: Two of the parents in the study had MBD5 deletions in a mosaic form. The parent with an MBD5 deletion in an apparently nonmosaic form has a psychiatric disorder in the absence of developmental delay or dysmorphism. CONCLUSIONS: Inherited forms of MBD5 deletions are rare, but do occur, especially in a mosaic form. The phenotypic spectrum of MAND may be wider than previously thought.