INTU-related oral-facial-digital syndrome type VI: A confirmatory report

Oral-facial-digital (OFD) syndromes are a subgroup of ciliopathiesdistinguished by the co-occurrence of hamartomasand/or multiple frenula of the oral region and digital anomalies. Several clinical forms of OFD are distinguished by their associated anomalies and/or inheritance patterns, and at least 20 genetic types of OFD have been delineated. We describe here a child with preaxial and postaxial polydactyly, lingual hamartoma, a congenital heart defect, delayed development and cerebellar pedunclesdisplaying the molar tooth sign. Whole exome sequencingand SNP arrayidentified compound heterozygous variants in the INTU gene, which encodes a protein involved in the positioning of the ciliary basal body. INTU is a subunit of the CPLANE multiprotein complexessential for the assembly of IFT-A particles and intraflagellar transport. This report of a second patient with INTU-related OFD and the further delineation of its neuroimaging and skeletal phenotype now allow INTU-related OFD to be classified within the OFD VI group. Patients display a phenotype similar to that of mice with a hypomorphic mutation of Intu, but with the addition of a heart defect.