NCIt definition : An autosomal recessive sub-type of Usher syndrome caused by homozygous or compound
heterozygous mutation(s) in the ADGRV1 gene, encoding adhesion G protein-coupled receptor
V1. It may also result from biallelic digenic mutation(s) in ADGRV1 and PDZD7, which
encodes PDZ domain-containing protein 7.;