PDZD7 and Usher syndrome: This report retrospectively analyses the clinical and genetic data of 21 consecutive Italian patients from 17 unrelated families affected by Usher syndrome undergoing genetic analysis by targeted NGS of 11 genes (MYO7A, CDH23, PCDH15, USH1C, USH1G, USH2A, ADGVR1, DFNB31, CLRN1, PDZD7, HARS).