SLC26A4 and Waardenburg syndrome: In the calculation of diagnostic rate, 22 undiagnosed patients with characteristic phenotypes which are highly correlated to the HHL were excluded from the undiagnosed patient group (392), including 18 patients with enlarged vestibular aqueduct carrying one pathogenic variant in SLC26A4, three patients diagnosed as Waardenburg syndrome, and one case with inner malformation of IP-III.