PCDH15 and Usher syndrome type 1: Here, we describe two Hutterite families from northern Alberta with Usher syndrome type I who did not carry a mutation in exon 10 of PCDH15 but did carry a mutation in exon 3 of the myosin VIIA (MYO7A) gene, providing evidence of genetic heterogeneity in Alberta Hutterites with Usher syndrome type I.