The abundant and almost exclusive expression of OCP-II protein in the mammalian cochlea has fuelled speculation that mutations in the OCP2 gene may result in inherited forms of hearing impairment. We have identified several human sequences related to OCP2 and sublocalised three of these OCP2 related loci to 4q12-p14 or 4p16.2-pter, 5q15-q21.3 and 7p22-q22 by PCR. 2 YACs with sequence consistent with the chromosome 7 locus were also used for FISH analysis and hybridised to chromosome 7q11. Our data suggest that the cytogenetic localisations of these OCP2 related sequences do not correlate with the precise chromosomal positions of deafness loci so far identified.