Nasal Cytology and Usher Syndrome Diagnosis

Abstract

Abstract: : Purpose: Diagnosis of molecular subtypes of Usher syndrome is an obvious pre–requisite to identification of patient pools for future therapeutic intervention. There are at least seven genes responsible for Usher syndrome type 1, the most common is USH1b, which encodes myosin VIIa. Earlier studies predicted the presence of myosin VIIa in cilitated cells. In this study we ask whether immunostaining for myosin VIIa in ciliated cells can be diagnostic for USH1b. Methods: Ciliated nasal epithelial cells were scraped from the inferior turbinate and subjected to immunofluorescence immunostaining using antibodies specific for myosin VIIa. Both normal and USH 1b patients with confirmed double null mutations were tested. Results: Ciliated nasal epithelial cells were immunopositive for myosin VIIa. The immunostaining pattern was highly specific, localizing to a structurally distinct supra nuclear band opposite the ciliary structure. Immunostaining in patients with confirmed double null mutations was absent. Conclusions: Immunostaining ciliated nasal epithelial cells for myosin VIIa provides an inexpensive, simple, reliable, and non–invasive means of diagnosing patients with Usher syndrome 1b.

Keywords: immunohistochemistry • clinical research methodology • retinal degenerations: hereditary