MUC1 Gene Polymorphisms in Patients With Dry Eye Disease

Abstract

Purpose: : We reported that the frequency of non-Sjogren's aqueous deficient dry eye patients expressing only the MUC1/A splice variant may be lower than a normal control group (Imbert et al Exp.Eye Res. 83, 493-501, 2006). The present study was performed to determine whether expression of MUC1 splice variants was significantly different in patients with evaporative dry eye disease and non-Sjogren's aqueous deficient dry eye as compared with normal controls.

Methods: : Twenty one evaporative dry eye patients were identified as having ocular surface staining in the presence of reduced tear break up time (TBUT <7 secs), normal tear meniscus (>0.9 mm) and meibomian gland obstruction. Thirty two non-Sjogren's aqueous deficient dry eye patients were identified as having both tear deficiency and ocular surface staining. Thirty normal control subjects were age and gender matched. Genomic DNA was harvested from buccal swabs and used for single nucleotide polymorphism (SNP) analysis of the SNP that has previously been shown to control the MUC1/A and MUC1/B splicing event (rs4072037). Statistical analysis was performed by a 2 x 3 Fisher's exact test.

Results: : The MUC1 SNP genotype frequency of the normal control group was statistically different from the evaporative dry eye group (P = 0.01) as well as from the non-Sjogren's aqueous deficient dry eye group (P = 0.02). However, when the two dry eye groups were compared with each other, they were not significantly different (P = 0.09).

Conclusions: : The etiology of evaporative dry eye and non-Sjogren's aqueous deficient dry eye are known to be different. However, our results suggest that these subtypes of dry eye disease may share a common mechanism or factor related to MUC1 genotypic differences that affects susceptibility to ocular surface damage. Mechanisms influencing ocular surface damage and protection in different types of dry eye disease warrant further investigation.

Keywords: cornea: surface mucins • cornea: tears/tear film/dry eye • cornea: epithelium