Purpose: The small leucine-rich repeat proteins (SLRPs) are involved in organizing the collagen fibrils of the sclera and vitreous. The shape of the eyeball is determined by the sclera and vitreous, so defects in SLRP family members may contribute to myopia. The purpose of this study was to test whether mutations in the two members of the class III SLRPs, opticin (OPTC) and dermatan sulfate proteoglycan 3 (EPYC), are responsible for high myopia.
Methods: DNA was prepared from venous leukocytes of 93 patients with high myopia (refraction of spherical equivalent <or=-6.00D) and 96 controls (refraction of spherical equivalent between -0.50D and +1.00D). The coding regions and adjacent intronic sequences of OPTC and EPYC were amplified by the polymerase chain reaction (PCR), and the products were then analyzed by cycle sequencing. The detected variations were further evaluated in normal controls and available family members by a heteroduplex-single strand conformation polymorphism (heteroduplex-SSCP) analysis or sequencing.
Results: Two substitutions in OPTC, including c.491G>T and c.803T>C, were identified. The c.491G>T mutation (p.Arg164Leu), a novel heterozygous variation, was detected in one of the 93 patients but in none of the 96 controls. The c.803T>C mutation (p.Pro267Leu), a known polymorphism, was detected in 22 of the 93 patients and in 15 of 48 controls. No variation was observed in EPYC.
Conclusions: Only one novel variation in OPTC was detected in a Chinese patient with high myopia. Our results imply that OPTC and EPYC are unlikely to play a major role in high myopia.