Sequence variations of GRM6 in patients with high myopia.
OBJECTIVE
Mutations in the glutamate receptor metabotropic 6 gene (GRM6) have been identified in patients with congenital stationary night blindness (CSNB1B). High myopia is usually observed in CSNB1B patients. This study tested if any mutations in GRM6 were solely responsible for high myopia.


METHODS
DNA was prepared from the venous leukocytes of 96 Chinese patients with high myopia (refraction of spherical equivalent of at least -6.00 diopters [D]) and 96 controls (refraction of spherical equivalent between -0.50 D and +2.00 D with normal visual acuity). The coding regions and adjacent intronic sequence of GRM6 were amplified by a polymerase chain reaction (PCR) and then analyzed by cycle sequencing. Detected variations were evaluated in normal controls by heteroduplex-single-strand-conformation (SSCP) polymorphism analysis or restriction fragment polymorphism (RFLP).


RESULTS
Four novel variations predicted to have potential functional changes were identified: c.67-82delCAGGCGGGCCTGGCGCinsT (p.Gln23_Arg28delinsCys), c.858-5a>g (r.spl?), c.1172G>A (p.Arg391Gln), and c.1537G>A (p.Val513Met). Except for c.1172G>A, the other three were not detected in the 96 controls. In addition, five rare variations-(c.72G>A, c.504+10g>t, c.726-50g>c, c.1359C>T, and c.1383C>T)-and one common variation (c.2437-6g>a) without predicted functional consequences and nine known single nucleotide polymorphisms (SNPs) were also detected.


CONCLUSIONS
Three novel variations with potential functional consequences were identified in the GRM6 of patients with high myopia, suggesting a potential role in the development of myopia in rare cases.
Xu
Xiaoyu
X
State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, China.
Li
Shiqiang
S
Xiao
Xueshan
X
Wang
Panfeng
P
Guo
Xiangming
X
Zhang
Qingjiong
Q
D001483:Base Sequence; D004252:DNA Mutational Analysis; D006801:Humans; D008969:Molecular Sequence Data; D009154:Mutation / Q000235:genetics*; D009216:Myopia / Q000235:genetics*; D012150:Polymorphism, Restriction Fragment Length; D018807:Polymorphism, Single-Stranded Conformational; D018094:Receptors, Metabotropic Glutamate / Q000235:genetics*
D018094:Receptors, Metabotropic Glutamate; C113897:metabotropic glutamate receptor 6