Association of <i>SIX1-SIX6</i> polymorphisms with peripapillary retinal nerve fibre layer thickness in children.

Abstract

Association of <i>SIX1-SIX6</i> variants with peripapillary retinal nerve fibre layer (p-RNFL) thickness had been reported in adults. This study aimed to investigate these associations in children, with further explorations by spatial, age and sex stratifications. 2878 school children aged between 6 and 9 years were enrolled from the Hong Kong Children Eye Study. Three single-nucleotide polymorphisms (SNPs) at the <i>SIX1-SIX6</i> locus were genotyped. The association of each SNP with p-RNFL thickness (including global and sectoral thickness) were evaluated using multiple linear regression. SNPs rs33912345 (p=7.7×10^-4) and rs10483727 (p=0.0013) showed significant associations with temporal-inferior p-RNFL thickness. The C allele of rs33912345 was associated with a thinner temporal-inferior p-RNFL by an average of 2.44 µm, while rs10483727-T was associated with a thinner temporal-inferior p-RNFL by 2.32 µm. The association with temporal-inferior p-RNFL was the strongest in the 8-9 year-old group for rs33912345 (p=5.2×10^-4) and rs10483727 (p=3.3×10^-4). Both SNPs were significantly associated with temporal-inferior p-RNFL thickness in boys (p<0.0017), but not in girls (p>0.05). In contrast, rs12436579-C (β=1.66; p=0.0059), but not rs33912345-C (β=1.31; p=0.052) or rs10483727-T (β=1.19; p=0.078), was nominally associated with a thicker nasal-inferior p-RNFL. Both rs33912345 and rs10483727 at <i>SIX1-SIX6</i> were associated with p-RNFL thickness in children, especially at the temporal-inferior sector, with age-dependent and sex-specific effects. SNP rs12436579 was associated with nasal-inferior p-RNFL thickness. Our findings suggested a role of <i>SIX1-SIX6</i> in RNFL variation during neural retina development in childhood.