Distribution and heritability of intraocular pressure in chinese children: the Guangzhou twin eye study.
OBJECTIVE
To assess the distribution and heritability of intraocular pressure (IOP) in Chinese children.


METHODS
Twins aged 8 to 16 years were recruited from the Guangzhou Twin Registry. IOP was measured in each twin and co-twin together, with a handheld tonometer by the same operator. Zygosity was determined based on genotyping with 16 polymorphic markers in all same-sex twin pairs. Heritability was estimated with a univariate variance component model.


RESULTS
Four hundred seventy-three twin pairs (309 monozygotic [MZ] and 164 dizygotic [DZ] twins) were available for data analyses. The mean IOP was 14.2 (SD 2.3) mm Hg. Neither age nor sex was correlated with IOP. Phenotypic correlation was 0.68 (95% confidence interval [CI], 0.62-0.74) in MZ twins and 0.40 (95% CI, 0.26-0.52) in DZ twins. A genetic model involving additive genetic and unique environmental effects was the best fit. Heritability was estimated as 66.5% (95% CI, 60.6%-71.6%).


CONCLUSIONS
IOP is not correlated with age and sex in young children. Similar to the European population, the variation of IOP in healthy Chinese children is mainly attributable to additive genetic effects.
Zheng
Yingfeng
Y
State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, People's Republic of China.
Xiang
Fan
F
Huang
Wenyong
W
Huang
Guofu
G
Yin
Qiuxia
Q
He
Mingguang
M
D000293:Adolescent; D017677:Age Distribution; D044466:Asian People / Q000235:genetics*; D002648:Child; D002681:China / Q000453:epidemiology; D005260:Female; D005838:Genotype; D006801:Humans; D007429:Intraocular Pressure / Q000235:genetics*; D008297:Male; D019655:Quantitative Trait, Heritable; D012042:Registries; D017678:Sex Distribution; D014065:Tonometry, Ocular; D014429:Twins, Dizygotic; D014430:Twins, Monozygotic