Peiquan Zhao

Exome sequencing identifies ZNF644 mutations in high myopia

Myopia is the most common ocular disorder worldwide, and high myopia in particular is one of the leading causes of blindness. Genetic factors play a critical role in the development of myopia, especially high myopia. Recently, the exome sequencing approach has been successfully used for the disease gene identification of Mendelian disorders. Here we show a successful application of exome sequencing to identify a gene for an autosomal dominant disorder, and we have identified a gene potentially responsible for high myopia in a monogenic form. We captured exomes of two affected individuals from a Han Chinese family with high myopia and performed sequencing analysis by a second-generation sequencer with a mean coverage of 30× and sufficient depth to call variants at ∼97% of each targeted exome. The shared genetic variants of these two affected individuals in the family being studied were filtered against the 1000 Genomes Project and the dbSNP131 database. A mutation A672G in zinc finger protein 644 isoform 1 (ZNF644) was identified as being related to the phenotype of this family. After we performed sequencing analysis of the exons in the ZNF644 gene in 300 sporadic cases of high myopia, we identified an additional five mutations (I587V, R680G, C699Y, 3′UTR+12 C>G, and 3′UTR+592 G>A) in 11 different patients. All these mutations were absent in 600 normal controls. The ZNF644 gene was expressed in human retinal and retinal pigment epithelium (RPE). Given that ZNF644 is predicted to be a transcription factor that may regulate genes involved in eye development, mutation may cause the axial elongation of eyeball found in high myopia patients. Our results suggest that ZNF644 might be a causal gene for high myopia in a monogenic form.

High prevalence of myopia and high myopia in 5060 Chinese university students in Shanghai.

PURPOSE Myopia is an important cause of correctable visual impairment worldwide. Genetic and environmental factors contribute to its development. The population of Chinese university students consists of approximately 30 million young people characterized by academic excellence and similar ages. To date, little is known about their refractive status. Our study is designed to investigate the prevalence of myopia in this specific population. METHODS This is a cross-sectional study of myopia among university students in Shanghai, China; 5083 students from Donghua University were enrolled. All participants first responded to a detailed questionnaire, including questions on ethnicity, birth date, and family history, and then undertook a standardized ophthalmologic examination, including visual acuity, a slit-lamp examination, and non-cycloplegic autorefraction. RESULTS The mean spherical equivalent refraction (SER) of the university students was -4.1 diopters (D). Of the subjects 95.5% were myopic (SER < -0.50 D), 19.5% were highly myopic (SER < -6.0 D), and only 3.3% were emmetropic (-0.5 D ≤ SER ≤ 0.5 D). The postgraduates were more myopic than the undergraduates (96.9% and 94.9%, respectively). Being female (-4.1 ± 2.4 D in female versus -3.8 ± 2.4 D in male subjects), of Han ethnicity (-4.1 ± 2.4 D in Han versus -3.4 ± 2.2 D in minorities), and of older age were associated with a higher probability of myopia only in the undergraduate population. CONCLUSIONS The prevalence of myopia and high myopia in this university student population was high. The refractive status of this population deserves further attention.

Genetic and functional dissection of HTRA1 and LOC387715 in age-related macular degeneration.

A common haplotype on 10q26 influences the risk of age-related macular degeneration (AMD) and encompasses two genes, LOC387715 and HTRA1. Recent data have suggested that loss of LOC387715, mediated by an insertion/deletion (in/del) that destabilizes its message, is causally related with the disorder. Here we show that loss of LOC387715 is insufficient to explain AMD susceptibility, since a nonsense mutation (R38X) in this gene that leads to loss of its message resides in a protective haplotype. At the same time, the common disease haplotype tagged by the in/del and rs11200638 has an effect on the transcriptional upregulation of the adjacent gene, HTRA1. These data implicate increased HTRA1 expression in the pathogenesis of AMD and highlight the importance of exploring multiple functional consequences of alleles in haplotypes that confer susceptibility to complex traits.

Association of HTRA1 polymorphism and bilaterality in advanced age-related macular degeneration

Single nucleotide polymorphism (SNP), rs11200638, in the promoter of HTRA1 has recently been shown to increase the risk for AMD. In order to investigate the association of this HTRA1 polymorphism and the bilaterality of AMD, we genotyped rs11200638 in control, unilateral, and bilateral advanced AMD patients. The A allele for SNP rs11200638 in HTRA1, was significantly more prevalent in bilateral wet AMD and GA patients than in unilateral groups (p=.02 and p=.03, respectively). The homozygote odds ratios of bilateral wet AMD and GA are significantly greater than those seen in unilateral groups (twofold and threefold increase, respectively). This finding is consistent with the role of HTRA1 in AMD pathogenesis and will help aid in the clinical management and prognosis of AMD patients.

HTRA1 variant increases risk to neovascular age-related macular degeneration in Chinese population.

Age-related macular degeneration (AMD) is a leading cause of irreversible visual impairment in the world. Advanced AMD can be divided into wet AMD (choroidal neovascularization) and dry AMD (geographic atrophy, GA). Drusen is characterized by deposits in the macula without visual loss and is an early AMD sign in the Caucasian population. rs11200638 in the promoter of HTRA1 has recently been shown to increases the risk for wet AMD in both Caucasian and Hong Kong Chinese populations. In order to replicate these results in a different cohort, we genotyped rs11200638 for 164 Chinese patients (90 wet AMD and 74 drusen) and 106 normal controls in a Han Mainland Chinese cohort. The genotypes were compared using chi square analysis for an additive allelic model. rs11200638 was significantly associated with wet AMD (p=5.00x10(-12)). Unlike in the Caucasian population, the risk allele of rs11200638 was not associated with drusen in our Chinese population. These findings confirm the association of HTRA1 with wet AMD.

A genome-wide meta-analysis identifies two novel loci associated with high myopia in the Han Chinese population

High myopia, highly prevalent in the Chinese population, is a leading cause of visual impairment worldwide. Genetic factors play a critical role in the development of this visual disorder. Genome-wide association studies in recent years have revealed several chromosomal regions that contribute to its progression. To identify additional genetic variants for high myopia susceptibility, we used a genome-wide meta-analysis to examine the associations between the disease and 286 031 single-nucleotide polymorphisms (SNPs) in a combined cohort of 665 cases and 960 controls. The most significant SNPs (n = 61) were genotyped in a replication cohort (850 cases and 1197 controls), and 14 SNPs were further tested through genotyping in two additional validation cohorts (combined 1278 cases and 2486 controls). As a result of this analysis, four SNPs reached genome-wide significance (P < 2.0 × 10(-7)). The most significantly associated SNP, rs2730260 [overall P = 8.95 × 10(-14); odds ratio (95% CI) =1.33 (1.23-1.44)], is located in the VIPR2 gene, which is located in the MYP4 locus. The other three SNPs (rs7839488, rs4395927 and rs4455882) in the same linkage disequilibrium block are located in the SNTB1 gene, with -P values ranging from 1.13 × 10(-8) to 2.13 × 10(-11). The VIPR2 and SNTB1 genes are expressed in the retina and the retinal pigment epithelium and have been previously reported to have potential functions for the pathogenesis of myopia. Our results suggest that variants of the VIPR2 and SNTB1 genes increase susceptibility to high myopia in Han Chinese.

Screening for Retinopathy of Prematurity in China: A Neonatal Units–Based Prospective Study

PURPOSE To analyze the incidence and severity of retinopathy of prematurity (ROP) in China, and to explore the workload implications of applying different criteria. METHODS A prospective, neonatal units-based study undertaken in two tertiary level hospitals in Shanghai, China, from January 1, 2010 to December 31, 2012. All infants with birth weight (BW) of 2000 g or less and/or gestational age (GA) of 34 weeks or less were screened for ROP. Retinopathy of prematurity was classified using the international classification, and was treated in accordance with the recommendations of the Early Treatment for Retinopathy of Prematurity Cooperative Group. RESULTS A total of 2825 (93.7%) of 3014 eligible infants were screened, and ROP was diagnosed in 503 infants (17.8%). One hundred ninety-one infants (6.8%) had type 1 or worse ROP and were treated with laser or vitrectomy. The mean GA of ROP patients was 29.9 ± 2.1 weeks and their mean BW was 1425 ± 266 g. Infants who needed treatment for ROP had a mean GA of 29.3 ± 2.1 weeks and mean BW of 1331 ± 330 g. Among these treated infants, 18 infants (9.4%) exceeded the United Kingdoms (UK) screening criteria, and 28 (14.7%) exceeded the criteria used in the United States (US). If narrower criteria, as in GA less than or equal to 33 weeks and/or BW less than or equal to 1750 g were adopted, almost 16.9% fewer infants would not have been examined, with no infant missing treatment. CONCLUSIONS Larger, older infants are at risk in China and screening criteria used in the US and UK may not be suitable for China. Further population-based studies are recommended to determine the necessity of modifying the current ROP screening protocol.

Prevalence and associations of epiretinal membrane in an elderly urban Chinese population in China: the Jiangning Eye Study

Aims To describe the prevalence and associations of epiretinal membrane (ERM) in an elderly urban Chinese population in China. Methods A population-based cross-sectional study was conducted using a cluster random sample of residents aged 50 years or older living in the Jiangning Road Sub-district, Shanghai, China. All participants underwent a standardised interview and comprehensive eye examinations, including digital retinal photography and spectral domain optical coherence tomography (SD-OCT) examinations of both eyes between November 2012 and February 2013. ERM was identified and classified as either cellophane macular reflex (CMR) or preretinal macular fibrosis (PMF) based on the fundus photography and OCT features. Results Of the 2044 subjects who participated (82.5% response rate), 2005 had fundus photographs and OCT results of sufficient quality for grading of ERM signs. ERM was present in 8.4% of participants, including 5.0% with CMR and 3.4% with PMF. After age and gender standardisation to the 2010 Chinese census population, the prevalence rate of ERM in mainland Chinese individuals of 50 years of age or older was estimated to be 7.3%. After adjusting for age and/or gender, idiopathic ERM was positively associated with age (OR, 1.06; 95% CI 1.04 to 1.08), female gender (OR 1.67, 95% CI 1.16 to 2.40), myopia (OR 2.21, 95% CI 1.51 to 3.22) and hyperlipaemia (OR 1.80, 95% CI 1.04 to 3.12). Conclusions The prevalence of ERM in elderly urban Chinese was similar to that in Caucasians. Risk factors for idiopathic ERM were older age, female gender, myopia and hyperlipaemia.

A Genetic Variant in the SKIV2L Gene Is Significantly Associated With Age-Related Macular Degeneration in a Han Chinese Population

PURPOSE Previous studies have shown that genetic variants in the complement component 2 (C2)/complement factor B (BF) gene are associated with AMD in Caucasians, but not in Han Chinese. Recent studies have indicated that genetic variants in the neighboring superkiller viralicidic activity 2-like (SKIV2L) gene showed significant association with AMD. We conducted this study to investigate whether genetic variants in the SKIV2L gene are associated with AMD in a Han Chinese population. METHODS Thirteen single nucleotide polymorphisms (SNPs) in the C2-BF-RDBP-SKIV2L-STK19 region were genotyped by the SNaPshot method in a cohort composed of 449 patients with choriodal neovascularization (CNV) AMD and 1025 healthy controls of Han Chinese descent. RESULTS Among the SNPs genotyped, P values of seven SNPs were less than 0.05; however, only rs429608 was found to be significantly associated with AMD after correction for multiple testing. The minor allele (A) frequency of rs429608 was 0.050 in cases and 0.089 in controls, and the P value was 3.76 × 10(-4) (0.00489 after Bonferroni correction), with an odds ratio of 0.55 (95% confidence interval, 0.40-0.77). The SKIV2L gene was expressed in the human RPE, retina, and D407 (human RPE) cells, and in mouse retinas and RPE. CONCLUSIONS We demonstrated that the rs429608 genetic variant in the SKIV2L gene was significantly associated with AMD in a Han Chinese population. SKIV2L may play an important role in the development of AMD.

Early vitreoretinal surgery on vascularly active stage 4 retinopathy of prematurity through the preoperative intravitreal bevacizumab injection

Purpose:  To evaluate the effect of early vitreoretinal surgery on vascularly active stage 4 ROP through the preoperative use of intravitreal bevacizumab.