ABSTRACT
The aetiology of developmental dyslexia (DD) is complex; although candidate genes have been suggested, the molecular mechanism and risk factors remain unknown. The KIAA0319 gene is functionally related to neuronal migration and axon growth, and several studies have examined associations between KIAA0319 polymorphisms with DD, but the results remain inconsistent. The sample size affects the results of meta-analysis. The aim of this meta-analysis was to clarify the effect of KIAA0319 polymorphisms on dyslexia susceptibility according to the available evidence. All eligible case–control and transmission/disequilibrium test (TDT) studies published until March 2018 were identified by searchingMedline, PubMed, Embase, Web of Science and Chinese Biomedical Database, limited to Chinese and English language papers. Pooled odds ratios and 95% confidence intervals were calculated using STATS package v12.0. A total of 11 related studies, including 3130 cases of dyslexia and 3460 healthy control subjects, as well as four TDT studies with 842 families were included in our meta-analysis. The results indicated that the polymorphisms rs4504469, rs2038137, rs2179515, rs3212236, rs6935076, rs9461045, rs2143340 and rs761100 have no association between the polymorphisms and dyslexia risk. Three subgroup meta-analyseswere performed according to the study design, country and population. The stratified analysis revealed that the KIAA0319 rs4504469 minor allele was a risk allele t in the TDT subgroup, rs3212236 minor allele was a risk allele t in the UK subgroup and rs6935076 minor allele was a risk allele t in the Canada subgroup. Further studies with larger sample sizes that assess gene–gene and gene–environment interactions are required. The sample size of our study is larger than that of the previous studies, and the results are different from those of the previous studies.We have synthesized all the current studies on KIAA0319 and obtained reliable results.