Jiajia Zhang

Prevalence and Associated Risk Factors of Dyslexic Children in a Middle-Sized City of China: A Cross-Sectional Study

Background There are many discussions about dyslexia based on studies conducted in western countries, and some risk factors to dyslexia, such as gender and home literacy environment, have been widely accepted based on these studies. However, to our knowledge, there are few studies focusing on the risk factors of dyslexia in China. Therefore, the aim of our study was to investigate the prevalence of dyslexia and its potential risk factors. Methods A cross-sectional study was conducted in Qianjiang, a city in Hubei province, China. Two stages sampling strategy was applied to randomly selected 5 districts and 9 primary schools in Qianjiang. In total, 6,350 students participated in this study and there were 5,063 valid student questionnaires obtained for the final analyses. Additional questionnaires (such as Dyslexia Checklist for Chinese Children and Pupil Rating Scale) were used to identify dyslexic children. The chi-square test and multivariate logistic regression were employed to reveal the potential risk factors to dyslexia. Results Our study revealed that the prevalence of dyslexia was 3.9% in Qianjiang city, which is a middle-sized city in China. Among dyslexic children, the gender ratio (boys to girls) was nearly 3∶1. According to the P-value in the multivariate logistic regression, the gender (P<0.01), mothers education level (P<0.01), and learning habits (P<0.01) (active learning, scheduled reading time) were associated with dyslexia. Conclusion The prevalence rate of dyslexic children in middle-sized cities is 3.9%. The potential risk factors of dyslexic children revealed in this study will have a great impact on detecting and treating dyslexic children in China as early as possible, although more studies are still needed to further investigate the risk factors of dyslexic children in China.

Genetic variant in DIP2A gene is associated with developmental dyslexia in Chinese population

Increasing evidence suggests that there is a substantial heritable component including several risk loci and candidate genes for developmental dyslexia (DD). DIP2A has been identified to be partially deleted on chromosome region 21q22.3, which cosegregates with DD. And it fits into a theoretical molecular network of DD implicated in the development of DD. Compared with some DD candidate genes that have been extensively studied (e.g., DYX1C1, DCDC2, KIAA0319, and ROBO1), very little is known about the association between candidate gene DIP2A and DD susceptibility. And given the linguistic and genetic differences between Chinese and other Western populations, it is worthwhile validating the association of DIP2A in Chinese dyslexic children. Here, we investigated two genetic variants, selected by bioinformatics analysis, in DIP2A in a Chinese population with 409 dyslexic cases and 410 healthy controls. We observed a significantly increased DD risk associated with rs2255526 G allele (OR = 1.297, 95% CI = 1.036–1.623, Padjusted = 0.023) and GG genotypes (OR = 1.833, 95% CI = 1.043–3.223, Padjusted = 0.035), compared with their wild‐type counterparts. In addition, it was marginally significantly associated with DD under the recessive model (OR = 1.677, 95% CI = 0.967–2.908, Padjusted = 0.066) and the dominant model (OR = 1.314, 95% CI = 0.992–1.741, Padjusted = 0.057). However, we found no evidence of an association of SNP rs16979358 with DD. In conclusion, this study showed that a genetic variant in the DIP2A gene was associated with increased DD risk in China.

Opposite Associations between Individual KIAA0319 Polymorphisms and Developmental Dyslexia Risk across Populations: A Stratified Meta-Analysis by the Study Population

KIAA0319 at the DYX2 locus is one of the most extensively studied candidate genes for developmental dyslexia (DD) owing to its important role in neuronal migration. Previous research on associations between KIAA0319 genetic variations and DD has yielded inconsistent results. It is important to establish a more precise estimate of the DD risk associated with these genetic variations. We carried out a meta-analysis of association studies involving KIAA0319 polymorphisms and DD risk. The results of pooled analysis indicated that none of the six investigated markers in or near the KIAA0319 gene are associated with DD. However, a stratified analysis by the study population revealed opposite associations involving KIAA0319 rs4504469 in European and Asian subgroups. The stratified analysis also showed that the KIAA0319 rs9461045 minor allele (T allele) has a protective effect in Asians. This meta-analysis has allowed us to establish the effects of specific KIAA0319 polymorphisms on DD risk with greater precision, as they vary across populations; analyzing one single nucleotide polymorphism at a time could not fully explain the genetic association for DD.

A near-infrared brain function study of Chinese dyslexic children

Recently, two findings using functional magnetic resonance imaging of dyslexic in Chinese show the left middle frontal gyrus is a crucial area associated with reading disability. The purpose of present study was to replicate the previous findings using near-infrared spectroscopy and a consonant–vowel task which engaged finer-grained phonological processing. Compared to the control group, our study showed the dyslexic children had decreased amounts of oxy-hemoglobin and total-hemoglobin in the left dorsolateral prefrontal cortex. These results supported the previous findings and indicated that phonological deficit was also the cause of dyslexia in Chinese and it might be explained by decreased activity in left dorsolateral prefrontal cortex. Our study suggests that dyslexic children have an abnormal hemodynamic pattern in the left inferior frontal gyrus and the left middle frontal gyrus, which can provide a new target for diagnosing or treating the condition with the near-infrared spectroscopy.

Neurexin gene family variants as risk factors for autism spectrum disorder

Increasing evidence suggests that abnormal synaptic function leads to neuronal developmental disorders and is an important component of the etiology of autism spectrum disorder (ASD). Neurexins are presynaptic cell‐adhesion molecules that affect the function of synapses and mediate the conduction of nerve signals. Thus, neurexins are attractive candidate genes for autism. Since gene families have greater power to reveal genetic association than single genes, we designed this case‐control study to investigate six genetic variants in three neurexin genes (NRXN1, NRXN2, and NRXN3) in a Chinese population including 529 ASD patients and 1,923 healthy controls. We found that two SNPs were significantly associated with ASD after false discovery rate (FDR) adjustment for multiple comparisons. The NRXN2 rs12273892 polymorphism T allele and AT genotype were significantly associated with increased risk of ASD (respectively: OR = 1.328, 95% CI = 1.133–1.557, P < 0.001; OR = 1.528; 95% CI = 1.249–1.868, P < 0.001). The dominant model showed the same association (OR = 1.495, 95% CI = 1.231–1.816, P < 0.001). The NRXN3 rs12879016 polymorphism played a significant role in ASD susceptibility under the dominant model (OR = 0.747, 95% CI= 0.615–0.908, P = 0.023), with the same trend detected for the G allele and GT genotype (respectively: OR = 0.811, 95% CI = 0.699–0.941, P = 0.036; OR = 0.755, 95% CI = 0.615–0.928, P = 0.035). In conclusion, this study supports the importance of two genetic variants in the neurexin gene family in ASD susceptibility in China. Autism Res 2018, 11: 37–43.

Validity and Reliability of the Dyslexia Checklist for Chinese Children

The study on developmental dyslexia (DD) has fairly matured in the past decades, even when there is a lack of a standardized and convenient instrument for dyslexia in the Chinese population. The purpose of this study was to assess the reliability and validity of the Dyslexia Checklist for Chinese Children (DCCC), which was administered to Chinese students in primary school. A total of 545 students from grades 2 through 6 were recruited in Wuhan to participate in this study. We used confirmatory factor analysis (CFA) to evaluate the structure validity of the DCCC. Concurrent validity was determined via correlations between the DCCC and the verbal comprehension index (VCI), and Chinese achievement. The reliability of the DCCC was assessed via test-retest reliability and internal consistency. The CFA suggested that the first order model with eight factors and 55 items fit the data well (RMSEA = 0.057, CFI = 0.930, and TLI = 0.925). The DCCC was negatively associated with VCI (r = −0.218) and Chinese achievement (r = −0.372). The test-retest reliability of the DCCC was 0.734, and the internal consistency of all subscales was above 0.752. The DCCC thus proved to have adequate validity and reliability to screen Chinese dyslexia among students in grades 2 through 6.

Pathways linking socioeconomic status to small-for-gestational-age (SGA) infants among primiparae: a birth cohort study in China

Objectives Evidence about the relationship between socioeconomic status (SES) and small-for-gestational-age (SGA) infants was insufficient among Chinese primiparae. In addition, factors that may mediate this relationship are poorly understood. The purpose of this study was to investigate the risk of and mediators between SES and SGA. Design Retrospective cohort study. Setting Wuhan, Hubei, China. Method Participants were recruited from patients who gave birth in the maternity care hospital of Wuhan between September 2012 and October 2014. Logistic regression models were used to estimate the association between SES and SGA. Pathway analysis was performed to examine the contribution of maternal lifestyles and pregnancy-induced hypertension syndrome (PIH) to the relationship between SES and SGA. Total effect, direct effect and indirect effect of SES on SGA were measured. Effect sizes were evaluated by unstandardised estimates (B) and standardised estimates (ß). Results Among 8737 primiparae, 927 (10.61%) pregnant women had babies with SGA. High SES was inversely associated with risk of SGA (OR 0.856; 95% CI 0.737 to 0.995) after adjustment for potential confounders. Maternal obstetric characteristics, lifestyles and PIH completely mediated SES and SGA (indirect effect: B=−0.067, 95% CI −0.108 to –0.026). The indirect effect of SES was strengthened by PIH (B=−0.029), a multivitamin supplement (B=−0.021), prepregnancy body mass index (BMI) ≥18.50 (B=−0.009) and prepregnancy BMI ≥18.50 to gestational weight gain (GWG) not below the Institute of Medicine (IOM) recommendations (B=−0.003). Conclusions Women from high SES predicted lower risk of PIH, more chances to take a multivitamin supplement during early pregnancy, keeping prepregnancy BMI ≥18.50 kg/cm2 and gaining adequate gestational weight which was not below IOM recommendations. Furthermore, lower risk of PIH, more chances to take a multivitamin supplement, prepregnancy BMI ≥18.50 kg/cm2 and GWG not below IOM recommendations were associated with a lower risk of SGA infants.

A gradient relationship between low birth weight and IQ: A meta-analysis

Multiple studies have reported that individuals with low birth weights (LBW, <2500 g) have a lower intelligence quotient (IQ) than those with normal birth weights (NBW, ≥2500 g). Based on 57 eligible individual studies including 12,137 participants, we performed a meta-analysis to estimate the association between low birth weight and individuals’ IQ scores (IQs). The pooled weight mean difference (WMD) in IQs between NBW and LBW individuals was 10 (95% CI 9.26–11.68). The WMD was stable regardless of age. No publication bias was detected. The mean IQs of the extremely low birth weight (ELBW, <1000 g), very low birth weight (VLBW, 1000–1499 g), moderately low birth weight (MLBW, 1500–2499 g) and NBW individuals were 91, 94, 99 and 104, respectively. Additionally, the WMD in IQs with NBW were 14, 10 and 7 for ELBW, VLBW, and MLBW individuals, respectively. Two studies permitted estimates of the influence of social determinants of health to the discrepancy in IQs, which was 13%. Since IQ is inherited and influenced by environmental factors, parental IQs and other factors contribute to residual confounding of the results. As the conclusion was based on population studies, it may not be applicable to a single individual.