Biology subjects

Wong, C. C. Y.

Publications and source records attributed to Wong, C. C. Y..

3 recordsLinked to original sources

bioRxiv2025

Epigenome-wide analysis reveals novel DNA methylation signatures significantly associated with the infant pupillary light reflex, a candidate intermediate phenotype for autism.

Autism is a highly heterogeneous neurodevelopmental condition, currently diagnosed based on behavioural characteristics. Candidate early intermediate phenotypes, such as the Pupillary Light Reflex (PLR), a reflexive constriction of the pupil in response to increased optical luminance, may provide insights into etiological factors and potential biomarkers, such as DNA methylation (DNAm), involved in the emergence of autism. We conducted epigenome-wide DNAm association analyses of 9-, 14-, 24-month PLR onset latency and constriction amplitude in a sample of 51 infants enriched for autism family history, using buccal DNA collected at 9-months. Our epigenome-wide analysis (EWAS) identified four stringently significant differentially methylated probes (p < 2.4 x 10-7) associated with cross-section PLR latency measurements at 14- and 24-months, and with 14-to 24-month PLR latency developmental change. Differentially methylated probes associated with PLR amplitude were identified, but at a less stringent discovery threshold (p < 5 x 10-5). Our region analyses identified several significant differentially methylated regions associated with both PLR latency and amplitude Downstream exploratory pathway analysis identified enrichment for multiple developmental biological processes, as well as several susceptibility genes to autism and related neurodevelopmental conditions including NR4A2, HNRNPU and NAV2. Our findings provide novel insight into the role of DNAm in PLR development and illuminate biological mechanisms underpinning altered PLR in infancy in emerging autism.

neuroscience↗

bioRxiv2019

Integrative genomics identifies a convergent molecular subtype that links epigenomic with transcriptomic differences in autism

Autism spectrum disorder (ASD) is a phenotypically and genetically heterogeneous neurodevelopmental disorder. Despite this heterogeneity, previous studies have shown patterns of molecular convergence in post-mortem brain tissue from autistic subjects. Here, we integrate genome-wide measures of mRNA expression, miRNA expression, DNA methylation, and histone acetylation from ASD and control brains to identify a convergent molecular subtype of ASD with shared dysregulation across both the epigenome and transcriptome. Focusing on this convergent subtype, we substantially expand the repertoire of differentially expressed genes in ASD and identify a component of upregulated immune processes that are associated with hypomethylation. We utilize eQTL and chromosome conformation datasets to link differentially acetylated regions with their cognate genes and identify an enrichment of ASD genetic risk variants in hyperacetylated noncoding regulatory regions linked to neuronal genes. These findings help elucidate how diverse genetic risk factors converge onto specific molecular processes in ASD.

genomics↗

bioRxiv2019

Heritability of skewed X-inactivation in female twins is tissue-specific and dependent on age

To balance the X-linked transcriptional dosages between the sexes, one of the two X-chromosomes is randomly selected to be inactivated in somatic tissues of female placental mammals. Non-random, or skewed X-chromosome inactivation (XCI) toward one parental X has been observed in female somatic tissues, and this skewing effect has been associated with several complex human traits. However, the extent of the influence of genetic and environmental factors on XCI skewing is largely unknown. Here, we use RNA-seq and DNA-seq data taken from a large cohort of female twins to quantify the degree of skewing of XCI (DS) in multiple tissues and to study the relationship of XCI with age, genetic factors and complex traits. We show that the XCI patterns are highly tissue-specific with a higher prevalence of skewed XCI in blood-derived tissues than in fat or skin tissue. We also show that the DS in blood-derived tissues is associated with age and that the acquired DS occurs uniquely in blood-derived tissues with an inflection point at approximately 55 years of age. Heritability analysis indicates that the heritability of DS is both age and tissue specific; DS is heritable in blood tissue of females >55 years-old (h2 = 0.34) but is not heritable in blood tissues of females <55 years-old (h2 = 0), nor in skin and fat tissues at any age. We find a positive association between the DS and smoking status in blood tissues of older females (P = 0.02). The high tissue specificity of XCI patterns in human indicates the existence of tissue-specific mechanisms influencing XCI patterns, including genetic and environmental factors. We conclude that the heritability of XCI skewing in blood-derived tissues is dependent on age, representing a Gene x Age interaction that can shift the functional allelic dosage of an entire chromosome in a tissue-restricted manner.

genetics↗