Whole-Exome Sequencing Reveals SHANK3 and CHD8 Variants in Autism Spectrum Disorder

Authors

  • Hakeemah Tuama Hazim Department of Biology, College of Science, University of Misan, Maysan, Iraq
  • Maytham Abdulkadhim Dragh Department of Biology, College of Science, University of Misan, Maysan, Iraq
  • Salah H. Faraj Department of Biology, College of Science, University of Misan, Maysan, Iraq

DOI:

https://doi.org/10.15395/mkb.v58.4867

Keywords:

Autism spectrum disorder, chromatin remodeling, neurodevelopment, synaptic transmission, whole-exome sequencing

Abstract

Autism spectrum disorder (ASD) is a complex neurodevelopmental disorder associated with synaptic dysfunction and chromatin remodeling abnormalities. Among the genes implicated in ASD, SHANK3 and CHD8 play essential roles in synaptic organization and neurodevelopmental regulation. This study aimed to investigate genetic variants in SHANK3 and CHD8 and evaluate their possible association with ASD susceptibility. A case-control study was conducted on twenty (20) participants, including ten (10) clinically diagnosed ASD patients according to DSM-5 criteria and ten (10) age- and sex-matched neurotypical controls. Whole-exome sequencing was performed using the Illumina NovaSeq platform with a mean coverage depth of 95× and more than 98% of target regions covered at ≥20×. Detected variants were annotated and analyzed for missense, splice-site, synonymous, and intronic alterations. Structural bioinformatics and protein interaction analyses were applied to assess the biological significance of the identified variants. A total of eighteen (18) variants were detected in SHANK3 and CHD8 genes. Two variants showed higher frequencies in ASD patients, including a missense variant (p.Ile320Thr) and a splice-site variant potentially affecting RNA processing. Structural modeling suggested that the p.Ile320Thr substitution may reduce SHANK3 protein stability. Protein interaction analyses indicated functional connectivity between SHANK3 and CHD8 through NRXN1, SYNGAP1, and GRIN2B pathways. In conclusion, the findings provide preliminary evidence supporting the involvement of SHANK3 and CHD8 variants in ASD pathogenesis through synaptic and chromatin-related mechanisms. Further studies with larger cohorts are recommended to validate these findings.

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Author Biography

  • Maytham Abdulkadhim Dragh, Department of Biology, College of Science, University of Misan, Maysan, Iraq

    Department of Medical Physics, College of Science, Al-Nahrain University, Baghdad, Iraq

References

Lord C, Elsabbagh M, Baird G, Veenstra-Vanderweele J. Autism spectrum disorder. Lancet. 2018;392(10146):508–20. doi:10.1016/S0140-6736(18)31129-2

Vahia VN. Diagnostic and statistical manual of mental disorders 5: a quick glance. Indian J Psychiatry. 2013;55(3):220–3. doi:10.4103/0019-5545.117131

Zwaigenbaum L, Penner M. Autism spectrum disorder: advances in diagnosis and evaluation. BMJ. 2018;361:k1674. doi:10.1136/bmj.k1674

Maenner MJ. Prevalence and characteristics of autism spectrum disorder. MMWR. 2021;70:1–16. doi:10.15585/mmwr.ss7011a1

Modabbernia A, Velthorst E, Reichenberg A. Environmental risk factors for autism: an evidence-based review of systematic reviews and meta-analyses. Mol Autism. 2017;8:13. doi:10.1186/s13229-017-0121-4

Tick B, Bolton P, Happé F, Rutter M, Rijsdijk F. . Heritability of autism spectrum disorders. J Child Psychol Psychiatry. 2016;57(5):585–95. doi:10.1111/jcpp.12499

Shiraishi T, Katayama Y, Nishiyama M, Shoji H, Miyakawa T, Mizoo T et al. The complex etiology of autism due to missense mutations of CHD8. Mol Psychiatry. 2024;29:2145–60. doi:10.1038/s41380-024-02491-y

Monteiro P, Feng G. SHANK proteins and autism. Nat Rev Neurosci. 2017;18(3):147–57. doi:10.1038/nrn.2016.183

Bernier R, Golzio C, Xiong B, Stessman HA, Coe BP, Penn O, et al. Disruptive CHD8 mutations define a subtype of autism early in development. Cell. 2014;158(2):263–76. doi:10.1016/j.cell.2014.06.017

Cotney J, Muhle RA, Sanders SJ, Liu L, Willsey AJ, Niu W, et al. The autism-associated chromatin modifier CHD8 regulates other autism risk genes during human neurodevelopment. Nat Commun. 2015;6:6404. Published 2015 Mar 10. doi:10.1038/ncomms7404

Dragh MA, Al-Allak ZS, Allami ZZG, et al. Cloning and expression of UbiA human gene using innovative methodologies for recombinant protein production in PUAST vector. Immunopathol Persa. 2025;11(1):e40643. doi:10.34172/ipp.2025.40643

Fu JM, Satterstrom FK, Peng M, Brand H, Collins RL, Dong S, et al. Rare coding variation provides insight into the genetic architecture and phenotypic context of autism. Nat Genet. 2022;54(9):1320–331. doi:10.1038/s41588-022-01104-0

Richards S, Aziz N, Bale S, Bick D, Das S, Gastier-Foster J, et al. Standards and guidelines for the interpretation of sequence variants: a joint consensus recommendation of the American College of Medical Genetics and Genomics and the Association for Molecular Pathology. Genet Med. 2015;17(5):405–24. doi:10.1038/gim.2015.30

Huang M, Qi Q, Xu T. Targeting Shank3 deficiency and paresthesia in autism spectrum disorder: A brief review. Front Mol Neurosci. 2023;16:1128974. doi:10.3389/fnmol.2023.1128974

Bae HG, Wu WC, Nip K, Gould E, Kim JH. Scn2a-linked myelination deficits and synaptic plasticity alterations drive auditory processing disorders in an ASD mouse model. Nat Commun. 2025;16(1):7109. doi:10.1038/s41467-025-62494-3

Basson MA. Neurodevelopmental functions of CHD8: new insights and questions. Biochem Soc Trans. 2024;52(1):15–27. doi:10.1042/BST20220926

Bhattacharya A, Vo DD, Jops C, Kim M, Wen C, Hervoso JL,, et al. Isoform-level transcriptome-wide association uncovers genetic risk mechanisms for neuropsychiatric disorders in the human brain. Nat Genet. 2023;55(12):2117–128. doi:10.1038/s41588-023-01560-2

Leblond CS, Cliquet F, Carton C, Huguet G, Mathieu A, Kergrohen T, et al. Both rare and common genetic variants contribute to autism in the Faroe Islands. NPJ Genom Med. 2019;4:1. doi:10.1038/s41525-018-0075-2

Weissberg O, Elliott E. The Mechanisms of CHD8 in Neurodevelopment and Autism Spectrum Disorders. Genes (Basel). 2021;12(8):1133. doi:10.3390/genes12081133

McNeill H, Woodgett JR. Signalling pathways in development. Nat Rev Mol Cell Biol. 2010;11(6):404–13. doi:10.1038/nrm2902

Dragh MA, Al-Allak ZS, Allami ZZG. HEIX1 mutation effects on endoplasmic reticulum stress, caspase activation, and JNK2 pathways. J Babol Univ Med Sci. 2025;27:e11. doi:10.22088/jbums.27.1.11

Huang C, Voglewede MM, Ozsen EN, Wang H, Zhang H. SHANK3 Mutations Associated with Autism and Schizophrenia Lead to Shared and Distinct Changes in Dendritic Spine Dynamics in the Developing Mouse Brain. Neuroscience. 2023;528:1–11. doi:10.1016/j.neuroscience.2023.07.024

Yang J, Ma G, Du X, Xie J, Wang M, Wang W, et al. Deciphering the role of Shank3 in dendritic morphology and synaptic function across postnatal developmental stages in the Shank3B KO mouse. Neurosci Bull. 2025;41(4):583–99. doi:10.1007/s12264-024-01330-y

Satterstrom FK, Kosmicki JA, Wang J, Breen MS, De Rubeis S, An JY, et al. Large-scale exome sequencing study implicates both developmental and functional changes in the neurobiology of autism. Nature. 2020;581(7809):240–5. doi:10.1038/s41586-020-2364-2

De Rubeis S, He X, Goldberg AP, Poultney CS, Samocha K, Cicek AE, et al. Synaptic, transcriptional and chromatin genes disrupted in autism. Nature. 2014;515(7526):209–15. doi:10.1038/nature13772

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Published

2026-06-30

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How to Cite

Whole-Exome Sequencing Reveals SHANK3 and CHD8 Variants in Autism Spectrum Disorder. (2026). Majalah Kedokteran Bandung, 58(2), 95-102. https://doi.org/10.15395/mkb.v58.4867