Which genetic disorder is the most common single-gene cause of autism?

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Multiple Choice

Which genetic disorder is the most common single-gene cause of autism?

Fragile X syndrome is the most common single-gene cause of autism. It arises from a CGG repeat expansion in the FMR1 gene on the X chromosome. When the repeat expands beyond a certain length, the gene is silenced by methylation, leading to reduced or absent production of the FMRP protein that helps regulate synaptic development. This disruption contributes to autistic features and learning difficulties seen in Fragile X. Although tuberous sclerosis (mutations in TSC1 or TSC2) and certain deletions like 22q11.2 can be associated with autism, they are less common as single-gene sources of autism compared with Fragile X. Prader-Willi can also involve neurodevelopmental issues but is not the most frequent single-gene autism contributor among these options.

Fragile X syndrome is the most common single-gene cause of autism. It arises from a CGG repeat expansion in the FMR1 gene on the X chromosome. When the repeat expands beyond a certain length, the gene is silenced by methylation, leading to reduced or absent production of the FMRP protein that helps regulate synaptic development. This disruption contributes to autistic features and learning difficulties seen in Fragile X.

Although tuberous sclerosis (mutations in TSC1 or TSC2) and certain deletions like 22q11.2 can be associated with autism, they are less common as single-gene sources of autism compared with Fragile X. Prader-Willi can also involve neurodevelopmental issues but is not the most frequent single-gene autism contributor among these options.

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