Autism spectrum disorder (ASD) is a complex neurodevelopmental disorder that affects communication, social interaction, and behavior. Scientists believe that both genetic and environmental factors contribute to the development of ASD.

In recent years, researchers have identified several genes that are associated with an increased risk of developing autism. In this article, we will discuss some of the most commonly found autism-associated genes in human DNA.

1. SHANK3

SHANK3 is a gene that plays a crucial role in the development and functioning of synapses. Synapses are the connections between brain cells, and they are essential for communication between neurons.

Mutations in the SHANK3 gene have been linked to several neurodevelopmental disorders, including autism.

A study published in the journal Nature Genetics in 2010 found that mutations in the SHANK3 gene were present in approximately 1% of individuals with ASD.

The study also found that individuals with SHANK3 mutations tended to have more severe symptoms of autism, including intellectual disability and language deficits.

2. NRXN1

NRXN1 is a gene that encodes a protein called neurexin 1, which plays a critical role in synaptic function. Like SHANK3, mutations in the NRXN1 gene have been associated with autism and other neurodevelopmental disorders.

A study published in the journal Science in 2010 found that individuals with ASD were more likely to have mutations in the NRXN1 gene than individuals without ASD.

The study also found that the mutations were more common in individuals with more severe symptoms of autism.

3. CHD8

CHD8 is a gene that encodes a protein called chromodomain-helicase-DNA-binding protein 8, which is involved in chromatin remodeling. Chromatin remodeling is the process by which DNA is packaged and regulated in cells.

Mutations in the CHD8 gene have been linked to ASD, intellectual disability, and macrocephaly (an abnormally large head).

A study published in the journal Nature in 2014 found that CHD8 mutations were present in approximately 1% of individuals with ASD.

The study also found that individuals with CHD8 mutations tended to have high IQ scores and severe symptoms of autism, including social and communication impairments.

4. TSC1 and TSC2

TSC1 and TSC2 are genes that encode proteins called hamartin and tuberin, respectively. These proteins are involved in the regulation of cell growth and division.

Mutations in either the TSC1 or TSC2 gene can cause a genetic disorder called tuberous sclerosis, which is associated with an increased risk of ASD and other neurodevelopmental disorders.

A study published in the journal Annals of Neurology in 2010 found that approximately 50% of individuals with tuberous sclerosis also had a diagnosis of ASD.

The study also found that individuals with both tuberous sclerosis and ASD tended to have more severe symptoms of autism than individuals with ASD alone.

5. CNTNAP2

CNTNAP2 is a gene that encodes a protein called contactin-associated protein-like 2, which is involved in the development and function of neurons.

Mutations in the CNTNAP2 gene have been associated with an increased risk of ASD and other neurodevelopmental disorders, including language impairments.

A study published in the journal Translational Psychiatry in 2019 found that the CNTNAP2 gene was significantly overexpressed (meaning that it was producing more protein than normal) in individuals with ASD compared to individuals without ASD.

The study also found that the overexpression of the CNTNAP2 gene was associated with more severe symptoms of autism, including social and communication impairments.

6. FMR1

FMR1 is a gene that encodes a protein called fragile X mental retardation protein (FMRP). FMRP is involved in the regulation of protein synthesis at synapses and is essential for normal brain development and functioning.

Mutations in the FMR1 gene can cause fragile X syndrome, which is the most common inherited cause of intellectual disability and is associated with an increased risk of ASD.

A study published in the journal PLoS One in 2019 found that individuals with fragile X syndrome had a significantly increased risk of ASD compared to the general population.

The study also found that individuals with both fragile X syndrome and ASD tended to have more severe symptoms of autism than individuals with ASD alone.

7. MECP2

MECP2 is a gene that encodes a protein called methyl-CpG-binding protein 2, which is involved in the regulation of gene expression by binding to DNA.

Mutations in the MECP2 gene can cause Rett syndrome, a rare genetic disorder that is associated with an increased risk of ASD.

A study published in the journal PLoS One in 2011 found that individuals with Rett syndrome had a significantly increased risk of ASD compared to the general population.

The study also found that individuals with both Rett syndrome and ASD tended to have more severe symptoms of autism than individuals with ASD alone.

8. GABRB3

GABRB3 is a gene that encodes a subunit of the gamma-aminobutyric acid (GABA) receptor, which is involved in the regulation of neuronal activity. Mutations in the GABRB3 gene have been associated with an increased risk of ASD and epilepsy.

A study published in the journal Translational Psychiatry in 2018 found that the GABRB3 gene was significantly underexpressed (meaning that it was producing less protein than normal) in individuals with ASD compared to individuals without ASD.

The study also found that the underexpression of the GABRB3 gene was associated with more severe symptoms of autism, including social and communication impairments.

9. 15q11-q13 Duplications

15q11-q13 duplications are genetic variations in which a segment of DNA on chromosome 15 is duplicated. These duplications have been associated with an increased risk of ASD and intellectual disability.

A study published in the journal Human Molecular Genetics in 2018 found that individuals with 15q11-q13 duplications had a significantly increased risk of ASD compared to the general population.

The study also found that individuals with both 15q11-q13 duplications and ASD tended to have more severe symptoms of autism, including language impairments.

10. PTEN

PTEN is a gene that encodes a protein called phosphatase and tensin homolog, which is involved in the regulation of cell growth and division.

Mutations in the PTEN gene can cause a genetic disorder called PTEN hamartoma tumor syndrome, which is associated with an increased risk of ASD and other neurodevelopmental disorders.

A study published in the journal Child Psychiatry and Human Development in 2019 found that individuals with PTEN mutations had a significantly increased risk of ASD compared to the general population.

The study also found that individuals with both PTEN mutations and ASD tended to have more severe symptoms of autism, including social and communication impairments.

Conclusion

Autism spectrum disorder is a complex neurodevelopmental disorder that has both genetic and environmental causes. In recent years, researchers have identified several genes that are associated with an increased risk of developing autism.

Some of the most commonly found autism-associated genes in human DNA include SHANK3, NRXN1, CHD8, TSC1 and TSC2, CNTNAP2, FMR1, MECP2, GABRB3, 15q11-q13 duplications, and PTEN. Further research is needed to understand how these genes contribute to the development of autism and to develop more effective treatments for individuals with autism and their families.