What genetic mutations cause autism?

Inherited mutations in a gene called ACTL6B lead to autism, epilepsy and intellectual disability, according to a new study1. The mutations are recessive, which means that they lead to autism only if a person inherits them in both copies of the gene — one from each parent, who are silent carriers.

What is the most common known genetic cause of autism disorder?

Fragile X syndrome is the most common identified cause of inherited intellectual disability and the most common known cause of autism or autism spectrum disorders.

What is the second most common genetic cause of intellectual disability?

Many intellectual disabilities (ID, formerly mental retardation) are caused by genetic abnormalities. The two most common genetic causes of intellectual disabilities are Down syndrome and Fragile X syndrome.

What is syndromic ASD?

The traditional definition of syndromic ASD is a disorder with a clinically defined pattern of somatic abnormalities and a neurobehavioral phenotype that may include ASD. Most have a known genetic cause. Examples include fragile X syndrome and tuberous sclerosis complex.

Is autism genetic or hereditary?

Autism is estimated to be 40–80% heritable. However, both genetic and non-genetic factors modulate the penetrance of risk genes, resulting in a highly heterogeneous disease phenotype for similar pathogenic variants.

What is syndromic and non syndromic autism?

Syndromic autisms are caused by mutations in single genes and are manifested within the context of neurological syndromes, such as Fragile X Syndrome. In the last decade, genetic analyses of non-syndromic autism families revealed a number of genes that are linked to this class of autism.

What percent of ASD cases are syndromic?

We propose to differentiate syndromic ASD that occurs in the context of a “phenotype first” clinically defined syndrome, as described above and accounting for 4% to 5% of ASD cases,8,9 from that which is molecularly defined (“genotype first”) (Figure 1).