The document discusses the genetics behind autism spectrum disorder (ASD). It notes that while the genetics are complex, research suggests both genetic and environmental factors play a role. Studies of twins have found concordance rates between 56-95% in identical twins, suggesting a strong genetic component. Chromosomal abnormalities like deletions, duplications, and inversions have also been linked to ASD. The document examines different genetic studies of autism in twins, siblings, and families that provide evidence for a genetic basis of ASD. It concludes that autism likely has both genetic and environmental causes.

1. Rajeshwari kannan
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2.  Autism is a neurodevelopmental
disorder characterized by impaired
social interaction, verbal and non-
verbal communication and
restricted and repetitive behavior.
AUTISM

3. SYMPTOMS OF
AUTISM:

4. GENETICS BEHIND IT
• The genetics of autism is complex and it is unclear
whether autism spectrum disorder (ASD) is explained
more by multigene interactions or by rare mutations with
major effects.
• It is seen that the effects are not just genetic in nature ,
rather have some environmental implications too.
• Thus treatment of autism is a complex diagnosis to make.

5. It has been seen that Deletion (1), duplication (2) and inversion (3) are all
chromosome abnormalities that have been implicated in autism and are
considered a cause of ASDs

6. REASONS BEHIND THE
GENETIC APPROACH
• Autism and twins
• Prodigies share genetic
mutation with people with
autism
• Paternal link
• Sibling studies

7. • One of the best ways of understanding what effect genes do
• The researchers found that 56 percent – 95 percent of the
effect is estimated to be genetic, according to a study of 258
twins suggests.
• Genetic influences on autism are estimated to be between
74-98 percent according to research by the Medical Research
Council in the UK.

8. A small scale study in 1977 was the first of its kind to
look into the heritability of autism. It involved 10 DZ
and 11 MZ pairs in which at least one twin in each
pair showed infantile autism. It found a concordance
of 36% in MZ twins compared to 0% for DZ twins.
Concordance of "cognitive abnormalities" was 82%
in MZ pairs and 10% for DZ pairs.
In 12 of the 17 pairs discordant for autism, a
biological hazard was believed to be associated with
the condition

9. A study of 99 autistic probands which found a 2.9% concordance
for autism in siblings, and between 12.4% and 20.4%
concordance for a "lesser variant" of autism.
A study of 31 siblings of autistic children, 32 siblings of children
with developmental delay, and 32 controls. It found that the
siblings of autistic children, as a group, "showed superior spatial
and verbal span, but a greater than expected number
performed poorly on the set-shifting, planning, and verbal
fluency tasks."

10. • Environmental
interactions
• Genomic imprinting
• Multigene interactions
• Single Genes

11. AUTISM AND ASDs are very intriguing diseases where the cause
has still not been finalised and thus research is still on.
The genetic side to this disease will surely if proven to be true
have an impact on the medical action taken.
By far whatever we have achieved just leads us to believe that
autism has a genetic as well an environmental cause, and when
all these factors act up, it leads to the disease as we know it.