Rajeshwari kannan 15bcb0115

Autism and it’s genetic implications

Autism is a neurodevelopmental disorder characterized by impaired social interaction, verbal and non-verbal communication and restricted and repetitive behavior.

AUTISM

SYMPTOMS OF AUTISM:

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.

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

REASONS BEHIND THE GENETIC APPROACH

• Autism and twins• Prodigies share genetic

mutation with people with autism

• Paternal link• Sibling studies

AUTISM AND TWINS• 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.

CASE STUDIES ON THE TWIN ANGLE

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

SIBLING STUDIESA 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."

VARIOUS MODELS PROPOSED:

• Environmental interactions

• Genomic imprinting• Multigene interactions• Single Genes

CONCLUSION: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.