Bio Exp Genetic Prediposition

Question 1

Family study
Szatamari combined all the data from several studies to calculate the overall sibling risk
Thsi showed the proportion of siblings of people diagnosed with ASD, that also meet the criteria.
The rate was 2.2%
For someone without sibling the asd the rate was 0.11%
So 20x greater risk of developing ASD if you have a sibling with it

Answer 1

Shows there is some genetic explanation of developing ASD.
Seen through concordance rate of siblings

Question 2

Twin studies
Ritvo et al
Find concordance of 96% for MZ twins and 23% for DZ twins

Answer 2

Shows strong genetic component
With such high concordance rate for MZ twins

Question 3

What are simplex families

Answer 3

Families with just one member having ASD

Question 4

What are multiplex families

Answer 4

Families where more than one member has ASD or multiple people with autistic traits but not diagnosed

Question 5

How is ASD cause in simplex and multiplex families

Answer 5

Simplex- ASD is likely caused by De Novo mutation
Multiplex- ASD is likely to be caused by a genetic variation that is inherited

Question 6

What is the De Novo mutation

Answer 6

A genetic alteration that is present for the first time as a result of a variant in a germ cell of one of the parents, or a variant that arises in the fertilised egg itself during early embryogenesis.