combined data from various studies and calculated an overall sibling risk
The risk was 2.2% compared to 0.11% for someone with no siblings with ASD
20 times greater
Bailey et al
studied data from British twin study,focusing on twins where one had ASD
In MZ twins,60% both had autism,concordance rate for DZ twins was 0%
When looking at a broader definition,concordance rate was 92% for MZ twins and 10% for DZ twins
Ronald et al
looked at TEDS examining 3000 sets of twins
Social characteristics are influenced by genetics,81-86% variation being attributed to genetic factors
Bernier et al
some families only have 1 member with ASD(simplex) others have multiple members with ASD or traits that have not be diagnosed(multiplex)
In multiplex families ASD is likely inherited but in simplex families the cause is classed as 'de novo'.Meaning its a new mutation that happened during fertilisation.The mutation affects multiple genes
Sebat et al
10% of ASD cases are caused by de novo CNVS
de novo CNVS occur when parents are older,age is a risk factor for simplex ASD
Non-syndromic ASD is where its the main or only diagnosis without a clear cause
Syndromic ASD is when it accompanies another primary condition with a know single gene gentic cause
Example of syndromic is fragile X syndrome(FXS),a mutation in the FMR1 gene
