The father of a boy with autism asks to speak to you privately at the end of a clinic. His wife has become pregnant and he is anxious about the risk of autism in his second child. Which of the following is the best approximation of the increased sibling risk of autism when compared to the general population?
Exam Question Feb 2008
Exam Question Feb 2008
Autism (genetics)
There is strong evidence for a genetic component to autism.
Siblings of autistic individuals are approximately 50 to 100 times more likely to develop autism than a person in the general population.
Twin studies of autism show an extraordinarily high heritability but also demonstrate the genetic complexity of these disorders, The most recent and largest study in this area (Frazier 2014) revealed a monozygotic concordance of around 76% with the DZ twin concordance of 34% (for same sex pairs and 18% for boy girl pairs) suggesting a highly multigenic mode of inheritance.
The molecular genetics is still poorly understood. Copy number variations (CNVs) are implicated along with a number of candidate genes.
Frazier (2014) A twin study of heritable and shared environmental contributions to autism. J Autism Dev Disord. Aug 44(8):2013-25
