
February 28, 2012
Genetics and Heredity
Question from Townsend, Montana, USA:
What are the odds of having three kids in the same family with type 1? Are there known environmental triggers (causes)?
Answer:
There are some families where there is clearly a much stronger genetic component and some families where some unknown environmental trigger seems to be involved. The genetic implications are somewhat stronger, however. For the second child in the same family, i.e., brother or sister, the risk is about 2 to 5%. For a third child, the risk is closer to 1/2 to 1% probably. All this is somewhat of an accident of which genes are passed along from the parents to the child and, of course, whether or not they are identical or not to the susceptibility genes with the person with diabetes in the first place.
SB