
January 4, 2002
Genetics and Heredity
Question from Derby, New Hampshire, USA:
My almost eight year old son has had type 1 diabetes since the age of four, and my 11 year old daughter was recently (the past 3 months) diagnosed. How common is it for siblings to have type 1 diabetes with no family history of the disease?
Answer:
The chances of a second sibling developing type 1A (autoimmune) diabetes is about 1:20, irrespective of whether there is a family history of this kind of diabetes. The figure is a little higher if the father is the affected first degree relative, and a little lower if it is the mother.
In the great majority people with new onset type 1A diabetes, there is no family history. This to a large extent is because although genetic predisposition can be assessed, the influence of environmental triggers are as yet unknown.
DOB