My husband has type 1 diabetes and so do my two year old son and four year old daughter. How often to you hear of or see families in which a parent and both children have type 1 diabetes?

If your husband has type 1A (autoimmune) diabetes, then the chances of any of your offspring developing the same form of diabetes are about 1:20 in each case, but the chances of having two such affected children are only 1:400. This figure however is a simple overall value that does not take into consideration other factors that affect vulnerability to autoimmune problems such as HLA antigen genetic type and the influence of the still little understood environmental factors.

DOB
Additional comments from Dr. David Schwartz:

Unfortunately, I think the answer to your question is “too often.” One of the larger factors for increasing the risk of developing type 1 diabetes is that the father has it.

DS
Additional comments from Dr. Andrea Scaramuzza:

I know of at least four families in Italy in which there are two children and a father or mother all of whom have type 1 diabetes.

AS