May 8, 2000
Genetics and Heredity
Question from Garland, Texas, USA:
My brother has Type 1 diabetics pretty bad. He takes about 4 shots daily. No one else in the family — on either side — has had diabetes, except for my mother’s mother who developed Type 2 when she was about 50-60 years old. She had 12 children and her body was pretty worn out. We have energetic people on both sides of our family who have done the family tree thing, going back several hundred years. We even have published our family history in a hardback book, just for our own interest. No one has had been a diabetic in all these years. Can just one member of the family have something like a spontaneous mutation which would cause that person to have Type 1 diabetes and/or could it happen just as a fluke of nature? Or, is a diabetic condition always be an inherited condition — even if it goes back many generations — caused by an inherited DNA defect?
You can find extensive information about the genetics of type 1 diabetes on this web site. In brief, the exact mode of inheritance is unknown and most people who develop type 1 diabetes have no family history. Your family history research, however, is impressive.