September 28, 2001
Genetics and Heredity
Question from a nurse in Cleveland, Ohio, USA:
I am an obstetrical nurse and the mother of a child with type 1 diabetes. This week, I took care of a newly-delivered mother, who claimed that her husband’s (he has type 1) doctor stated that their new baby couldn’t get diabetes, since it “skips generations.” She said that her husband has diabetes, as did his grandmother, his great-great-grandmother, etc. Does this make sense to you? It goes against everything I have learned about diabetes.
Answer:
If the father in this instance does indeed have type 1A (autoimmune diabetes then the overall chance of the new baby developing the same problem is about 6%. This kind of diabetes is attributable in part to a complex genetic component and in part to a so far ill-defined environmental factor. The latter factor can of course vary with geography, but the genetic influence cannot ‘skip a generation’ although the development of actual clinical diabetes will depend on the specific alleles inherited from mother and father. The relevance of the family history depends of course on what kind of diabetes it was: in all probability it was primarily type 2 which would have no bearing on type 1 in the baby.
DOB