March 29, 2002
Genetics and Heredity
Question from Rock Hill, South Carolina, USA:
I do not have diabetes in my family and my children's father does not have it, but their paternal grandfather does, and he is one of 10 children, eight of who also have diabetes, and both of the great grandparents on the fathers' side had diabetes and died from complications.Their father is one of six children, none of who have developed diabetes yet. Neither my eight year old nor 11 year old sons are overweight, but my eight year old he is quite moody and stays thirsty. I was told and under the impression that when diabetes was primarily carried by the female it would be passed on to the children and so on. Is this true? Could this be why none of the six children have gotten it? Since it is not in my family but seemingly runs wild in their father's how often should I have them checked? Should I be worried?
I have to suppose that your sons’ paternal great grand parents both had a form of type 2 diabetes that made them susceptible to being overweight and to not taking sufficient exercise. They then passed these characteristics on to eight out of 10 in the next generation. In one of these affected offspring, the paternal grandfather, they were modified by the introduction of a less susceptible female line so that the following two generations have so far been free of diabetes.
In these circumstances and with no affected first or second degree relatives, I don’t think that it is necessary to measure fasting blood sugar levels in your sons, unless they were to show much more definite evidence of diabetes. It would still make sense though to be sparing of high calorie foods and to encourage physical exercise.
It would be of great interest to get a much more exact determination of the genetic component for the earlier diabetes, and it is becoming increasingly possible to do this. The procedure is expensive however, and, since for the most part, it doesn’t yet affect treatment, it is seldom pursued outside of a research project.