I was wondering how diabetes is passed on. It is quite common in my friend’s family and he is very concerned!

I’ve heard that it is inherited, but can also arise because of obesity (type 2) or triggered by virus (type 1).

Do you know on which chromosomes/genes, this illness is situated on? And what signification inheritance has? Also, is it a typically Mendelian inheritance? If so is it a dominant/recessive gene? Is it possible to track through a pedigree?

What kind of other factors influence or trigger diabetes (type 1 and 2). For instance, fatness or obesity? Why do these influence and how much? What should my friend do? See a doctor, exercise, eat healthy (he is in physically good condition, and eats average food)?

There are many types of diabetes; but by far the commonest is type 2, which certainly runs in families; but as yet is not associated with a specific genetic locus. It is closely linked to obesity and an inactive lifestyle and a specific genetic locus is likely to be tied to one of the new hormonal factors that control appetite. If your friend knows that his family history relates to type 2 and is concerned about the possibility that he might get diabetes then he should discuss this with his doctor so as to get a clear idea of what his weight limitations might be and whether he has any further need to control his calorie intake.

type 1 diabetes or more particularly LADA (Late Autoimmune Diabetes in Adults) is a less likely possibility. Susceptibility is vested in a change in the HLA locus on the short arm of chromosome 6; but there is no simple dominant/recessive pattern to its occurrence because the development of actual clinical diabetes also depends on exposure to so far little understood environmental factors. Early exposure to cow’s milk was once thought to be an important and a number of viruses have thought to be responsible; but again the evidence is ambivalent.

DOB