
October 24, 2003
Genetics and Heredity
Question from Sayville, New York, USA:
My 37 year old husband has had type 1 diabetes for about 13 years, we now have two beautiful daughters (ages three and six), and I recently “heard” a statistic that fathers are more likely to “pass” the likelihood of developing type 1 diabetes to their daughters in greater numbers than to any sons they may have. I’m curious as to the validity of that statement. Are there any tests my daughters can have done that may indicate a predisposition to developing type 1 diabetes in the future? My girls don’t present with any symptoms, but both do have their fair share of health issues that their dad has as well.
Answer:
In North America and Western Europe, an overall risk figure for developing type�1 diabetes before the age of 18, where one parent is affected, has been given as around 5% with the incidence 1% or so higher when the father is the proband and 1% lower when it is the mother. These percentages were established before it was understood that not all people with type 1 diabetes had an autoimmune basis and long before the entity of Latent Autoimmune Diabetes in Adults (LADA) was defined. Nowadays, the definitions of type 1 diabetes that presents in the older age group have been further expanded as to whether the onset is prolonged or relatively sudden and as to what types of antibodies they have. In other words, the 5% figure is still a reasonable but rather imprecise figure in any individual situation.
As to any tests, it is important to realise that at present there seems to be no way of averting insulin dependence once the autoimmune process starts, so that testing is more a matter of satisfying curiosity than of direct benefit to the children. You could talk to your daughters’ pediatrician about getting antibody tests done: negative tests at this time would not exclude the possibility of diabetes at a later date, but if positive, could distinguish between ‘very unlikely’ in the next five years and ‘quite probable’. A more expensive approach would be HLA antigen testing which would have he possibility of showing a protective gene and could also further define the risk. Obviously, I am rather for letting well alone.
DOB