December 11, 2001
Genetics and Heredity
Question from Gainesville, Virginia, USA:
My 11 year old daughter was diagnosed with type 1 diabetes about a month and a half ago, her first cousin (my sister’s son) has cystic fibrosis, and the CF doctor suggested that I have my daughter tested for the CF gene. At diagnosis, she presented with all the typical signs (frequent urination, thirst, and weight loss). I have not been tested so I don’t know if I’m a carrier. The doctor said that there may be some link between a CF gene carrier and type 1 diabetes. Do you know of any information about this?
Children with cystic fibrosis have a significantly higher risk of diabetes than the general population. There is moreover good evidence that in some of these cases the diabetes has an autoimmune rather than a structural basis and that there is an increased prevalence of high risk HLA genes for autoimmune diabetes in these cases. However, I can find no report of a child with type 1A (autoimmune) diabetes developing cystic fibrosis nor of there being any genetic bias for this. Given this, I do not think that testing your daughter for the CF gene would have any merit.