By: Susan Aldridge, medical journalist, PhD
Diabetes is subject to genetic influences, as well as lifestyle factors like weight and exercise. In a new study, researchers at the Joslin Diabetes Center reveal that they have found a new gene linked to a form of diabetes that is of especial interest to researchers.
Maturity-onset diabetes of the young (MODY) is an unusual form of the disease that often occurs before the age of 25 and accounts for 2-3% of all diabetes cases. It is distinct from type 1 diabetes, which people are often born with, and type 2 diabetes that tends to develop in middle age. Type 1 and type 2 diabetes are subject to rather complex genetic influences in that several different genes appear to be involved and no single one can be said to cause the disease. MODY is caused by an autosomal dominant mutation, meaning that just one faulty gene inherited from either patient is sufficient to cause the disease. Such conditions are rare but are easy to diagnose – which is the case for this form of diabetes.
The new diabetes gene is called BLK and the study shows that it is involved in increasing insulin production. If defective, then insulin production becomes dysfunctional, which is a hallmark of all diabetes, not just MODY. Mutations in eight different genes have been found to cause MODY and account for 85% of cases. The cause of the remaining 15% cases remained obscure, even though it was known that autosomal dominant genes were involved, because of the family pattern of inheritance. In this study, six families with MODY were studied and five BLK mutations found. Now attention is focused upon the BLK pathway in diabetes. The findings might be used to develop a new genetic test for familial diabetes. It also advances our understanding of the disease and could provide a new target for drug therapy for diabetes of all kinds – for maybe insulin production can be stimulated in this way.
Doria A, Kulkami R et al Proceedings of the National Academy of Sciences early edition 10th August 2009
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