LARGEST STUDY ON GENETIC RISK FOR TYPE 2 DIABETES

The diabetes field has long classified the disorder into genetically distinct groups, including type 1 and type 2. However, new genetics research focused on a form of type 2 diabetes (T2D) that is becoming more common in adolescents suggests a more complicated picture. Researchers at the Broad Institute of MIT and Harvard, Boston Children's Hospital, and Harvard Medical School analyzed DNA from more than 3,000 T2D participants between 12 and 18-years-old and nearly 9,800 adult controls, more than three-quarters of whom were of African American or Hispanic ancestry. They found that youth-onset T2D is a genetically intermediate form of the disorder that lies on a spectrum between adult-onset T2D and rare forms of the disorder caused by a single gene. Adult-onset T2D is influenced by thousands of common genetic variants, whereas the rare genetic forms, known as monogenic diabetes, are caused by a single variant. Moreover, these individuals harbored more of these variants than people 
with adult-onset T2D, suggesting that genetics has a larger role in causing youth-onset T2D than in the adult-onset form.The work also revealed that the specific mix of different types of variants a given individual carried correlated with their particular set of symptoms. For example, those with more common variants showed more symptoms of adult-onset T2D, such as high insulin levels. Disease-causing genetic variants are generally classified as common (appearing in more than 5 percent in the population), rare (less than 1 to 5 percent of population), or monogenic (which are able to cause disease on their own). Teasing apart the contributions of these different types of variants in youth-onset T2D risk requires genetic data from thousands of patients