The purpose of this study is to describe and compare the different types of diabetes that exist in people from white European and south Asian origin in the UK (United Kingdom) who are diagnosed with diabetes before they turn 30 years old. By doing this we hope to identify cases of MODY (maturity onset diabetes of the young), which is a rare genetic cause of diabetes that is frequently misdiagnosed. Identifying MODY cases is important, as the treatment may differ to conventional treatment for type 1 or type 2 diabetes.

People who meet the recruitment criteria, will be invited to attend for a single fasted 2 hour visit at our research facility. During the visit we will record details of their diabetes history as well as their general health and undertake blood and urine tests. At the end of the visit their participation will be complete. We will contact them later to discuss results of specialist blood tests and whether or not they have MODY, if they have had genetic testing performed.

Inclusion Criteria:

• Diagnosed with diabetes on the basis of fasting glucose and/or oral glucose tolerance test and/or HbA1c as per WHO criteria.
• Diagnosed with diabetes between 6 months and 30 years of age.
• South Asian ancestry- defined as self-reported ancestry and at least 2 grandparents from the Indian Subcontinent (India, Pakistan, Bangladesh or Sri Lanka).
• European ancestry - defined as self-reported ancestry and at least 2 grandparents from within Europe.

Exclusion Criteria:

• An established secondary cause of diabetes exists (for example recurrent pancreatitis, pancreatectomy, new onset diabetes after transplantation, Cushing's syndrome, acromegaly, steroid induced).
• Enrolled in another study.
• Have active malignancy or under investigation for malignancy.

People in the UK diagnosed with any type of diabetes before the age of 30 years from either white European or South Asian origin.