A 29 years old person is known diabetic on oral hypoglycemic agents since 3 years. He has lost weight and never had DKA. His grand father is diabetic but his father is non diabetic. Which of the following is the likely diagnosis?

Since the patient in the question has a positive family history of diabetes, never had DKA and his diabetes being managed by oral hypoglycemic agents (non insulin dependence) suggests a possible diagnosis of Type II DM or MODY. Although weight loss and young age of presentation is more consistent with MODY, absence of Diabetes in his father makes MODY an unlikely diagnosis as MODY is inherited in an autosomal dominant manner and veical transmission through at least two generations is required for its diagnosis. So he is most likely suffering from Type II DM. Ref: Harrison's Internal Medicine, 18th Edition, Chapter 344; Current Medical Diagnosis and Treatment, 2012, Chapter 27