Which type of diabetes is most likely in a 19-year-old man with family history of diabetes and symptoms of frequent urination and thirst?

The most appropriate type of diabetes for a 19-year-old man with a family history of diabetes, along with symptoms such as frequent urination and excessive thirst, is maturity onset diabetes of the young, often referred to as MODY. This form of diabetes is characterized by an early onset, usually before the age of 25, and has a significant genetic component. Given the young age of the individual and the family history, MODY is particularly relevant as it is typically inherited in an autosomal dominant manner.

MODY often presents with hyperglycemia and can mimic type 1 or type 2 diabetes but is distinct due to the specific genetic mutations responsible for its development. Other types of diabetes listed may not align with the patient's age and symptomatology. For instance, diabetes mellitus type 2 is usually associated with older age, obesity, and is influenced by lifestyle factors, making it somewhat less likely in a 19-year-old without those typical risk factors.

Diabetic ketoacidosis is an acute and serious complication of diabetes, most often associated with uncontrolled type 1 diabetes, not a type of diabetes in its own right. While LADA occurs in adults and shares characteristics of both type 1 and type 2 diabetes, it