Signs and symptoms of diabetes, including maturity-onset diabetes of the young (MODY), include:

• Excessive thirst (polydipsia)
• Frequent urination (polyuria)
• Fatigue
• Unexplained weight loss
• Frequent infections, including persistent vaginal infections in women, skin infections and gingivitis (gum disease)

The severity of the diabetes symptoms associated with MODY varies depending on the variation that is diagnosed. MODY2 appears to be the mildest form of the disease, often causing only mild hyperglycemia and impaired glucose tolerance. MODY1 and MODY3 may require treatment with insulin.