The goal of this observational study is to evaluate the predictive value of the genetic risk score for type 1 diabetes in the progression to insulin deficiency in diabetic patients. The main question it aims to answer is:

1. To investigate the predictive efficacy of the genetic risk score for T1DM in determining whether diabetic patients will progress to insulin deficiency;
2. To compare the differences in genetic characteristics between the insulin-deficient cohort and the non-insulin-deficient cohort.

This study is a nested case-control study, in which a case group and a control group are set up for the collection of observational indicators. Case group: Diabetic patients who "progressed to insulin deficiency" and those who "progressed to severe insulin deficiency". Control group: Patients who did not progress to insulin deficiency. The study period is 3 years.

Inclusion Criteria:

• Gender is not restricted.

• Age ranges from 14 to 50 years old.

• Diagnosis of diabetes within < 1 year:

  1. If there are diabetes symptoms and meet any of the following criteria:① Plasma glucose at any time ≥ 11.1 mmol/L (200 mg/dL), or② Fasting plasma glucose ≥ 7.0 mmol/L (126 mg/dL), or③ Plasma glucose 2 hours after OGTT/post - meal ≥ 11.1 mmol/L (200 mg/dL), or④ HbA1c ≥ 6.5%.
  2. If there are no diabetes symptoms, another test on a different day is required for diagnosis.

• Newly - diagnosed diabetes patients whose type diagnosis is considered unclear clinically.

Exclusion Criteria:

• Peak C-peptide < 200 pmol/L;
• Gestational diabetes, monogenic diabetes (neonatal diabetes, MODY), exocrine pancreatic diseases (cystic fibrosis), diabetes caused by drugs or chemicals;
• Those who have been under long-term treatment with hormones or immunosuppressants;
• Pregnant or lactating women;
• Those with concurrent malignant tumors or severe heart, liver, and kidney diseases;
• Those with an expected survival time of less than 3 years;
• Those with mental disorders or unable to cooperate with the investigation for other reasons;
• Acute phase of diabetic ketoacidosis;
• Stress conditions such as severe infection, fever, trauma, and major surgery;
• Patients lacking major clinical information;
• Those considered by the researcher as unfit to participate in this study.

This study will enroll newly-diagnosed diabetic patients whose clinical subtype is unclear. Participants must be aged between 14 and 50 years, with a diabetes diagnosis within the past year, confirmed by standard American Diabetes Association (ADA) criteria. A key pathophysiological criterion is a peak C-peptide level < 200 pmol/L, suggesting impaired insulin secretion.

Key Exclusion Criteria: Patients will be excluded for conditions that could confound the etiology of diabetes or pose additional risks, including:

Specific diabetes subtypes (e.g., gestational diabetes, monogenic diabetes, pancreatic diseases).

Comorbidities such as malignant tumors or severe organ dysfunction. Acute metabolic derangements (e.g., ketoacidosis). Conditions limiting life expectancy or ability to participate (e.g., expected survival < 3 years, psychiatric disorders).

Current pregnancy or lactation.