Analysis showed that BMI (OR: 1.03; 95% CI: 0.92–1.12; p = 0.03), TG levels (OR: 2.4; 95% CI: 1.82–3.29; p < 0.001), LDL-C levels (OR: 1.76; 95% CI: 1.42–2.18; p < 0.001), family history of CAD (OR: 1.85; 95% CI: 1.01–3.89; p = 0.01), hypertension (OR: 3.26; 95% CI: 1.52–6.98; p < 0.001), obesity (OR: 1.53; 95% CI: 1.19–2.01; p = 0.02), smoking (OR: 1.8; 95% CI: 1.2–3.89; p < 0.001), insulin (OR: 4.71; 95% CI: 2.3–9.65; p < 0.001), and hyperlipidemia (OR: 2.56; 95% CI: 1.12–4.06; p < 0.001) are important risk factors of CAD severity in type 2 diabetic patients. The gene discussed is INS; the disease is obesity due to melanocortin 4 receptor deficiency.