Association of the cocaine and amphetamine-regulated transcript gene with type 2 diabetes mellitus

OBJECTIVE: To investigate whether genetic variation in cocaine and amphetamine-regulated transcript (CART) gene might contribute to the genesis of type 2 diabetes. METHODS: Screening for mutations in the entire coding region for the CART gene were performed with polymerase chain reaction-single strand conformation polymorphism (PCR-SSCP) in 180 normoglycemic control subjects and 221 patients with type 2 diabetes. RESULTS: (1) Adenine deletion was identified at position 1,457 nucleotide located at untranslation area of exon 3. In normal weight control, the frequencies of CART-A + and CART-A-alleles were 83.6% and 16.4% respectively. The frequencies of CART-A + A +, A + A-, A-A- genotype were 68.9%, 29.4% and 1.7% respectively. (2) In diabetic patients, the frequencies of CART-A + and A-alleles were 84.6% and 15.4% respectively; the frequencies of CART-A + A +, A + A-, A-A- genotype were 71.9%, 25.3% and 2.7% respectively. The frequency of A deletion of the CART gene in diabetic patients did not differ significantly from normoglycemic control subjects. (3) Diabetic patients with the A deletion had increased total cholesterol, low-density lipoprotein cholesterol and high-density lipoprotein cholesterol. CONCLUSION: Polymorphism was found in the 3'-untranslated region (Delta A1457) of CART in Chinese. A deletion in CART is not associated with type 2 diabetes, but may contribute to dyslipidemia.