Endocrine Abstracts

Background and aim: The TaqI (rs1800497) polymorphism of the Dopamine Receptor type 2 (DRD2) gene allele has been commonly related to increased ad lib food intake, weight gain, and risk for obesity overeating and risk for obesity. We supposed to find associations between body mass index (BMI), the TaqI (rs1800497) polymorphism of the Dopamine Receptor type 2 (DRD2) gene and plasma leptin and dopamine in children with alimentary and extreme obesity and normal weight.

Materials and methods: Retrospective analysis in 288 children aged from 0,4 to 17,9 years were performed in children who appealed to endocrinologist for medical aid from 2009 to 2015 y. 179 children were randomly genotyped in the rs1800497 of DRD2 gene. Children were split up in terms of BMI into 3 groups: the 1st – normal weight (NW) (±1 S.D.S., n=30), the 2nd – alimentary obesity (AO) (≥+2 S.D.S. <+4 S.D.S., n=98), the 3rd – extreme obesity (EO) (≥+4 S.D.S., n=160). Plasma dopamine (D) and leptin (L) concentrations were detected by enzyme-linked immunosorbent assay (ELISA). According to percentiles of D levels children were divided to 4 groups: the 1st – patients with low D levels (<4.99 pg/ml); th 2nd – decreased D (4.99 – 11.64 pg/ml); 3rd – increased D (11.65 – 60.0 pg/ml); 4th – high D levels (>60.0 pg/ml). Analogically patients were split up depending on L concentrations: the 1st – low L (<13.15 ng/ml); the 2nd – decreased L (13.15 – 23.78 ng/ml); the 3rd – increased (23.79 – 40.18 ng/ml); the 4th – high L (>40.18 ng/ml). Statistical analysis were performed by means of SPSS 21.0 (χ²-criterion, likehood ratio) (P<0.05).

Result: Children with NW had 6.7% of high D levels, 40% - decreased D, in comparison with EO group who had 32% patients with high D concentrations and 28% - increased D (P=0.038). There were found out L levels differences: 86.7% children with NW had low L; 34.7% patients with AO L levels were increased; 31.5% children with EO had high L concentrations and only 17.7% had low L (P=0.0001). Children with AO and EO had raised A1 TaqI DRD2 allele frequencies: in 45.5% equally in contrast with NW patients (9.1%) (P=0.012). There were not any links between A1A1 genotype, plasma D and L concentrations.

Conclusions: A1A1 allelic variant of TaqI (rs1800497) DRD2 polymorphism were significantly associated to plasma leptin and dopamine concentrations and BMI (P=0.012, P=0.038, P=0.0001 respectively).