The samples were received in ethylenediaminetetraacetate (EDTA) tubes. According to the manufacturer’s instructions, DNA was extracted using the GeneJET Whole Blood Genomic DNA Purification Mini Kit (Thermofisher, Paisley, United Kingdom). The purified DNA was assessed for quality and quantity using NanoDrop 200 spectrophotometer (Thermofisher, Paisley, United Kingdom). Using standard polymerase chain reaction (PCR) techniques, a primer was used to capture the single nucleotide variant corresponding to the UCP2−866 G/A polymorphism (rs659366). In brief, 50 ng of DNA template was mixed with 0.5 µM of each of forward (5’ CAC GCT GCT TCT GCC AGG AC 3’) and reverse (5’ AGG CGT CAG GAG ATG GAC CG 3’) primers in a volume of 12.5 µL of sterile water. To make a total volume of 25 L, the mixture was mixed with an equal volume (12.5 µL) of the 2X PCR master mix (Phusion Green Host Start II High-Fidelity PCR Master Mix) (Thermo Fisher Scientific, Paisley, UK). The following thermal profile was used for the PCR amplification: Initial denaturation at 95°C for 4 minutes, then 35 cycles of denaturation at 94°C for 30 seconds, annealing at 58°C for 30 seconds, and elongation at 72°C for 30 seconds, followed by a 10-minute final extension step at 72°C. PCR products were digested by Mlu I restriction enzyme (NEB, Ipswich, MA, USA) and separated on 2% agarose gel electrophoresis. Due to the lack of a Mlu I site, the (−866)A/A genotype was identified by a single 363 bp fragment, whereas the wild-type (−866)G/G genotype was digested into 295 bp and 68 bp fragments.12 (link),14 (link)