Prevalence of prothrombin gene mutation (G-A 20210 A) in general population: a pilot study

The objective of this study was to determine the prevalence of prothrombin gene mutation in a sample population from Pakistan. Two hundred apparently healthy unrelated adults (older than 18 years) were included in the study. The sample population comprised 100 Punjabis (male 50, female 50) and 100 Pathans (male 50, female 50). Patients with a history of previous thromboembolism were excluded from the study. Five milliliters (5 mL) of whole blood was drawn in an EDTA bottle. The DNA was extracted by the standard phenol-chloroform method. The DNA was amplified between exon number 14 and the 3'-untranslated region of the prothrombin gene by a polymerase chain reaction in a thermal cycler. Amplified products were digested overnight with HindIII at 37 degrees C. The digested products were electrophoresed on 6% polyacrylamide gel. The fragments were visualized by silver nitrate staining. A heterozygous wild type and an uncut amplified product were included in the electrophoresis strip for quality control. The wild type of DNA ran as a 350-bp fragment and internal control was cut as 550- and 150-bp fragments. The abnormal prothrombin gene was cut into 350-, 322-, and 28-bp fragments. Only two cases of heterozygous prothrombin gene mutation G-A 20210A were found in the sample studied, giving an overall carrier rate of 01% (95% CI 0.4-2.4%) in the target population. Prothrombin gene mutation is present in our population but at a lower frequency than in the white population.