Prevalence and molecular study of G6PD deficiency in Malaysian Orang Asli

This study aims to define the prevalence and the molecular basis of G6PD deficiency in the Negrito tribe of the Malaysian Orang Asli. Four hundred and eighty seven consenting Negrito volunteers were screened for G6PD deficiency through the use of a fluorescent spot test. DNA from deficient individuals underwent PCR-RFLP analysis using thirteen recognized G6PD mutations. In the instances when the mutation could not be identified by PCR-RFLP, the entire coding region of the G6PD gene was subjected to DNA sequencing. In total, 9% (44/486) of the sample were found to be G6PD-deficient. However, only 25 samples were subjected to PCR-RFLP and DNA sequencing. Of these, three were found to carry Viangchan, one Coimbra and 16, a combination of C1311T in exon 11 and IVS11 T93C. Mutation(s) for the five remaining samples are unknown. The mean G6PD enzyme activity ranged 5.7 IU/gHb in deficient individuals. Our results demonstrate that the frequency of G6PD deficiency is higher among the Negrito Orang Asli than other Malaysian races. The dual presence of C1311T and IVS11 T93C in 64% of the deficient individuals (16/44) could well be a result of genetic drift within this isolated group.