We performed DNA analysis using cord blood samples on 86 male Malay neonates diagnosed as G6PD deficiency in the National University of Malaysia Hospital by a combination of rapid PCR-based techniques, single-stranded conformation polymorphism analysis (SSCP) and DNA sequencing. We found 37.2% were 871G>A (G6PD Viangchan), 26.7% were nt 563 C>T (G6PD Mediterranean) and 15.1% were 487G>A (G6PD Mahidol) followed by 4.7% 1376G>T (G6PD Canton), 3.5% 383T>C (G6PD Vanua Lava), 3.5% 592C>T (G6PD Coimbra), 2.3% 1388G>A (G6PD Kaiping), 2.3% 1360C>T (G6PD Union), 2.3% 1003G>A (G6PD Chatham), 1.2% 131C>G (G6PD Orissa) and 1.2% 1361G>A (G6PD Andalus). Seventy-one (82.6%) of the 86 G6PD-deficient neonates had neonatal jaundice. Fifty seven (80%) of the 71 neonates with jaundice required phototherapy with only one neonate progressing to severe hyperbilirubinemia (serum bilirubin >340 micromol/l) requiring exchange transfusion. There was no significant difference in the incidence of neonatal jaundice, mean serum bilirubin level, mean age for peak serum bilirubin, percentage of babies requiring phototherapy and mean number of days of phototherapy between the three common variants. In conclusion, the molecular defects of Malay G6PD deficiency is heterogeneous and G6PD Viangchan, Mahidol and Mediterranean account for at least 80% of the cases. Our findings support the observation that G6PD Viangchan and Mahidol are common Southeast Asian variants. Their presence in the Malays suggests a common ancestral origin with the Cambodians, Laotians and Thais. Our findings together with other preliminary data on the presence of the Mediterranean variant in this region provide evidence of strong Arab influence in the Malay Archipelago.

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The UGT1A1 Taqman MGB probe single nucleotide polymorphism (SNP) genotyping assay was developed to detect nucleotide 211 of the UDP-glucoronocyltransferase 1A1 (UGT1A1) gene. Defects in this enzyme interfere with process of conjugation of bilirubin and cause unconjugated hyperbilirubinemia. Variation at nucleotide 211 in the coding region of the UGT1A1 gene has been shown to be prevalent in Japanese and Chinese. Using an ABI sequence detection system (SDS) 7000, an allele-specific real-time PCR-based genotyping method was established to detect nucleotide G211A. Cord blood from 125 infants without hyperbilirubinemia (controls) were compared with cord blood from 74 infants (cases) with severe hyperbilirubinemia (total serum bilirubin > 300 micromol/L). Homozygous variation of the UGT1A1 gene at nucleotide 211(A/A) is significantly more common in cases (14.9%) than in controls (0.8%) (P<0.001). Direct sequencing from 20 randomly selected samples showed eight samples with homozygous wild type, seven with homozygous variant, and five samples were heterozygous. The result from this assay was in complete concordance with the DNA sequencing result and clearly discriminate wild-type (G/G), homozygous variant (A/A), and heterozygous (G/A). This assay is rapid and robust for screening of SNP G211A to determine if this polymorphism plays a role in causing severe neonatal jaundice in the local context.

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