A variant TATA box in the bilirubin UDP-glucuronosyltransferase 1 gene promoter does not contribute to neonatal jaundice in the Japanese population

UGT1A1 gene mutations and neonatal hyperbilirubinemia in Guangxi Heiyi Zhuang and Han populations

BACKGROUND

Uridine diphosphoglucuronate-glucuronosyltransferase 1A1 (UGT1A1) gene mutation was shown to be responsible for neonatal hyperbilirubinemia. This study aimed to investigate whether UGT1A1 gene mutation is associated with neonatal hyperbilirubinemia in Guangxi Heiyi Zhuang and Han populations.

METHODS

Two hundred and eighteen infants with hyperbilirubinemia (118 Heiyi Zhuang, 100 Han) and 190 control subjects (110 Heiyi Zhuang, 80 Han) were enrolled. Polymerase chain reaction and gene sequencing were used to detect the TATA-box and exon 1 of UGT1A1.

RESULTS

(TA)7 insertion mutation, 211G>A (G71R), 686C>A (P229Q), and 189C>T (D63D) were detected. Logistic regression analysis showed odds ratios (OR) of 2.64 (95% confidence interval (CI) 1.64-4.24; P < 0.001) and 0.69 (95%CI 0.43-1.10; P = 0.115) for neonates who carried UGT1A1 G71R and (TA)7 insertion mutation, respectively. G71R homozygosity increased the odds of dangerous bilirubin levels by a factor 34.23, and G71R heterozygosity only by 2.10.

CONCLUSION

We found that UGT1A1 G71R mutation is a risk factor for neonatal hyperbilirubinemia in Guangxi Heiyi Zhuang and Han populations. Meanwhile, the UGT1A1 (TA)7 insertion mutation is not associated with neonatal hyperbilirubinemia in the two ethnic groups.

Frequencies of A(TA)7TAA, G71R, and G493R mutations of the UGT1A1 gene in the Malaysian population

BACKGROUND

Gilbert syndrome is caused by defects in the uridine diphosphate glucuronosyltransferase 1A1 (UGT1A1) gene. These mutations differ among different populations and many of them have been found to be genetic risk factors for the development of neonatal jaundice.

OBJECTIVES

The objective was to determine the frequencies of the following mutations in the UGT1A1 gene: A(TA)7TAA (the most common cause of Gilbert syndrome in Caucasians), G71R (more common in the Japanese and Taiwanese population), and G493R (described in a homozygous Malay woman with Crigler-Najjar syndrome type 2) in a group of Malaysian babies with hyperbilirubinemia and a group of normal controls.

METHODS

The GeneScan fragment analysis was used to detect the A(TA)7TAA variant. Mutation screening of both G71R and G493R was performed using denaturing high performance liquid chromatography.

RESULTS

Fourteen out of fifty-five neonates with hyperbilirubinemia (25%) carried the A(TA)7TAA mutation (10 heterozygous, 4 homozygous). Seven out of fifty controls (14%) carried this mutation (6 heterozygous, 1 homozygous). The allelic frequencies for hyperbilirubinemia and control patients were 16 and 8%, respectively (p=0.20). Heterozygosity for the G71R mutation was almost equal among both groups (5.5% for hyperbilirubinemia patients and 6.0% for controls; p=0.61). One subject (1.8%) in the hyperbilirubinemia group and none of the controls were heterozygous for the G493R mutation (p=0.476).

CONCLUSIONS

The A(TA)7TAA seems more common than the G71R and G493R mutations in the Malaysian population.

Screening for G71R mutation of the UGT1A1 gene in the Javanese-Indonesian and Malay-Malaysian populations

BACKGROUND

There are significant differences in the prevalence and severity of neonatal jaundice among various populations. Recently, it has been reported that a mutation of the UGT1A1 gene, glycine to arginine at codon 71 (G71R), is related to the development of neonatal jaundice in East Asian populations. However, whether the G71R mutation contributes to the high incidence of neonatal jaundice in different Asian populations remains unknown. The authors screened for this mutation in the Javanese-Indonesian and Malay-Malaysian populations.

METHODS

One hundred and thirty-six subjects were enrolled in this study: 68 Javanese-Indonesian adults and 68 Malay-Malaysian newborns (32 with jaundice and 36 without jaundice). Denaturing high-performance liquid chromatography (DHPLC) was used to screen for the G71R mutation, and the results were confirmed by nucleotide sequencing analysis.

RESULTS

With DHPLC, the authors easily and clearly detected seven subjects carrying the G71R mutation: two Javanese-Indonesian adults and five Malay-Malaysian newborns. In the 68 Javanese-Indonesian adults, the genotype distribution for G71R mutation was 66 G/G, two G/R and no R/R genotypes, and the mutated allele frequency was 0.015. In the 68 Malay-Malaysian newborns, genotype distribution for the mutation was 63 G/G, five G/R and no R/R genotypes, and the mutated allele frequency was 0.037. The genotype distributions did not differ significantly between the newborns with jaundice and those without jaundice.

CONCLUSION

The G71R mutation is present, but very rare, in Javanese-Indonesians and Malay-Malaysians. Thus, G71R mutation may not contribute to the high incidence of the neonatal jaundice in South-east Asian populations. DHPLC analysis is a very useful method for detecting the G71R mutation.