Relationship between Exposure to Icterogenic Agents, Glucose-6-Phosphate Dehydrogenase Deficiency and Neonatal Jaundice in Nigeria

ABSTRACT. In a study of the relationship between exposure to icterogenic agents, G-6-PD deficiency and severe neonatal jaundice (NNJ) (serum bilirubin 3±205 umol/I) in 234 Nigerian term male neonates, 106 infants with severe NNJ and 128 controls, it was found that 62.3 % of the jaundiced infants and 13.3 % of the infants without NNJ were G6PD deficient (p<0.01). The proportion of infants exposed to icterogenic agents in the two groups was very similar (p<0.5). There was a strong association between exposure to icterogenic agents and NNJ in 83 G6PD deficient infants (p<0.01), but there was no association between exposure to icterogenic agents and NNJ in the whole group of 234 infants or in 151 infants with normal G6PD status. It is concluded that there is an association between genetically determined G-6-PD deficiency and exogenous agents in causing severe NNJ in Nigerian infants.     

Neonatal jaundice and severity of glucose-6-phosphate dehydrogenase deficiency in Sardinian babies

We have investigated the association of neonatal jaundice (NNJ) and G6PD deficiency in consecutive births in a Northern Sardinian hospital. After excluding known causes for NNJ, and after correcting for the incidence of NNJ from unknown causes, we estimated that 20% of G6PD deficient male newborns develop NNJ resulting from their enzyme deficiency. By analyzing in detail 100 G6PD deficient babies we found no differences in birth weight or haemoglobin level between those without and those with NNJ, four of whom required exchange transfusion. We further showed by an accurate quantitative method that the residual G6PD enzyme activity was not significantly lower in G6PD deficient babies with NNJ compared to G6PD deficient babies without NNJ.     

Poor correlation between hemolysis and jaundice in glucose 6-phosphate dehydrogenase-deficient babies

BACKGROUND: The role of hemolysis in the pathophysiology of neonatal jaundice (NNJ) in patients with glucose 6-phosphate dehydrogenase (G6PD) deficiency has been questioned recently. The aim of the present study was to determine the contribution of hemolysis to the pathophysiology of jaundice in Malay neonates with G6PD deficiency and NNJ. METHODS: Four groups of babies were included in the study: (i) G6PD deficient with NNJ; (ii) G6PD deficient without NNJ; (iii) G6PD normal with NNJ; and (iv) normal controls. Babies with other known causes of jaundice were excluded from the study. All subjects underwent the following investigations on day 3-5 after birth: hemoglobin level (Hb), serum bilirubin level, carboxyhemoglobin (CO-Hb) concentration, reticulocyte count and full blood picture. The results of the investigations were compared between the groups using SPSS version 11. RESULTS: Babies with G6PD and jaundice had a similar percentage of CO-Hb to babies with G6PD without NNJ or babies with normal G6PD and NNJ (1.76 +/- 0.40% vs 1.66 +/- 0.31% and 1.67 +/- 0.28%, respectively; P: 0.23 and 0.41, respectively). Total Hb levels and reticulocyte counts were not significantly different between the groups. The blood film showed more (even though not reaching significance) hemolysis in the G6PD patients but results of the blood film were very similar for G6PD patients with and those without NNJ. CONCLUSION: Hemolysis is not a main determinant of neonatal jaundice in G6PD-deficient babies.     

广西恭城县瑶族和汉族居民G-6-PD缺乏症发病率及基因频率的调查

目的研究广西恭城县瑶族和汉族居民的G-6-PD缺乏症发病率及基因频率。方法使用G-6-PD试纸法初筛,四氮唑蓝定量法测定确认的方法调查对2050名(男1126,女1124)瑶族和874名(男481,女393)汉族初中学生进行G-6-PD缺乏症的调查。结果瑶族男缺乏率5·75%(显著缺乏4·87%,中度缺乏0·97%),瑶族女性缺乏率1.95%(显著0·59%,中度1·36%),瑶族男女合并总缺乏率为3·85%;瑶族男性基因频率为:0·057,瑶族女性杂合子的估计值为10·84%:汉族男性缺乏率7·06%(显著缺乏6·03%,中度缺乏1·04%),汉族女性缺乏率3·56%(显著0·76%,中度2·80%),汉族男女合并总缺乏率为5·49%;汉族男性基因频率为0·0706,汉族女性杂合子的估计值为13·12%;全县瑶族和汉族合并缺乏率为4·34%。结论恭城县G-6-PD缺乏发病率,瑶族比汉族的稍低,但民族间的差异比地域间的差异相对要小。     

Neonatal screening for glucose-6-phosphate dehydrogenase deficiency: sex distribution.

Eight hundred and six newborn infants at high risk for glucose-6-phosphate dehydrogenase (G-6-PD) deficiency were screened; 30.2% of the boys and 10.4% of the girls had severe G-6-PD deficiency. Surprisingly, 14% of the enzyme deficient girls had a father from a low risk ethnic group. Girls of high risk mothers should be screened for G-6-PD deficiency regardless of paternal origin.     

遗传因素在广西新生儿高胆红素血症中的作用

目的探讨UGT1A1 G71R突变、OATP2A388G突变和G-6-PD缺乏对在广西新生儿高胆红素血症发病的作用。方法用四氮唑蓝定量法（NBT法）测定G-6-PD酶活性。聚合酶链反应-等位基因特异性寡核苷酸探针点杂交（PCR-ASO）法确定G71R基因型。限制性片段长度多态性分析（RFLP）检测A388G基因型。测定109例新生儿脐血的G-6-PD活性及G71R基因型,其中101例同时检测了A388G基因型。据G-6-PD活性及G71R或A388G基因型分组,分析UGT1A1G71R突变、OATP2A388G突变和G-6-PD缺乏与足月新生儿高胆红素血症之间关系。结果G71R等位基因频率在G-6-PD缺乏组为22．03％,在G-6-PD正常组为28．00％。G-6-PD缺乏共存有G71R突变纯合子或杂合子的新生儿高胆红素血症发生率（95．50％）高于G-6-PD正常且G71R为野生型的新生儿（53．90％）,x^2=10．45,P=0．0012,前者发生高胆红素血症的机会比（95％可信区间）[OR（95％CI）]为18．00（2．12,152．9）。A388G等位基因频率在G-6-PD缺乏组为20．O％,在G-6-PD正常组为18．5％。G-6-PD缺乏共存有A388G突变新生儿的高胆红素血症发生率（90．0％）高于G-6-PD正常且A388G为野生型的新生）L（44．80％）,X2=10．39,P=0．0013,前者发生高胆红素血症的伽（95％CT）为11．08（2．15,56．48）。结论G71R突变与G-6-PD缺乏共存或A388G突变与G-6-PD缺乏共存对广西足月新生儿高胆红素血症的发生有协同作用。     

Efficacy of phototherapy in neonatal hyperbilirubinaemia associated with glucose-6-phosphate dehydrogenase deficient status

The efficacy of phototherapy in a group of 427 infants with hyperbilirubinaemia associated with glucose-6-phosphate dehydrogenase (G6PD) deficiency and a comparable group of 3924 G6PD normal infants with non-haemolhtic hyperbilirubinaemia was evaluated. Phototherapy was highly effective in reducing bilirubin levels in both groups of infants, being significantly more effective in the group with normal G6PD status. Failure rate was very low (2.03/1000) in the group with normal G6PD status and nil in the G6PD deficient group. Bilirubin rebound after phototherapy was unremarkable with very few infants requiring a second exposure —4.68/1000 in the G6PD deficient group and 6.37/1000 in the G6PD normal group. All the babies tolerated phototherapy well. Phototherapy would therefore seem to be a simple and effective method for the management of severe jaundice associated with G6PD deficiency.     

Cord blood G-6-PD activity by quantitative enzyme assay and fluorescent spot test in Chinese neonates

Glucose-6-phosphate dehydrogenase (G-6-PD) deficiency is a common X-linked recessive disorder among the Chinese population. Neonatal screening for this condition is important and with necessary precaution, enzyme deficient infants are less likely to develop severe haemolysis and subsequent kernicterus. Screening of G-6-PD deficiency by fluorescent spot test on cord blood samples of 1228 Chinese neonates revealed an incidence of 4.4% in males and 0.35% in females. Simultaneous direct enzyme assay confirmed the sensitivity and specificity of the spot test in the identification of male hemizygotes and female homozygotes. However, the spot test was unsatisfactory in detecting heterozygotes. Even quantitative enzyme assay could detect only 70% of the partially deficient subjects.     

Cord blood G-6-PD activity by quantitative enzyme assay and fluorescent spot test in Chinese neonates

Glucose-6-phosphate dehydrogenase (G-6-PD) deficiency is a common X-linked recessive disorder among the Chinese population. Neonatal screening for this condition is important and with necessary precaution, enzyme deficient infants are less likely to develop severe haemolysis and subsequent kernicterus. Screening of G-6-PD deficiency by fluorescent spot test on cord blood samples of 1228 Chinese neonates revealed an incidence of 4.4% in males and 0.35% in females. Simultaneous direct enzyme assay confirmed the sensitivity and specificity of the spot test in the identification of male hemizygotes and female homozygotes. However, the spot test was unsatisfactory in detecting heterozygotes. Even quantitative enzyme assay could detect only 70% of the partially deficient subjects.     

(TA)n UDP-glucuronosyltransferase 1A1 promoter polymorphism in Nigerian neonates

Nigerian neonates have a high incidence of bilirubin encephalopathy. Glucose-6-phosphate dehydrogenase (G-6-PD) deficiency is prevalent in this population. (TA)7 promoter polymorphism in the gene encoding the bilirubin conjugating enzyme UDP-glucuronosyltransferase 1A1 (UGT1A1) potentiates hyperbilirubinemia in G-6-PD deficient neonates. We studied (TA)n allele frequency to determine, at least in part, its contribution to the frequency and severity of hyperbilirubinemia. DNA was extracted from umbilical cord blood of sequentially born Nigerian neonates and the (TA)n UGT1A1 promoter sequence determined. The (TA)n allele distribution was compared with reported adults of varying African ancestry and Sephardic Jewish neonates. Among 88 Nigerian neonates, (TA)6 and (TA)7 alleles were almost equally distributed (0.46 and 0.43, respectively). Some individuals with (TA)5 and (TA)8 sequences were encountered. Allele distribution was similar to that of the African ancestry population but differed from the Sephardic Jewish newborns, in whom the (TA)6/(TA)7 distribution was 0.65/0.35. Whereas 45% of Nigerian alleles and 50% of African ancestry alleles, respectively, included a (TA)7 or (TA)8 sequence, only 35% of Jewish alleles were (TA)7 (p < 0.001), and no (TA)8 alleles were encountered. The high frequency of (TA)n promoter polymorphism, coupled with G-6-PD deficiency, may contribute to the pathogenesis of extreme neonatal hyperbilirubinemia in Nigeria.     

Neonatal screening for Glucose-6-Phosphate dehydrogenase deficiency

Objective : This study was carried out to detect the incidence of erythrocytic Glucose-6-Phosphate dehydrogenase (G-6-PD) deficiency, to compare the incidence of hyperbilirubinernia in G-6-PD deficient neonates as compared to G-6-PD normal neonates and to asses the usefulness of neonatal screening for G-6-PD deficiency.Method : In a retrospective hospital based study 2,479 male and female neonates consecutively born at Indraprastha Apollo hospital between July 1998 to June 2003 who were screened for G-6-PD levels were evaluated for the incidence of G-6-PD deficiency.Results : Incidence of G-6-PD deficiency was found to be 2.0%. Incidence in males was 283% and femle was 1.05%. The incidence of hyperbilirubinemia was found to be 32% in G-6-PD deficient neonates which was significantly higher than the incidence of hyperbilirubinemia in neonates with normal G-6-PD, which was 12.3% (P<0.001).Conclusion : Our data suggests that neonatal screening for G-6-PD deficiency is a useful test for preventing and early treatment of complications associated with it.     

Cord plasma alpha-fetoprotein values and neonatal jaundice

Umbilical cord plasma alpha-fetoprotein (AFP) values were determined in 127 infants with hyperbilirubinemia (56 glucose-6-phosphate dehydrogenase (G-6-PD) deficient and 71 G-6-PD normal) and 136 control subjects (73 G-6-PD deficient and 63 G-6-PD normal). The mean alpha-fetoprotein value of 173 +/- 35.2 (SD) mg/L for the group of infants with hyperbilirubinemia was significantly greater than that (122 +/- 21.7 mg/L) for the control infants (P less than .001). G-6-PD status and sex did not significantly affect the alpha-fetoprotein values. Using an alpha-fetoprotein level of 130 mg/L as a "cut-off" value, the incidence of false-positive results was 25.5% and the incidence of false-negative results was 11.8%. This test can be used as a screening procedure to detect infants at high risk for hyperbilirubinemia.     

Glucose-6-phosphate dehydrogenase deficiency and kernicterus of South-East anatolia

OBJECTIVE: We aimed to investigate the rate of kernicterus, and physical and laboratory examination findings in hyperbilirubinemic infants with glucose-6-phosphate dehydrogenase (G-6-PD) deficiency. MATERIALS AND METHODS: This study was carried out in the Dicle University Hospital Neonatal Intensive Care Unit between June 2005 and June 2006. Out of 56 male neonates who needed an exchange transfusion due to hyperbilirubinemia, 10 with G-6-PD deficiency were included in the study. Maternal age, gestational age, route of delivery, birth weight, age at the time of admission, and treatment and outcome were recorded. Laboratory investigations included determination of direct and indirect serum bilirubin concentrations, blood group typing, direct Coomb test, complete blood count, blood smear, thyroid-stimulating hormone, T4, C-reactive protein, urine analysis, and G-6-PD level. RESULTS: Out of 56 male neonates requiring exchange transfusion, 10 had G-6-PD deficiency (18%). In G-6-PD deficient neonates, other factors known to cause hyperbilirubinemia were excluded. The mean gestational age and the mean maternal age was 38.2+/-1.0 weeks and 31.3+/-5.9 years, respectively. The mean bilirubin level was 42.1+/-13.7 mg/dL. Four patients required a second exchange transfusions, and only 1 transfusion was sufficient for the remaining patients. Five patients (55%) developed kernicterus. CONCLUSIONS: Early detection of G-6-PD deficiency in the affected newborns may be important for reducing the risk of severe hyperbilirubinemia, kernicterus, and the need for exchange transfusion.     

G-6-PD缺陷与新生儿高胆、婴幼儿贫血及婴儿肝炎综合征关系的调查

广西是我国Ｇ－６－ＰＤ缺陷高发区。Ｇ－６－ＰＤ缺陷发病的主要表现为急慢性溶血性贫血和由此而产生的高间胆红素血症及胆汁郁积。近十年我院门诊及病房４４０例患儿：２３７例新生儿高间胆包括核黄症后遗症患儿。Ｇ－６－ＰＤ缺陷检出率达６９．６％，其中显著缺陷４３．９％（１０４／２３７），中间值２５．７％（６１／２３７）；１０３例３个月以下的婴儿贫血原因待查患儿，Ｇ－６－ＰＤ缺陷检出率达５９．２２％（３６／１０３）；１００例婴儿肝炎综合征患儿，Ｇ－６－ＰＤ缺陷检出率达１８％（１８／１００）。Ｇ－６－ＰＤ缺陷男女经例为２．３７：１。６７例进行家系调查，２８例Ｇ－６－ＰＤ缺陷男婴，母亲检出率为６７．８％（１８／２８）；１４例Ｇ－６－ＰＤ缺陷女婴，父亲检出率４３％（６／１４），母亲检出率５０％（７／１４）。说明了在我区Ｇ－６－ＰＤ缺陷是引起新生儿高间胆以及核黄痊后遗症、婴幼儿贫血较常见而且重要原因之一。     

Salicylamide glucuronide formation in newborn babies with G-6-PD deficiency

Salicylamide glucuronide formation has been studied in 23 newborn babies with erythrocyte G-6-PD deficiency and in 15 normal newborns on the first day of life. Glucuronide formation was significantly lower (p less than 0.001) in the former in comparison with the controls. In the newborns with G-6-PD deficiency who subsequently became hyperbilirubinemic an even lower mean glucuronide formation was observed (p less than 0.01) in respect to the non-jaundiced G-6-PD-deficient newborns.     

不同G-6-PD活性新生儿光疗致溶血机制及其预防

目的探讨不同G6PD活性新生儿光疗溶血机制及预防。方法将G6PD正常与缺陷光疗患儿随机分为维生素E干预组和对照组,测定比较超氧化物歧化酶(SOD)、丙二醛(MDA)、活性氧(ROS)、总胆红素(TB)、血红蛋白(Hb)及光疗指数。结果光疗前G6PD缺陷组比正常组SOD和Hb低,ROS高;光疗中G6PD缺陷干预组比正常干预组SOD高,MDA低,光疗指数小,G6PD缺陷对照组比正常对照组ROS、MDA高,光疗指数大(各组比较均P<0.01或P<0.05)。光疗后G6PD缺陷对照组Hb下降,并比干预组低,G6PD正常两组Hb均下降,干预组比对照组高(各组比较均P<0.01或P<0.05)。结论光疗可致抗氧化能力下降,脂质过氧化损伤致G6PD缺陷光疗者溶血更突出,维生素E干预更有效。     

Agar in control of hyperbilirubinemia of full-term newborn infants with erythrocyte G-6-PD deficiency.

40 full-term newborn infants with erythrocyte glucose-6-phosphate dehydrogenase (G-6-PD) deficiency were used for a study concerning the effectiveness of agar per os in preventing severe hyperbilirubinemia. 20 randomly selected neonates were given agar (1 g/kg/day) orally in 4 daily doses from their 1st to their 5th day of life. 20 infants were not treated and served as controls. Three exchange transfusions were performed in the experimental as well as in the control group. According to these results, agar does not seem to be effective in preventing severe hyperbilirubinemia, which frequently occurs in newborn infants with erythrocyte G-6-PD deficiency.     

Incidence and causes of sepsis in glucose-6-phosphate dehydrogenase-deficient newborn infants

To determine the susceptibility to sepsis in newborn infants deficient in glucose-6-phosphate dehydrogenase (G6PD), we screened 33,943 Saudi Arab infants. Deficiency of G6PD was found in 18%. Sepsis was determined by the presence of clinical signs of sepsis and confirmed by positive blood cultures. Sepsis was documented in 75 infants (2.2/1000). The incidence of sepsis was significantly higher in 6138 G6PD-deficient infants (3.4/1000) than in the 27,805 with normal G6PD activity (1.9/1000; p less than 0.02). The incidence of catalase-positive organism sepsis was higher in G6PD-deficient infants (2.9/1000) compared with those with normal G6PD activity (1/1000; p less than 0.0002), whereas the incidence of catalase-negative organism sepsis did not differ (p less than 0.2). Deficiency of G6PD was more common in infants with late sepsis (46%) than in those with early sepsis (21%) and in all infants screened (18%) (p less than 0.03 and p less than 0.001, respectively). We conclude that neonates with G6PD deficiency are more susceptible to late sepsis and to infection with catalase-positive organisms. The exact mechanism for the increased susceptibility is not clear, but a partial explanation could be lack of leukocyte bactericidal activity associated with G6PD deficiency, and an increased susceptibility to infection caused by hyperferremia resulting from lysis of G6PD-deficient erythrocytes.     

Genetic polymorphisms in Thai neonates with hyperbilirubinemia

Aim:  Polymorphisms of the UGT1A1 gene, SLCO1B1 gene and GST gene have been associated with significant hyperbilirubinemia. We would like to determine whether the variation of UGT1A1 gene, SLCO1B1 gene and GST gene may play a significant role in neonatal hyperbilirubinemia in Thai infants.
Methods:  Ninety-one study subjects (hyperbilirubinemic group) and 86 control subjects were studied.
Results:  The cause of neonatal hyperbilirubinemia could not be identified in 64 infants (70.3%), ABO blood group incompatibility in 14.3% and Glucose-6-phosphate dehydrogenase (G-6-PD) deficiency in 8.8%. In the hyperbilirubinemic group, 23 of 91 (25.3%) infants demonstrated variant of UGT1A1 at nucleotides (nt) 211 as compared to 6 of 86 (7%) in the control group (p = 0.001). There were no significant differences between groups in the variants UGT1A1 at nt 686, SLCO1B1 gene at nt 388, 463 and the GST gene. Male infants with G-6-PD deficiency were associated with hyperbilirubinemia (21.2% vs. 4.8% in the control group) with an odds ratio (OR) of 5.37 (p =0.02). The relationship between G-6-PD and variant in UGT1A1 gene at nt 211 could not be determined.
Conclusion:  Thai infants with variant in the UGT1A1 at nt 211 or with G-6-PD deficiency are at higher risk for developing neonatal hyperbilirubinemia.     

运用PCR-DGGE技术检测葡萄糖-6-磷酸脱氢酶缺乏的初步研究

目的：运用多聚酶链反应-变性梯度凝胶电泳（PCR-DGGE）技术检测葡萄糖-6-磷酸脱氢酶（G-6-PD）缺乏患者及基因携带者基因变异,探讨其对该病的诊断和研究价值。方法：提取G-6-PD缺乏症患者及其家系（患者父亲和/或母亲等）的外周血RNA,逆转录合成cDNA后,选取第11至12外显子部分cDNA片段进行PCR-DGGE,观察其电泳行为,将电泳行为异常的标本进行基因测序,最后做出基因诊断。结果:：36个家系中33个家系发现G-6-PD基因在1304至1520片段出现PCR-DGGE多种异常电泳区带。9例母亲G-6-PD/6-PGD比值低于1.00,其中3例比值低于0.50,而且PCR-DGGE电泳行为一致,基因测序发现为双重杂合子;比值正常的G-6-PD缺乏基因携带者母亲均为单杂合子。该片段基因测序发现3个突变位点分别为：C1311T,G1376T,G1388A。各基因突变的位点有其特殊的电泳行为。结论：PCR-DGGE技术是一种敏感性高、可靠性强的筛查基因突变的方法。在临床研究G-6-PD缺乏,特别是常规诊断技术不能发现的女性G-6-PD缺乏基因携带者的检测中具有很强的应用价值。［中国当代儿科杂志,2007,9（6）：529-532］