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。     

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.     

Relationship between exposure to icterogenic agents, glucose-6-phosphate dehydrogenase deficiency and neonatal jaundice in Nigeria

In a study of the relationship between exposure to icterogenic agents, G-6-PD deficiency and severe neonatal jaundice (NNJ) (serum bilirubin greater than or equal to 205 mumol/l) 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 less than 0.01). The proportion of infants exposed to icterogenic agents in the two groups was very similar (p greater than or equal to 0.5). There was a strong association between exposure to icterogenic agents and NNJ in 83 G6PD deficient infants (p less than 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 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.     

(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 hyperbilirubinemia associated with glucose-6-phosphate dehydrogenase deficiency in Sephardic-Jewish neonates: incidence, severity, and the effect of phototherapy.

Glucose-6-phosphate dehydrogenase (G-6-PD) deficiency is frequently associated with neonatal hyperbilirubinemia, and sometimes kernicterus, often in the absence of any identifiable trigger or hematological evidence of hemolysis. The aim of this study was to compare the incidence and severity of, and the effect of phototherapy on, jaundice in G 6-PD-deficient vs G-6-PD-normal neonates in the Sephardic-Jewish community. Healthy term newborns, born to mothers of families stemming from geographic areas known to be "at risk" for G-6-PD deficiency, were screened for the condition and surveyed for hyperbilirubinemia. Seventy-five G-6-PD-deficient neonates formed the study group, while 266 neonates with normal levels of the enzyme formed the control group. Neonates with any other identifiable cause for jaundice were excluded. Phototherapy was commenced when the serum bilirubin levels reached 16 mg/dL (274 mumol/L) or more, and it was discontinued at 12 mg/dL (205 mumol/L) or less. Hyperbilirubinemia developed in 27 (36%) of the deficient neonates (serum total bilirubin greater than 13.9 mg/dL [238 mumol/L]), compared with 50 (18.8%) of control neonates (P = .002), while 20 (26.7%) of the study group required phototherapy, compared with 31 (11.7%) of control neonates (P = .002). Two neonates in the study group required exchange transfusion (serum bilirubin greater than 20 mg/dL [342 mumol/L]), vs 0 in the control group (not significant).(ABSTRACT TRUNCATED AT 250 WORDS)     

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.     

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.     

Neonatal jaundice in very low birth weight babies

Very low birth weight (VLBW) neonates born between January 1995 to December 1998, who survived for >2 days, were studied for the incidence, causes and interventions required for neonatal jaundice. Significant neonatal jaundice was defined as the total serum bilirubin (TSB) level beyond which baby required intervention (phototherapy and/or exchange transfusion) for neonatal jaundice. The incidence of significant neonatal jaundice (NNJ) was 76.6% and 37.3% required exchange transfusion. It was 82.9% at gestational age ≤28 weeks reduced whereas to 56.9% at gestational age of 35—36 weeks. The incidence was 75.3%, 78.5% and 76.7% in the birth weight group of 750—799 grams, 1000—1249 grams and 1250—1499 grams respectively. Glucose 6 phosphatase dehydrogenase (G-6-PD) deficiency (12.1%) was the commonest cause of jaundice. There is a need for evaluation of prophylactic therapies that enhances liver function or decreases production of bilirubin, which would prevent the rise of TSB to dangerous levels and thus would decrease the need for exchange transfusions.     

广西南宁地区G6PD基因突变与新生儿黄疸的关系

目的：分析本地区最常见的三种基因突变型G1388A、G1376T和A95G与葡萄糖-6-磷酸脱氢酶（G-6-PD）活性之间的相关性,并探讨G-6-PD基因突变对新生儿黄疸的影响。方法：124例广西南宁的高胆红素血症新生儿为研究对象。应用突变特异性扩增系统法检测G-6-PD基因突变,应用硝基四氮唑蓝（NBT）定量法检测G-6-PD活性。比较G-6-PD不同基因突变型之间以及与正常组之间胆红素脑病发生率、出生72 h后血清胆红素峰值组间的差异。采用非条件logistic回归分析血清胆红素值>340 μmol/L的危险度。结果：124例中有37例G-6-PD 基因突变（G1388A 20例,G1376T 14例,A95G 4例,1例同时存在G1388A与A95G突变）。20例G1388A突变者中5例（25%）G-6-PD酶活性正常,14例G1376T突变者中4例（29%）G-6-PD酶活性正常,4例A95G突变者G-6-PD 酶活性均缺乏。G1388A与G1376T组胆红素脑病发生率及出生72 h后血清胆红素峰值差异无显著性。G-6-PD 突变组出生72 h后血清胆红素峰值、胆红素脑病发生率及血清胆红素>340 μmol/L的危险度与G-6-PD正常组相比,差异无显著性。结论：广西南宁地区G-6-PD突变仍常见G1388A、G1376T和A95G基因型。NBT法诊断G-6-PD缺乏存在假阴性。不同基因型对出生72 h后血清胆红素峰值、胆红素脑病发生率的影响无差异。单独的G-6-PD基因突变对生后72 h血清胆红素峰值、急性胆红素脑病发生率及血清胆红素大于340 μmol/L危险性均无影响。［中国当代儿科杂志,2009,11（12）：970-972］     

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.     

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.     

EFFECT OF OROTIC ACID UPON SERUM BILIRUBIN IN NEWBORN INFANTS WITH ERYTHROCYTE G-6-PD DEFICIENCY

Fifty mature male newborns with erythrocyte G-6-PD deficiency were used for a study con cerning the effectiveness of orotic acid in preventing severe hyperbilirubinemia. Twentyfive randomly selected neonates were given orotic acid (100 mg/kg/day) orally in two daily doses from their 1st to their 5th day of life. Twenty-five newborns were not treated According to these results orotic acid does not seem to be effective in preventing severe hyperbilirubinemia, which frequently occurs in newborn babies' with erythrocyte G-6-PD deficiency. and served as controls. Six exchange transfusions were performed in the test group and six in the controls.     

Increased incidence of hyperbilirubinaemia in 'unchallenged' glucose-6-phosphate dehydrogenase deficiency in term Saudi newborns.

The incidence of severe hyperbilirubinaemia was significantly higher among the G6PD-deficient Saudi infants born at term than in non-deficient babies (34% vs 9%) (p less than 0.005). No apparent offending factors were detected in either the babies or their mothers. All babies who developed hyperbilirubinaemia did so during the 1st week of life. The highest mean bilirubin level for all jaundiced G6PD-deficient babies was recorded on the 4th postnatal day. Although the incidence of severe hyperbilirubinaemia among our neonates was relatively high, only two of them (7%), a boy and a girl, required exchange transfusions. Five of 29 jaundiced babies with G6PD deficiency were readmitted after discharge because of significant jaundice. One required exchange transfusion. Since G6PD deficiency seems to be a relatively common cause of neonatal jaundice in Saudi newborns, early detection of this enzymopathy by cord blood screening is justified to avoid morbidity and deaths.     

Effect of vitamin K1 on glucose-6-phosphate dehydrogenase deficient neonatal erythrocytes in vitro

AIM: To determine whether vitamin K1, which is routinely administered to neonates, could act as an exogenous oxidising agent and be partly responsible for haemolysis in glucose-6-phosphat-dehydrogenase (G-6-PD). METHODS: G-6-PD deficient (n = 7) and control (n = 10) umbilical cord blood red blood cells were incubated in vitro with a vitamin K1 preparation (Konakion). Two concentrations of Vitamin K1 were used, both higher than that of expected serum concentrations, following routine injection of 1 mg vitamin K1. Concentrations of reduced glutathione (GSH) and methaemoglobin, indicators of oxidative red blood cell damage, were determined before and after incubation, and the mean percentage change from baseline calculated. RESULTS: Values (mean (SD)) for GSH, at baseline, and after incubation with vitamin K1 at concentrations of 44 and 444 microM, respectively, and percentage change from baseline (mean (SD)) were 1.97 + 0.31 mumol/g haemoglobin, 1.89 +/- 0.44 mumol/g (-4.3 +/- 13.1%), and 1.69 +/- 0.41 mumol/g (-14.5 +/- 9.3%) for the G-6-PD deficient red blood cells, and 2.27 +/- 0.31 mumol/g haemoglobin, 2.09 +/- 0.56 mumol/g (-7.2 +/- 23.2%), and 2.12 +/- 0.38 mumol/g (-6.0 + 14.1%) for the control cells. For methaemoglobin (percentage of total haemoglobin), the corresponding values were 2.01 +/- 0.53%, 1.93 +/- 0.37% (-0.6 +/- 17.4%) and 2.06 +/- 0.43% (5.7 +/- 14.2%) for the G-6-PD deficient red blood cells, and 1.56 +/- 0.74%, 1.70 +/- 0.78% (12.7 +/- 21.9%), and 1.78 +/- 0.71% (20.6 +/- 26.8%) for the control red blood cells. None of the corresponding percentage changes from baseline was significantly different when G-6-PD deficient and control red blood cells were compared. CONCLUSIONS: These findings suggest that G-6-PD deficient red blood cells are not at increased risk of oxidative damage from vitamin K1.     

Congenital malaria among inborn babies at a tertiary centre in Lagos, Nigeria

Congenital malaria is increasingly reported among babies born to mothers continually residing in endemic areas. Given the high morbidity and mortality associated with malaria it is pertinent to determine its current status among newborns in Lagos, Nigeria. The aim was to determine the incidence of congenital malaria in newborn babies delivered at the Lagos University Teaching Hospital and also to determine the frequency of parasitaemia in their mothers and placentae. A cross-sectional study of mothers attending the antenatal clinic of the Lagos University Teaching Hospital was done. The Sociodemographic and clinical characteristics of mothers were documented. Samples of maternal, placental, cord and neonatal blood were taken and stained with Giemsa and examined for malaria parasites. Neonatal samples were examined at birth, on days 3, 7, 14 and 28. One hundred mothers and their placentae, as well as 104 babies and their cord blood were studied. The incidence of congenital malaria was 16/104 (15.3%) and parasite counts ranged from 47 to 1019/mul. Plasmodium falciparum was the predominant species. There was a strong association between placental, maternal, cord and neonatal parasitaemia. All the babies with congenital malaria had infected mothers, placentae and cords (p < 0.0001). In conclusion congenital malaria is not uncommon in Lagos nowadays, and there are relatively high rates of maternal, placental and cord blood parasitaemia. It is, therefore, recommended that babies born to mothers with malaria should be screened for congenital malaria.     

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.     

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.     

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.     

Effect of phenobarbital treatment on erythrocyte glucose-6-phosphate dehydrogenase in human newborns

The effect of phenobarbital (PB) treatment on erythrocyte glucose-6-phosphate dehydrogenase (G-6-PD) levels was studied in normal and G-6-PD-deficient human newborns. An increase of erythrocyte G-6-PD levels was observed in normal G-6-PD patients, while increase in the enzymatic activity was not observed in G-6-PD-deficient neonates.