ABCB4 p.Gly762Glu
| Predicted by SNAP2: | A: N (72%), C: D (66%), D: D (75%), E: D (85%), F: D (75%), H: D (80%), I: D (71%), K: D (91%), L: D (80%), M: D (71%), N: D (63%), P: D (85%), Q: D (80%), R: D (85%), S: D (53%), T: D (59%), V: D (75%), W: D (85%), Y: D (80%), |
| Predicted by PROVEAN: | A: D, C: D, D: D, E: D, F: D, H: D, I: D, K: D, L: D, M: D, N: D, P: D, Q: D, R: D, S: D, T: D, V: D, W: D, Y: D, |
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[hide] Sequence analysis of bile salt export pump (ABCB11... Pharmacogenetics. 2004 Feb;14(2):91-102. Pauli-Magnus C, Lang T, Meier Y, Zodan-Marin T, Jung D, Breymann C, Zimmermann R, Kenngott S, Beuers U, Reichel C, Kerb R, Penger A, Meier PJ, Kullak-Ublick GA
Sequence analysis of bile salt export pump (ABCB11) and multidrug resistance p-glycoprotein 3 (ABCB4, MDR3) in patients with intrahepatic cholestasis of pregnancy.
Pharmacogenetics. 2004 Feb;14(2):91-102., [PMID:15077010]
Abstract [show]
Intrahepatic cholestasis of pregnancy (ICP) is a liver disorder associated with increased risk of intrauterine fetal death and prematurity. There is increasing evidence that genetically determined dysfunction in the canalicular ABC transporters bile salt export pump (BSEP, ABCB11) and multidrug resistance protein 3 (MDR3, ABCB4) might be risk factors for ICP development. This study aimed to (i). describe the extent of genetic variability in BSEP and MDR3 in ICP and (ii). identify new disease-causing mutations. Twenty-one women with ICP and 40 women with uneventful pregnancies were recruited between April 2001 and April 2003. Sequencing of BSEP and MDR3 spanned 8-10 kb per gene and comprised the promoter region and 100-350 bp of the flanking intronic region around each exon. DNA sequencing of polymerase chain reaction fragments was performed on an ABI3700 capillary sequencer. MDR3 promoter activity of promoter constructs carrying different ICP-specific mutations was studied using reporter assays. A total of 37 and 51 variant sites were detected in BSEP and MDR3, respectively. Three non-synonymous sites in codons for evolutionarily conserved amino acids were specific for the ICP collective (BSEP, N591S; MDR3, S320F and G762E). Furthermore, four ICP-specific splicing mutations were detected in MDR3 [intron 21, G(+1)A; intron 25, G(+5)C and C(-3)G; and intron 26, T(+2)A]. Activity of the mutated MDR3 promoter was similar to that observed for the wild-type promoter. Our data further support an involvement of MDR3 genetic variation in the pathogenesis of ICP, whereas analysis of BSEP sequence variation indicates that this gene is probably less important for the development of pregnancy-associated cholestasis.
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No. Sentence Comment
8 Three nonsynonymous sites in codons for evolutionarily conserved amino acids were specific for the ICP collective (BSEP, N591S; MDR3, S320F and G762E).
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ABCB4 p.Gly762Glu 15077010:8:145
status: NEW136 1 , 1 Splicing 2 , 1 N591S 3 NA 4 3.7 Splicing 5 NA 6 9.0 7 , 1 8 , 1 9 , 1 10 1.7 G762E 11 , 1 12 2.6 13 2.8 14 4.5 15 2.9 Splicing 16 , 1 17 4.2 18 2.5 Splicing 19 2.3 20 1.4 S320F 21 , 1 ICP-specific variants are indicated with their respective variant number (Tables 1 and 2).
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ABCB4 p.Gly762Glu 15077010:136:83
status: NEW109 Non-synonymous changes newly observed as singletons or doubletons in our sample set coded for the following amino acid changes: S320F, E528D, G762E and T775M.
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ABCB4 p.Gly762Glu 15077010:109:142
status: NEW116 The ICP-specific variants included two non-synonymous sites (heterozygous : exon 18, G762E; homozygous : exon 19, S320F) and one synonymous site (exon 6, T459C).
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ABCB4 p.Gly762Glu 15077010:116:85
status: NEW142 Q R I K R I Q I D F H G I E H D T T E L H S I D D T L K I S E G I G D K R Q R K F F H A I L R G A V A G V T R I G G Q H L E K A Q K H L L G A E I F E YA R R T L I E G L S H A F K A H R D F H S H D Q D K H S T G A L A Q V Q G A T G T R L R S R H G A L L K R E I A E T A T S L T Q E R V Y H S E F L P Y R H S V Q K K I K D E L E A A G H E L A K A Y D A T Q G K K V Q E P I L I E A I S C Q Q R I A I E V V Q G L S L P A K L S H KL H A D T A L R T A K K A I H V V K E Y G K K F D A R V K Q Q R I L A P V F Q G G A V Q H T G H E Q H L K A A S C S S G V L L A Q L G I R H D G Y A G Q L S G G P R A H V P F G R S TT A D L L L I E I H A D L I Q I K Q A L L G V V H S F Y S L Q R E F L Q V T S K G K L H V Q H I D Q S V V E R V G D K H V V F H Y P V K E TE E D L A S T T I H R L S T A E S Y S D I D F K E L L L D G Q E A A K A A A V E L P K K Y F G H I T F E Y L A TE E V V K E S Q E R T C I V G D A L K R A H H I P I F A P L G V T K G L P K D Y F H D L E R H A T G H K P T S E L G I S S K F D G V T K T K K R K H I F R Y S D H Q L T L D K A A Q K A E G V F V D K G A T H F S S L S F H V H L L P K K H T R E E E F P I H A Y Y Y Y H T D S R G H K A I I E S K Q Q K C H I F VG P G D D A F R F C G H R F R D V G A HY L I V H G Y G H Q V F G I GE L H H P S G L G I A H A T T H G H S LFL G A G L A Y I A T L V L S P I I I G HT T V F H S I L F G A F I V G Q S A P C A F S LI L F L F I I S G F T F F L Q G F T F G F A T F V G H F V Y G S H L A F A A S Y Y L L I F I FV A F S P G L Q G I A H A T V C G A H L I A L I L S I S F H I Y A T L L L V F I A IS F G A V A LV H AG S S F G I T Q A F H Y F S Y A L L L V V A I I P V S A I V G A Q H G T G I I I S F I F V V YG I A H F Q Q F A G F I V G F I A K A Y E K D L S F A S L A E A R E A H E K G I K I K A ISAH I E E T D L D H R V T E H K K E S V K F Y V G D K A A T V A H R L S A L L EI K H P A H G H Q K S L D C L A Q V E A D F G A I V V Q G S H S S T Q H H S E F E L H R G R T T I A E E G EE H F L R S K R K L K H S Q H S T QQ QG ID A IVK K G G S L L E A T S Q D R I A I R Q P K I L L A H A V L A V E R G A G P K F D T L Q L E V A K K R I E Y A H A F H H T K D E V H C Y G R G I E E S V V G Q T S F L V P T I H L R E I Y D R H F H V I Q P Y L R Q D I I T G E D H D S T V Q L T G S G C G K S V K H L G K L V Q G S Q V T A R H V K I A V F S Y P S H D P H G E K L G K I S D H E KAGLHF QIIILS F S D I K P H H D I I D V P P V H A E L G D T E V F V I I A A G R A H A F A D P K V L K F H K T E H L R R S L Q T G A Q H IAL V I T S H A I G L L A A S H A V L V V V S Q H T F A A L S K E Y I K T175A E528D T775M R652G S Cytoplasm R T G762E S320F Extracellular K Fig. 2 Secondary structure of multidrug resistance protein 3 with non-synonymous coding region genetic variants.
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ABCB4 p.Gly762Glu 15077010:142:2553
status: NEW176 Out of the coding region changes, two were newly identified non-synonymous mutations located in highly conserved regions of the protein (S320F and G762E).
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ABCB4 p.Gly762Glu 15077010:176:147
status: NEW[hide] Combined mutations of canalicular transporter prot... Gastroenterology. 2006 Aug;131(2):624-9. Keitel V, Vogt C, Haussinger D, Kubitz R
Combined mutations of canalicular transporter proteins cause severe intrahepatic cholestasis of pregnancy.
Gastroenterology. 2006 Aug;131(2):624-9., [PMID:16890614]
Abstract [show]
Intrahepatic cholestasis of pregnancy (ICP) is a cholestatic disorder that usually develops in the third trimester of pregnancy and persists until delivery. The cause of ICP remains elusive, but there is evidence that mutations in the canalicular ABC transporter phospholipid flippase (MDR3) and in the bile salt export pump (BSEP) can predispose for the development of ICP. MDR3 and BSEP were investigated by gene sequencing and immunofluorescence microscopy in a patient with severe ICP of early onset. ICP was diagnosed in a patient in the first trimester of pregnancy with severe pruritus, elevated levels of bile salts, and 48-fold elevation of transaminase levels. A liver biopsy specimen showed diminished canalicular expression of the bile salt export pump BSEP, while the expression and localization of the phospholipid flippase MDR3 was normal. Gene sequencing revealed a homozygous MDR3 gene mutation (S320F). The patient was also homozygous for the common BSEP polymorphism V444A. Treatment with ursodeoxycholate normalized transaminase levels but could not prevent further elevation of bile salt levels and preterm delivery. The combined homozygous alterations of the canalicular transporters may explain the early onset and severity of ICP in this patient. The common BSEP polymorphism V444A accounts for the reduced canalicular BSEP expression. Reduced bile salt secretion through BSEP may explain the persistence of elevated bile salt levels and incomplete efficacy of ursodeoxycholate treatment.
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No. Sentence Comment
58 Two ICP-specific nonsynonymous SNPs were detected in the MDR3 gene (S320F and G762E).6 In the BSEP gene, one ICP-specific SNP was found (N591S).6 Another nucleotide exchange from T to C at position Figure 2.
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ABCB4 p.Gly762Glu 16890614:58:78
status: NEW[hide] Intrahepatic cholestasis of pregnancy: three novel... Aliment Pharmacol Ther. 2006 Jun 1;23(11):1649-53. Floreani A, Carderi I, Paternoster D, Soardo G, Azzaroli F, Esposito W, Variola A, Tommasi AM, Marchesoni D, Braghin C, Mazzella G
Intrahepatic cholestasis of pregnancy: three novel MDR3 gene mutations.
Aliment Pharmacol Ther. 2006 Jun 1;23(11):1649-53., [PMID:16696816]
Abstract [show]
BACKGROUND: The aetiology of intrahepatic cholestasis of pregnancy is unknown, but more than 10 different MDR3 gene mutations have recently been identified. AIM: To evaluate the genetic contribution of the MDR3 gene in the pathogenesis of intrahepatic cholestasis of pregnancy in Italian subjects. METHODS: We performed a multicentre prospective case-control study, enrolling 80 women with intrahepatic cholestasis of pregnancy at the third trimester of pregnancy and 80 pregnant women without intrahepatic cholestasis of pregnancy. Genomic DNA was extracted from peripheral venous blood leucocytes using standard procedures. The polymerase chain reaction was used to amplify exon 14 of the MDR3 gene and the polymerase chain reaction products were sequenced using a Big Dye Terminator Cycle Sequencing kit. RESULTS: Three novel non-synonymous heterozygous mutations in exon 14 were found (4%; E528D, R549H, G536R) among the 80 intrahepatic cholestasis of pregnancy patients, whereas the pregnant controls were all negative for exon 14 polymorphisms. The three patients involved had normal GGT and bilirubin, but high levels of both ALT and serum bile acids. One had cholesterol bile stones. The outcome of pregnancy was normal for two (with vaginal delivery), while foetal distress was recorded in the third. CONCLUSIONS: These three novel mutations add further information on the involvement of the MDR3 gene in intrahepatic cholestasis of pregnancy. As in other studies, we found only heterozygous mutations that could cause an impaired transport protein function, not its absence (which is responsible for more severe liver disease). Different genetic backgrounds might justify the presence of novel MDR3 gene mutations.
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No. Sentence Comment
35 MDR3 mutations reported in the literature Mutation (codon) Exon Reference (R144X) 6 Gendrot et al.5 481G>A (R150K) 6 Mu¨llenbach et al.6 426-432del (132) 6 DeVree et al.13 959C>T (S320F) 9 Rosmordurc et al.,14 Pauli-Magnus et al.9 (G535D) 14 Lucena et al.7 1669 C>A (A546D) 14 Dixon et al.4 1712 del T (571) 14 Jacquemin et al.8, 15 2285 G>A (G762E) 18 Pauli-Magnus et al.9 2901 C>T (R957X) 23 DeVree et al.13 conditions included an initial denaturation step at 94 °C for 5 min, followed by 40 cycles of denaturation at 94 °C for 30 s, annealing at 55 °C for 30 s and extension at 72 °C for 30 s.
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ABCB4 p.Gly762Glu 16696816:35:348
status: NEW