ABCMdb

ABCB4 p.Ala934Thr

Predicted by SNAP2:	C: D (85%), D: D (80%), E: D (75%), F: D (80%), G: D (91%), H: D (75%), I: D (66%), K: D (80%), L: D (75%), M: D (66%), N: D (63%), P: D (85%), Q: D (95%), R: D (75%), S: N (53%), T: D (91%), V: D (66%), W: D (80%), Y: D (95%),
Predicted by PROVEAN:	C: D, D: D, E: D, F: D, G: D, H: D, I: D, K: D, L: D, M: D, N: D, P: D, Q: D, R: D, S: N, T: D, V: D, W: D, Y: D,

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[hide] ABCB4 heterozygous gene mutations associated with ... Gastroenterology. 2008 Jul;135(1):131-41. Epub 2008 Mar 26. Ziol M, Barbu V, Rosmorduc O, Frassati-Biaggi A, Barget N, Hermelin B, Scheffer GL, Bennouna S, Trinchet JC, Beaugrand M, Ganne-Carrie N
ABCB4 heterozygous gene mutations associated with fibrosing cholestatic liver disease in adults.
Gastroenterology. 2008 Jul;135(1):131-41. Epub 2008 Mar 26., [PMID:18482588]

Abstract [show]
BACKGROUND & AIMS: Adenosine triphosphate-binding cassette subfamily B, member 4 (ABCB4) mutations have not been investigated in patients with unexplained cholestasis. We aimed to investigate ABCB4 mutations in adult patients with unexplained anicteric cholestasis and to describe liver injury associated with ABCB4 mutations. METHODS: Between February 2004 and March 2007, all adults with unexplained cholestasis despite multiple investigations including liver biopsy and 124 healthy volunteers had ABCB4 sequencing. Fibrosis, bile duct lesions, inflammatory infiltrate, activation of myofibroblasts and multidrug-resistant P-glycoprotein 3 (MDR3) immunostaining were assessed on patients' liver biopsy specimens. RESULTS: Thirty-two patients were included (23 females, 16-69 years of age). Eight different ABCB4 heterozygous mutations were found in 11 patients (34%). Seven of these mutations (exons 4, 6, 14, 18, 23) were never detected in the control group. One mutation (exon 15) was detected in 4 patients (12.5%) and 4 controls (3%). At the time of liver biopsy, the main clinical and biologic characteristics were similar in the 32 patients regardless of ABCB4 mutation. The histologic pattern in patients with a mutation consisted of portal fibrosis with ductular reaction and strong macrophagic infiltrate of portal tracts without significant periportal and lobular necroinflammatory lesions or cholangitis. Fibrosis score and macrophagic infiltration of portal tracts were significantly increased in patients with ABCB4 mutation (P = .01). Absence or reduced MDR3 canalicular immunostaining was demonstrated in all patients with ABCB4 mutations tested. CONCLUSIONS: Heterozygous ABCB4 mutations were detected in 34% of adults with unexplained cholestasis, for the most part without biliary symptoms, and could result in significant liver fibrosis.

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56 As described in Figure 1, 3 (T175A, R590Q, A934T) have been previously described in patients with LPAC or ICP.8,13 Conversely, 5 (R47X, V526F, A539T, R545G, I738L) have not been previously described.20 The frequency of each mutation is indicated in Figure 1. Login to comment
93 2800GϾT A934T 6 F 18 Yes (18 y) No No Yesb Missense 15 c. 1769GϾA R590Q 7 M 28 No - No - Missense 18c c. 2212AϾC I738L 8 F 52 Yes (51 y) Yes No No Missense 15 c. 1769GϾA R590Q 9 F 57 No - No No Missense 15 c. 1769GϾA R590Q 10 F 48 Yes (32 y) Yes Yes No Missense 14c c. Login to comment
94 1633AϾG R545G 11 M 29 No - No - Missense 14c c. Login to comment
57 As described in Figure 1, 3 (T175A, R590Q, A934T) have been previously described in patients with LPAC or ICP.8,13 Conversely, 5 (R47X, V526F, A539T, R545G, I738L) have not been previously described.20 The frequency of each mutation is indicated in Figure 1. Login to comment

[hide] Low phospholipid associated cholelithiasis: associ... Orphanet J Rare Dis. 2007 Jun 11;2:29. Rosmorduc O, Poupon R
Low phospholipid associated cholelithiasis: association with mutation in the MDR3/ABCB4 gene.
Orphanet J Rare Dis. 2007 Jun 11;2:29., [PMID:17562004]

Abstract [show]
Low phospholipid-associated cholelithiasis (LPAC) is characterized by the association of ABCB4 mutations and low biliary phospholipid concentration with symptomatic and recurring cholelithiasis. This syndrome is infrequent and corresponds to a peculiar small subgroup of patients with symptomatic gallstone disease. The patients with the LPAC syndrome present typically with the following main features: age less than 40 years at onset of symptoms, recurrence of biliary symptoms after cholecystectomy, intrahepatic hyperechoic foci or sludge or microlithiasis along the biliary tree. Defect in ABCB4 function causes the production of bile with low phospholipid content, increased lithogenicity and high detergent properties leading to bile duct luminal membrane injuries and resulting in cholestasis with increased serum gamma-glutamyltransferase (GGT) activity. Intrahepatic gallstones may be evidenced by ultrasonography (US), computing tomography (CT) abdominal scan or magnetic resonance cholangiopancreatography, intrahepatic hyperechogenic foci along the biliary tree may be evidenced by US, and hepatic bile composition (phospholipids) may be determined by duodenoscopy. In all cases where the ABCB4 genotyping confirms the diagnosis of LPAC syndrome in young adults, long-term curative or prophylactic therapy with ursodeoxycholic acid (UDCA) should be initiated early to prevent the occurrence or recurrence of the syndrome and its complications. Cholecystectomy is indicated in the case of symptomatic gallstones. Biliary drainage or partial hepatectomy may be indicated in the case of symptomatic intrahepatic bile duct dilatations filled with gallstones. Patients with end-stage liver disease may be candidates for liver transplantation.

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64 In addition, LPAC syndrome was observed in patients exhibiting the same or similar nonsense or missense mutations: in a mother and her elder son with an identical heterozygous nonsense mutation (1327insA); in independent patients from non-consanguineous families with the same homozygous missense mutation (Ser320Phe or Ala934Thr), while their heterozygous parents were asymptomatic; in patients with a similar nonsense mutation (1006-1016insT and 1006-1016delT) and in unrelated patients with the same missense mutations (Pro1161Ser). Login to comment

[hide] Function and pathophysiological importance of ABCB... Pflugers Arch. 2007 Feb;453(5):601-10. Epub 2006 Apr 19. Oude Elferink RP, Paulusma CC
Function and pathophysiological importance of ABCB4 (MDR3 P-glycoprotein).
Pflugers Arch. 2007 Feb;453(5):601-10. Epub 2006 Apr 19., [PMID:16622704]

Abstract [show]
Like several other ATP-binding cassette (ABC) transporters, ABCB4 is a lipid translocator. It translocates phosphatidylcholine (PC) from the inner to the outer leaflet of the canalicular membrane of the hepatocyte. Its function is quite crucial as evidenced by a severe liver disease, progressive familial intrahepatic cholestasis type 3, which develops in persons with ABCB4 deficiency. Translocation of PC makes the phospholipid available for extraction into the canalicular lumen by bile salts. The primary function of biliary phospholipid excretion is to protect the membranes of cells facing the biliary tree against these bile salts: the uptake of PC in bile salt micelles reduces the detergent activity of these micelles. In this review, we will discuss the functional aspects of ABCB4 and the regulation of its expression. Furthermore, we will describe the clinical and biochemical consequences of complete and partial deficiency of ABCB4 function.

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141 Canalicular lipid transport defects can cause gallstone formation Cholesterol supersaturation of bile, which occurs in a large proportion of humans, leads to the formation of cholesterol Walker B; L556R 571del Truncation PFIC3 LPAC ICP 27 splice Truncation 132 del Truncation TM 2; W138R TM 12; 981 del Truncation Linker; Q636X Truncation TM 11; R957X Truncation TM 6; S346I E395G Walker B; I541F TM 12; G983S Walker A; V425M Walker A; T424A Walker B; D564G TM 7; F711S 180 del truncation 336 delT truncation Exon 22-23 del truncation F165I T175A TM 5; M301T TM 5; S320F 336 insT truncation Walker A; 432 insA truncation E528D L591Q W658stop 757 insT R788E A934T P1161S TM 5; S320F TM 8; G762ER144X Walker B; A546D Walker B; G535AALL 96 del Truncation Walker B; L556R 571del Truncation PFIC3 LPAC ICP 27 splice Truncation 132 del Truncation TM 2; W138R TM 12; 981 del Truncation Linker; Q636X Truncation TM 11; R957X Truncation TM 6; S346I E395G Walker B; I541F TM 12; G983S Walker A; V425M Walker A; T424A Walker B; D564G TM 7; F711S 180 del truncation 336 delT truncation Exon 22-23 del truncation F165I T175A TM 5; M301T TM 5; S320F 336 insT truncation Walker A; 432 insA truncation E528D L591Q W658stop 757 insT R788E A934T P1161S TM 5; S320F TM 8; G762ER144X Walker B; A546D Walker B; G535AALL 96 del Truncation Fig. 3 Summary of the known mutations and their localization in the protein, as identified in patients with PFIC type 3, LPAC syndrome (intrahepatic gallstone formation), and intrahepatic cholestasis of pregnancy (ICP). Login to comment

[hide] ABCB4 gene mutation-associated cholelithiasis in a... Gastroenterology. 2003 Aug;125(2):452-9. Rosmorduc O, Hermelin B, Boelle PY, Parc R, Taboury J, Poupon R
ABCB4 gene mutation-associated cholelithiasis in adults.
Gastroenterology. 2003 Aug;125(2):452-9., [PMID:12891548]

Abstract [show]
BACKGROUND & AIMS: We recently put forward arguments in favor of ABCB4 gene (adenosine triphosphate-binding cassette, subfamily B, member 4) defects as a risk factor for symptomatic cholelithiasis in adults. In this study, we characterized ABCB4 gene mutations in a series of patients with symptomatic cholelithiasis to determine the genetic basis and the clinical phenotype of ABCB4 gene mutation-associated cholelithiasis. METHODS: We analyzed the entire ABCB4 gene coding sequences in a first group of 32 patients who had a clinical history compatible with the syndrome previously described, in a second group of 28 patients who presented with a classic gallstone disease that justified a cholecystectomy, and in a third group of 33 patients without a history of cholelithiasis. RESULTS: We identified both heterozygous and homozygous ABCB4 gene point mutations in 18 of 32 (56%) patients who presented with clinical criteria of the syndrome, whereas no mutation was detected in the 2 other groups of patients (P < 0.001). Three independent clinical features were strongly associated with point mutations: recurrence of symptoms after cholecystectomy (odds ratio, 8.5); intrahepatic hyperechoic foci, intrahepatic sludge, or microlithiasis (odds ratio, 6.1); and age <40 years at the onset of symptoms (odds ratio, 3.0). ABCB4 gene point mutations were detected exclusively in the patients who showed 2 or 3 of these clinical features. CONCLUSIONS: Our results show that ABCB4 gene mutations represent a major genetic risk factor in a symptomatic and recurring form of cholelithiasis in young adults.

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68 ABCB4 Gene Mutations in Patients With LPAC Syndrome Gene position Location and nucleotide change Peptide change Protein domain Status 6 495T3A Phe165Ile First intracellular loop Heterozygous 523T3C Thr175Ala between TM2 and TM3 Heterozygous 9 902T3C Met301Thr TM5 Heterozygous 959C3T Ser320Phe TM5 Homozygous 10 1007-1015insT 355Stop TM6 Heterozygous 1007-1015delT 341Stop TM6 Heterozygous 12 1327insA 447Stop Close to NBD11 Heterozygous 14 1584G3C Glu528Asp Close to NBD11 Heterozygous 15 1772T3A Leu591Gln Third intracellular loop Homozygous 17 1973G3A Try658Stop Third intracellular loop linker domain Heterozygous 18 2270-2273insT 793Stop Fourth intracellular loop between TM8 and TM9 Heterozygous 19 2363G3T Arg788Glu Fourth intracellular loop between TM8 and TM9 Heterozygous 23 2800G3T Ala934Thr Fifth intracellular loop between TM10 and TM11 Homozygous 26 3481C3T Pro1161Ser Close to NBD2 Heterozygous NOTE. The A of ATG of the initiator Met codon was denoted as "nucleotide ϩ 1." Login to comment
105 In addition, the LPAC syndrome was observed in patients with similar nonsense or missense mutations: in a mother and her elder son with an identical heterozygous nonsense mutation (1327insA); in patients from nonconsanguineous families with the same homozygous missense mutation (Ser320Phe or Ala934Thr) with asymptomatic heterozygous parents; in patients with a similar nonsense mutation (1006-1016insT and 1006-1016delT); and in unrelated patients with the same missense mutations (Pro1161Ser). Login to comment

[hide] Progressive familial intrahepatic cholestasis type... J Hepatol. 2003 May;38(5):693-4. Ganne-Carrie N, Baussan C, Grando V, Gaudelus J, Cresteil D, Jacquemin E
Progressive familial intrahepatic cholestasis type 3 revealed by oral contraceptive pills.
J Hepatol. 2003 May;38(5):693-4., [PMID:12713886]

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12 C) predicting abnormal splicing of coding sequence and a heterozygous missense mutation in exon 23 (A934T) [1,4]. Login to comment
13 C) predicting abnormal splicing of coding sequence and a heterozygous missense mutation in exon 23 (A934T) [1,4]. Login to comment