Background: Progressive familial intrahepatic cholestasis is a rare, heterogeneous group of liver disorders of autosomal recessive inheritance, characterised by an early onset of cholestasis with pruritus and malabsorption, which rapidly progresses, eventually culminating in liver failure. For children and their parents, PFIC is an extremely distressing disease. Significant pruritus can lead to severe cutaneous mutilation and may affect many activities of daily living through loss of sleep, irritability, poor attention, and impaired school performance.

Methods: Databases including MEDLINE and Embase were searched for publications on PFIC prevalence, incidence or natural history, and the economic burden or health-related quality of life of patients with PFIC. Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines were followed.

Results: Three systematic reviews and twenty-two studies were eligible for inclusion for the epidemiology of PFIC including a total of 2603 patients. Study periods ranged from 3 to 33 years. Local population prevalence of PFIC was reported in three studies, ranging from 9.0 to 12.0% of children admitted with cholestasis, acute liver failure, or splenomegaly. The most detailed data come from the NAPPED study where native liver survival of >15 years is predicted in PFIC2 patients with a serum bile acid concentration below 102 µmol/L following bile diversion surgery. Burden of disease was mainly reported through health-related quality of life (HRQL), rates of surgery and survival. Rates of biliary diversion and liver transplant varied widely depending on study period, sample size and PFIC type, with many patients have multiple surgeries and progressing to liver transplant. This renders data unsuitable for comparison.

Conclusion: Using robust and transparent methods, this systematic review summarises our current knowledge of PFIC. The epidemiological overview is highly mixed and dependent on presentation and PFIC subtype. Only two studies reported HRQL and mortality results were variable across different subtypes. Lack of data and extensive heterogeneity severely limit understanding across this disease area, particularly variation around and within subtypes.

Keywords: ABCB11; ABCB4; ATP8B1; Bile acid; NR1H4 and Myo5b; Pruritus; TJP2.

Pulmonary alveolar proteinosis (PAP) has been reported in rodents treated with nanoparticles (NPs). However, little is known about the type of NPs producing PAP and their toxicity mechanisms. Here, we assembled seven PAP-inducing NPs and TiO₂ NPs as a negative control. At 1 and 6 months after a single intratracheal instillation in rats, pulmonary inflammation and the gene expression of ATP-binding cassette (ABC) transporters and related genes were evaluated in separated alveolar macrophages (AMs). One month after intratracheal instillation, seven NPs (Eu₂O₃, In₂O₃, Pr₆O₁₁, Sm₂O₃, Tb₄O₇, and NiO) caused PAP, but only In₂O₃ NPs caused persistent PAP at 6 months after treatment. The levels of phospholipids, indicators of PAP, showed good correlations with the gene expression profile of five transporters (ABCA1, ABCB4, ABCB8, ABCG1, and ABCG4), which effluxing phospholipids in AMs. Among them, ABCG1 and ABCG4 might be key transporters involved in PAP development because both showed a negative correlation with the magnitude of PAP, while others might be compensatory transporters for PAP recovery, as they showed a positive correlation. In conclusion, the identification of seven PAP-producing NPs implies that PAP may be an emerging occupational disease and that ABCG1 and ABCG4 may be therapeutic targets for PAP.

Keywords: ABC transporter; Biomarker; Foamy macrophage; Occupational disease; Rare earth oxide.

Hypoxia is a complex microenvironmental condition known to regulate choline kinase α (CHKA) activity and choline transport through transcription factor hypoxia-inducible factor-1α (HIF-1α) and, therefore, may confound the uptake of choline radiotracer [¹⁸F]fluoromethyl-[1,2-²H₄]-choline ([¹⁸F]-D4-FCH). The aim of this study was to investigate how hypoxia affects the choline radiotracer dynamics. Three underlying mechanisms by which hypoxia could potentially alter the uptake of the choline radiotracer, [¹⁸F]-D4-FCH, were investigated: ¹⁸F-D4-FCH import, CHKA phosphorylation activity, and the efflux of [¹⁸F]-D4-FCH and its phosphorylated product [¹⁸F]-D4-FCHP. The effects of hypoxia on [¹⁸F]-D4-FCH uptake were studied in CHKA-overexpressing cell lines of prostate cancer, PC-3, and breast cancer MDA-MB-231 cells. The mechanisms of radiotracer efflux were assessed by the cell uptake and immunofluorescence in vitro and examined in vivo (n = 24). The mathematical modelling methodology was further developed to verify the efflux hypothesis using [¹⁸F]-D4-FCH dynamic PET scans from non-small cell lung cancer (NSCLC) patients (n = 17). We report a novel finding involving the export of phosphorylated [¹⁸F]-D4-FCH and [¹⁸F]-D4-FCHP via HIF-1α-responsive efflux transporters, including ABCB4, when the HIF-1α level is augmented. This is supported by a graphical analysis of human data with a compartmental model (M2T6k + k₅) that accounts for the efflux. Hypoxia/HIF-1α increases the efflux of phosphorylated radiolabelled choline species, thus supporting the consideration of efflux in the modelling of radiotracer dynamics.

Keywords: choline kinase; efflux; hypoxia.

Genotyping is conclusive for the diagnosis of progressive familial intrahepatic cholestasis type 3 (PFIC3). Here we report a Chinese patient of PFIC3 with compound mutations in the ABCB4 gene. Liver biopsy was performed on a 17-year-old male patient with intrahepatic cholestasis of unknown etiology. Liver histology findings are indicative of intrahepatic cholestasis with extensive fibrosis. Genotyping revealed c.175C>T (p.L59L) mutation in exon 4, c.504C>T (p.N168N) mutation in exon 6, c.711A>T (p.I237I) mutation in exon 8, c.874A>T (p.K292X) in exon 9 and a novel mutation, c.1804G>T (p.G602W) in exon 15. Based on these findings, the patient was diagnosed with PFIC3. The novel mutation p.G602W in exon 15 was predicted as probably damaging by PolyPhen-2 with a score of 0.986 (sensitivity: 0.54; specificity: 0.94) and was predicted to affect protein function with a SIFT score of 0.01.

OBJECTIVE

To explore the clinical and genetic characteristics of a family affected by genetic cholestasis.

METHODS

Clinical data of the patient was collected. Targeted exome sequencing was carried out to detect the pathogenic mutations. The results were confirmed by Sanger sequencing.

RESULTS

The patient, a 5-year-old boy, presented with severe cholestatic cirrhosis. Genetic analysis revealed that he has carried compound heterozygous mutations c.1006-2A>G and c.3580C>T (p.R1194X) of the ABCB4 gene, which were inherited from his father and mother, respectively. By structural prediction, the mutation c.3580C>T can give rise to a truncated multi-drug resistance protein 3 (MDR3).

CONCLUSIONS

The patient was diagnosed with progressive familial intrahepatic cholestasis type 3 (PFIC-3) based on clinical and molecular findings. Detection of novel mutations of the ABCB4 gene has provided valuable clues for the diagnosis and genetic counseling.

The Th2 cytokine IL-13 is involved in biliary epithelial injury and liver fibrosis in patients as well as in animal models. The aim of this study was to investigate IL-13 as a therapeutic target during short term and chronic intrahepatic cholestasis in an Abcb4-knockout mouse model (Abcb4^-/-). Lack of IL-13 protected Abcb4^-/- mice transiently from cholestasis. This decrease in serum bile acids was accompanied by an enhanced excretion of bile acids and a normalization of fecal bile acid composition. In Abcb4^-/-/IL-13^-/- double knockout mice, bacterial translocation to the liver was significantly reduced and the intestinal microbiome resembled the commensal composition in wild type animals. In addition, 52-week-old Abcb4^-/-IL-13^-/- mice showed significantly reduced hepatic fibrosis. Abcb4^-/- mice devoid of IL-13 transiently improved cholestasis and converted the composition of the gut microbiota towards healthy conditions. This highlights IL-13 as a potential therapeutic target in biliary diseases.

Keywords: Th2; bacterial translocation; bile acid; intestinal microbiome; liver fibrosis; tight junction.

Background & aims: Low-phospholipid-associated cholelithiasis (LPAC) syndrome, a rare genetic form of intrahepatic cholelithiasis in adults, is still poorly understood. We report the results of the largest-ever case-control study of patients with LPAC syndrome aiming to assess the prevalence, clinical features, and comorbidities of the disease.

Methods: We included all LPAC cases diagnosed between 2001 and 2016 in 11 French centres. Controls consisted of all patients who underwent a cholecystectomy for common gallstone disease in a single non-academic centre over 1 year. A logistic regression analysis was used to identify the clinical features associated with LPAC syndrome across several patient strata with increasing levels of diagnostic confidence. The ratio between the incident cases of LPAC syndrome and the total number of cholecystectomies for gallstones was used to assess the relative prevalence of the disease.

Results: In this study, 308 cases and 206 controls were included. LPAC syndrome accounted for 0.5-1.9% of all patients admitted with symptomatic gallstone disease. Age at first symptoms <40 years, absence of overweight, persistence of symptoms after cholecystectomy, intrahepatic micro- or macrolithiasis, common bile duct (CBD) lithiasis, and no history of cholecystitis were independently associated with LPAC diagnosis. ATP-binding cassette subfamily B member 4 (ABCB4) variants, present in 46% of cases, were associated with CBD lithiasis, chronic elevation of gamma-glutamyltransferase (GGT), and personal or family history of hepato-biliary cancer.

Conclusions: In this case-control study, LPAC syndrome accounted for approximately 1% of symptomatic cholelithiasis in adults. In addition to pre-established diagnostic criteria, normal weight, CBD lithiasis, and no history of cholecystitis were significantly associated with the syndrome. ABCB4 gene variations in patients with LPAC were associated with CBD lithiasis, chronic cholestasis, and a personal or family history of hepato-biliary cancer.

Lay summary: In the largest case-control study ever conducted in patients with LPAC syndrome, a rare genetic form of intrahepatic cholelithiasis in young adults, LPAC syndrome was found in approximately 1% of all patients admitted to the hospital for symptomatic gallstones and, in addition to the pre-established characteristics of the syndrome (age at first symptoms <40 years, recurrence of symptoms after cholecystectomy, and/or imaging evidence of intrahepatic microlithiasis), was associated with lower BMI, higher prevalence of common bile duct stones, and lower incidence of acute cholecystitis. ABCB4 gene variants, which were detected in about half of cases, were associated with common bile duct stones and a personal or family history of hepato-biliary cancer.

Keywords: ABCB4; ABCB4, ATP-binding cassette subfamily B member 4; CBD, common bile duct; Cancer; Cholestasis; ERCP, endoscopic retrograde cholangiopancreatography; FDR, false discovery rate; GGT, gamma-glutamyltransferase; ICP, intrahepatic cholestasis of pregnancy; LPAC; LPAC, low-phospholipid-associated cholelithiasis; MRCP, magnetic resonance cholangiopancreatography; Metabolic syndrome; Pregnancy; UDCA, ursodeoxycholic acid.

BACKGROUND

Progressive familial intrahepatic cholestasis type 3 (PFIC3) is a chronic autosomal recessive disorder characterized by a wide spectrum of clinical severity generally related to the degree of pathogenicity of the causal sequence variation in ABCB4 gene.

METHODS

The present study reports the molecular investigation by Next Generation Sequencing (NGS) of five related patients with PFIC3 disease followed by bioinformatic analysis. A biochemical follow-up is also performed to assess the response of the ursodeoxycholic acid treatment.

RESULTS

The molecular results revealed complex genotype in homozygous state in all patients including a pathogenic c.1436C>> T (P479L) variation in the ABCB4 gene and two well-known polymorphisms, the V444A in ABCB11 gene and the D19H in the ABCG8 gene. Although the presence of the same genetic background, all patients present the disease at different ages and clinical signs with a variable degree of clinical severity at diagnosis. Additionally, a differential outcome to the treatment has been pointed out.

CONCLUSIONS

Our results provide evidence regarding the putative intervention of modifier factors in the phenotypic variability reported for the first time in the PFIC3 disease and highlight the importance of an early administration of the UDCA as a good solution to ovoid the disease progression.

Progressive familial intrahepatic cholestasis is caused by mutations in the ABCB4 gene and belongs to the family of familial intrahepatic cholestais disorders inherited in an autosomal recessive pattern. To date, about 200 patients with various hepatobiliary disorders associated with ABCB4 gene mutations have been described in the literature. The aim of this manuscript was to describe the pathogenesis, clinical presentation, diagnostic process and treatment of progressive familial intrahepatic cholestais type 3, based on the literature review.

A boy exhibiting conjugated hyperbilirubinemia from birth, with elevated serum gamma-glutamyl transpeptidase activity (GGT), developed liver failure unusually early (7mo); GGT concomitantly normalized. ABCB4 disease was suspected, but no ABCB4 lesion was found. The boy was instead homozygous for ABCB11 variant c.1213 T>C (p.(Cys405Arg)), which is predicted to affect protein function. Both ABCB4 and ABCB11 were normally expressed in the explanted liver, with intralobular cholestasis; however, large-duct sclerosing cholangiopathy and ductal-plate malformation also were present. The primary-cilium constituent doublecortin domain containing 2 (DCDC2) was not expressed. Co-existence of ABCB11 disease and DCDC2 disease was proposed. Further testing identified homozygosity for the canonical-receptor splice-site variant c.294-2A>G (p.?) in DCDC2. Our report emphasizes the need to integrate clinical, histological, and genetic data in patients with neonatal cholestasis.

Introduction: Intrahepatic cholestasis of pregnancy (ICP) is a heterogeneous group of liver disorders with a high recurrence rate. Patients with a history of ICP are at risk of developing contraceptive-induced cholestasis, especially if they harbour a biliary transporter mutation. We report the first case of drug-induced cholestasis associated with a contraceptive vaginal ring (CVR) in a patient with a prior history of ICP.

Presentation: Our patient was a women with a history of multiple pregnancies and spontaneous abortions and early and severe ICP. Two to four weeks after initiation of CVR, she developed signs and symptoms of cholestasis, which resolved after discontinuation of the CVR. A thorough investigation to exclude other plausible causes of cholestasis was performed, including a liver biopsy. Genetic testing revealed pathogenic mutations in both the ABCB11 and ABCB4 genes.

Discussion: Although a history of ICP used to be an absolute contraindication for oral contraceptive pills (OCP), recent studies suggest a lower risk of cholestasis associated with low-dose oestrogen pills (20-35 mcg compared to the original 50 mcg). No previous case report could confirm the theoretical risk associated with the use of a CVR, which delivers a very low estrogen dose (15 mcg). The two biliary transporter mutations identified in our case could potentially explain the patient's susceptibility to the cholestatic effect of oestrogen.

Conclusion: This case illustrates that CVR can trigger drug-induced cholestasis in a susceptible patient. While such cases should not discourage the trial of low-dose hormonal contraception in women with prior ICP, an appropriate follow-up is necessary to ensure early detection and treatment of drug-induced cholestasis.

Keywords: ABCB11; ABCB4; Contraceptive vaginal ring; Contraceptive-induced cholestasis; Drug-induced cholestasis; Intrahepatic cholestasis of pregnancy.

Cholelithiasis is a common problem in the Western world. Recurrent gallstones after cholecystectomy, however, are rare. We describe a case of a young woman with recurrent gallstones after a laparoscopic cholecystectomy leading to cholangitis during pregnancy. Additional testing revealed an ATP-binding cassette B4 (ABCB4) gene mutation. ABCB4 gene mutations leading to a multidrug resistance (MDR)3-P-glycoprotein deficiency are related to, among other diseases, recurrent cholelithiasis. Medical treatment consists of administering oral ursodeoxycholic acid. If untreated, MDR3 deficiency can lead to progressive liver failure requiring liver transplantation.

Progressive familial intrahepatic cholestasis type 3 is caused by a mutation in the ATP-binding cassette, subfamily B, member 4 (ABCB4) gene encoding multidrug resistance protein 3. A 32-year-old woman with a history of acute hepatitis at age 9 years was found to have jaundice during pregnancy in 2008, and was diagnosed as having intrahepatic cholestasis of pregnancy. In 2009, she underwent cholecystectomy for gallstones and chronic cholecystitis. However, itching and jaundice did not resolve postoperatively. She was admitted to our hospital with fatigue, jaundice, and a recently elevated γ-glutamyl transpeptidase level. Liver biopsy led to the diagnosis of biliary cirrhosis with ductopenia. Genetic testing revealed a pathogenic heterozygous mutation, ex13 c.1531G>> A (p.A511T), in the ABCB4 gene. Her father did not carry the mutation, but her mother's brother carried the heterozygous mutation. We made a definitive diagnosis of familial intrahepatic cholestasis type 3. Her symptoms and liver function improved after 3 mo of treatment with ursodeoxycholic acid.

Hydrophilic bile salts, ursodeoxycholate and hyodeoxycholate, have choleretic effects. ABCB4, a member of the ABC transporter family, is essential for the secretion of phospholipids from hepatocytes into bile. In this study, we assessed the effects of taurine- or glycine-conjugated cholate, ursodeoxycholate and hyodeoxycholate on the ABCB4-mediated phosphatidylcholine (PC) efflux using Abcb4 knockout mice and HEK293 cells stably expressing ABCB4. To evaluate the effects of bile salts on bile formation in Abcb4^+/+ or Abcb4^-/- mice, the bile was collected during intravenous infusion of saline or bile salts. The biliary PC secretion in Abcb4^+/+ mice was significantly increased by the infusions of all tested bile salts, especially taurohyodeoxycholate. On the other hand, Abcb4^-/- mice exhibited extremely low secretion of PC into bile, which was not altered by bile salt infusions. We also showed that the PC efflux from ABCB4-expressing HEK293 cells was stimulated by taurohyodeoxycholate much more strongly than the other tested bile salts. However, taurohyodeoxycholate did not restore the activities of ABCB4 mutants. Furthermore, light scattering measurements demonstrated a remarkable ability of taurohyodeoxycholate to form mixed micelles with PC. Therefore, the enhancing effect of taurohyodeoxycholate on the ABCB4-mediated PC efflux may be due to the strong mixed micelle formation ability.

Primary Sclerosing Cholangitis (PSC) is a progressive liver disease for which there is no effective medical therapy. PSC belongs to the family of immune-mediated biliary disorders and it is characterized by persistent biliary inflammation and fibrosis. Here, we explored the possibility of using extracellular vesicles (EVs) derived from human, bone marrow mesenchymal stromal cells (MSCs) to target liver inflammation and reduce fibrosis in a mouse model of PSC. Five-week-old male FVB.129P2-Abcb^4tm1Bor mice were intraperitoneally injected with either 100 µL of EVs (± 9.1 × 10⁹ particles/mL) or PBS, once a week, for three consecutive weeks. One week after the last injection, mice were sacrificed and liver and blood collected for flow cytometry analysis and transaminase quantification. In FVB.129P2-Abcb4^tm1Bor mice, EV administration resulted in reduced serum levels of alkaline phosphatase (ALP), bile acid (BA), and alanine aminotransferase (ALT), as well as in decreased liver fibrosis. Mechanistically, we observed that EVs reduce liver accumulation of both granulocytes and T cells and dampen VCAM-1 expression. Further analysis revealed that the therapeutic effect of EVs is accompanied by the inhibition of NFkB activation in proximity of the portal triad. Our pre-clinical experiments suggest that EVs isolated from MSCs may represent an effective therapeutic strategy to treat patients suffering from PSC.

Keywords: fibrosis; inflammation; liver; mesenchymal stromal cells; therapy.

OBJECTIVE

To explore the pathogenesis of a child with growth retardation, liver damage and congenital heart disease.

METHODS

G-banded chromosomal karyotyping, high-throughput next-generation sequencing (HT-NGS)and fluorescence in situ hybridization(FISH) were used to characterize the structural chromosomal aberration.

RESULTS

The child was found to have a karyotype of 46, XX, t(1;2) (q25;q21), t(7;20) (q21;p13). HT-NGS has detected a microdeletion at 2q21.3 and 7q21.11, respectively, which were verified by FISH.

CONCLUSIONS

Combined cytogenetic and molecular analysis can detect chromosome micrdeletions more precisely. The abnormalities of the child may be attributed to heterozygous deletion of ZEB2, ABCB4 and SEMA3A genes.

BACKGROUND

Lone atrial flutter (AFL) and atrial fibrillation (AF) are common and sometimes consequential cardiac conduction disorders with a strong heritability, as underlined by recent genome-wide association studies that identified genetic modifiers. Follow-up family-based genetic analysis also identified Mendelian transmission of disease alleles. Three affected members were exome-sequenced for the identification of potential causative mutations, which were subsequently validated by direct sequencing in the other 3 affected members. Taqman assay was then used to confirm the role of any mutation in an independent population of sporadic lone AFL/AF cases.

RESULTS

The family cluster analysis provided evidence of genetic inheritance of AFL in the family via autosomal dominant transmission. The exome-sequencing of 3 family members identified 7 potential mutations: of these, rs58238559, a rare missense genetic variant in the ATP-binding cassette sub-family B, member 4 (ABCB4) gene was carried by all affected members. Further analysis of 82 subjects with sporadic lone AF, 63 subjects with sporadic lone AFL, and 673 controls revealed that the allele frequency for this variation was significantly higher in cases than in the controls (0.05 vs. 0.01; OR = 3.73; 95% CI = 1.16-11.49; P = 0.013).

CONCLUSIONS

rs58238559 in ABCB4 is a rare missense variant with a significant effect on the development of AFL/AF.

Intrahepatic cholestasis of pregnancy (ICP) is defined as pruritus during pregnancy in the absence of primary skin lesions, combined with an increase in serum total bile salts and/or abnormal serum liver tests. This article provides an insight into the diagnostic and therapeutic considerations by presenting two cases. ICP usually presents around 34 weeks of gestation, but can be present early in pregnancy as described in a 32-year-old patient pregnant after in-vitro fertilization. DNA analysis showed a mutation in the ABCB4 gene, causing MDR3 deficiency. Ursodeoxycholic acid treatment seems to alleviate maternal pruritus and possibly reduces perinatal risks related to the severe form of ICP, defined as fasted serum bile salt levels of ≥ 40 μmol/l at any point during the pregnancy. Short-term rifampicin treatment can be considered in patients with persistent pruritus. Induction of labour is advised only after 37 weeks of gestation in patients with severe ICP.

Nuclear receptors (NR), the largest family of transcription factors, control many physiological and pathological processes. To gain insight into hepatic NR and their potential as therapeutic targets in cholestatis, we determined their expression in individual cell types of the mouse liver in normal and cholestatic conditions. Hepatocytes, cholangiocytes, hepatic stellate cells (HSC), sinusoidal endothelial cells (SEC) and Kupffer cells (KC) were isolated from the liver of mice with acute or chronic cholestasis (i.e. bile duct-ligated or Abcb4-/- mice, respectively) and healthy controls. The expression of 43 out of the 49 NR was evidenced by RT-qPCR in one or several liver cell types. Expression of four NR was restricted to non-parenchymal liver cells. In normal conditions, NR were expressed at higher levels in individual cell types when compared to total liver. Half of the NR expressed in the liver had maximal expression in non-parenchymal cells. After bile duct ligation, NR mRNA changes occurred mostly in non-parenchymal cells and mainly consisted in down-regulations. In Abcb4-/- mice, NR mRNA changes were equally frequent in hepatocytes and non-parenchymal cells. Essentially down-regulations were found in hepatocytes, HSC and cholangiocytes, as opposed to up-regulations in SEC and KC. While undetectable in total liver, Vdr expression was up-regulated in all non-parenchymal cells in Abcb4-/- mice. In conclusion, non-parenchymal liver cells are a major site of NR expression. During cholestasis, NR expression is markedly altered mainly by down-regulations, suggesting major changes in metabolic activity. Thus, non-parenchymal cells are important new targets to consider in NR-directed therapies.

BACKGROUND

Eculizumab-treated paroxysmal nocturnal hemoglobinuria (PNH) patients (pts) show a dramatic decrease in serum lactate dehydrogenase (LDH) activities and bilirubin concentrations. However, some pts remain hyperbilirubinemic, possibly indicating an inadequate response due to extravascular hemolysis.

METHODS

Mutation analyses of hepatocanalicular transporter/nuclear receptor variants (ABCB4, ABCB11, ATP8B1, NR1H4) were performed in eight (five of eight males; mean age 38 years [range 26-68 years]) out of the 174 pts with PNH/-clone at our department due to a persistent increase in total bilirubin concentrations (median 3.4 mg/dL; range 2.1-8.1 mg/dL) during chronic eculizumab treatment and normal/or slightly increased serum aminotransferase activities. Median observation time was 70.1 months (range 10.6-135.2 months). All pts were treated according to German PNH guidelines.

RESULTS

Homozygous and heterozygous procholestatic variants in the ABCB4, ABCB11, and ATP8B1 genes were identified in all eight pts. All carried the common ABCB4 c.787A>T polymorphism. The A(TA)7 TAA variant in the UGT1A1 promoter causing Gilbert syndrome was detected in three pts (5/8).

CONCLUSIONS

Hyperbilirubinemia in PNH pts treated with eculizumab might not only be due to an insufficient response but rather a combination of mutations in hepatocanalicular transporter variants, Gilbert syndrome, and extravascular hemolysis. Our findings warrant further studies concerning transporter and enzyme variants in PNH to determine their clinical significance.

The low-phospholipid-associated cholelithiasis (LPAC) syndrome is a form of symptomatic cholelithiasis occurring in young adults, characterized by recurrence of symptoms after cholecystectomy and presence of hepatolithiasis. The case refers to a healthy 39-year-old Caucasian male who presented with abdominal pain and jaundice. His blood tests showed conjugated hyperbilirubinemia and elevated liver enzymes (total bilirubin 6.65 mg/dL, γ-glutamyltransferase 699 IU/L) and abdominal computed tomography revealed dilation of common bile duct and left intrahepatic ducts. Magnetic resonance cholangiopancreatography identified choledocholithiasis, retrieved by endoscopic retrograde cholangiopancreatography, after which there was a worsening of jaundice (total bilirubin 23 mg/dL), which persisted for several weeks, possibly due to ciprofloxacin toxicity. After an extensive workup including liver biopsy, the identification of two foci of hepatolithiasis on reevaluation abdominal ultrasound raised the hypothesis of LPAC syndrome and the patient was started on ursodeoxycholic acid, with remarkable improvement. Genetic testing identified the mutation c.1954A>G (p.Arg652Gly) in ABCB4 gene (homozygous) and c.1331T>C (p.Val444Ala) in ABCB11 gene (heterozygous). In conclusion, we describe the unique case of an adult male with choledocholithiasis, hepatolithiasis, and persistent conjugated hyperbilirubinemia after retrieval of stones, fulfilling the criteria for LPAC syndrome and with possible superimposed drug-induced liver injury, in whom ABCB4 and ABCB11 mutations were found, both of which had not been previously described in association with LPAC.