Efficacy and safety of odevixibat in patients with Alagille syndrome (ASSERT): a phase 3, double-blind, randomised, placebo-controlled trial.

BACKGROUND: In patients with Alagille syndrome, cholestasis-associated clinical features can include high serum bile acids and severe pruritus that can necessitate liver transplantation. We aimed to evaluate the efficacy and safety of the ileal bile acid transporter inhibitor odevixibat versus placebo in patients with Alagille syndrome. METHODS: The ASSERT study was a phase 3, double-blind, randomised, placebo-controlled trial that enrolled patients at 21 medical centres or hospitals in ten countries (Belgium, France, Germany, Italy, Malaysia, the Netherlands, Poland, Türkiye, the UK, and the USA). Eligible patients had a genetically confirmed diagnosis of Alagille syndrome, a history of significant pruritus, and elevated serum bile acids. Patients were randomly assigned (2:1) to receive oral odevixibat 120 µg/kg per day or placebo for 24 weeks (in a block size of six and stratified by age: <10 years and ≥10 years to <18 years) via a web-based system. Patients, clinicians, study staff, and people analysing the data were masked to treatment allocation. The primary efficacy endpoint was change in caregiver-reported scratching score (on the PRUCISION instrument; range 0-4) from baseline to weeks 21-24. The prespecified key secondary efficacy endpoint was change in serum bile acid concentration from baseline to the average of weeks 20 and 24. Outcomes were analysed in patients who received at least one dose of study drug (the full analysis set for efficacy outcomes and the safety analysis set for safety outcomes). This trial is registered on ClinicalTrials.gov (NCT04674761) and EudraCT (2020-004011-28), and is completed. FINDINGS: Between Feb 26, 2021, and Sept 9, 2022, 52 patients were randomly assigned to receive odevixibat (n=35) or placebo (n=17), all of whom were included in the analysis sets. The median age was 5·5 years (IQR 3·2 to 8·9). 27 (52%) of 52 patients were male and 25 (48%) were female. The mean scratching score was elevated at baseline in both groups (2·8 [SD 0·5] for odevixibat vs 3·0 [0·6] for placebo). Mean scratching scores at weeks 21-24 were 1·1 (0·9) for odevixibat and 2·2 (1·0) for placebo, representing a least-squares (LS) mean change of -1·7 (95% CI -2·0 to -1·3) for odevixibat and -0·8 (-1·3 to -0·3) for placebo, which was significantly greater for odevixibat than for placebo (difference in LS mean change from baseline -0·9 [95% CI -1·4 to -0·3]; p=0·0024). Odevixibat also resulted in significantly greater reductions in mean serum bile acids from baseline versus placebo (237 µmol/L [SD 115] with odevixibat vs 246 µmol/L [121] with placebo) to the average of weeks 20 and 24 (149 µmol/L [102] vs 271 µmol/L [167]; LS mean change -90 µmol/L [95% CI -133 to -48] with odevixibat vs 22 µmol/L [-35 to 80] with placebo; difference in LS mean change -113 µmol/L [95% CI -179 to -47]; p=0·0012). The most common treatment-emergent adverse events were diarrhoea (ten [29%] of 35 patients in the odevixibat group vs one [6%] of 17 in the placebo group) and pyrexia (eight [23%] vs four [24%]). Seven patients had serious treatment-emergent adverse events during the treatment period: five (14%) in the odevixibat group and two (12%) in the placebo group. No patients discontinued treatment and there were no deaths. INTERPRETATION: Odevixibat could be an efficacious non-surgical intervention to improve pruritus, reduce serum bile acids, and enhance the standard of care in patients with Alagille syndrome. Longer-term safety and efficacy data of odevixibat in this population are awaited from the ongoing, open-label ASSERT-EXT study. FUNDING: Albireo Pharma, an Ipsen company.

Interim results from an ongoing, open-label, single-arm trial of odevixibat in progressive familial intrahepatic cholestasis.

Background & Aims: PEDFIC 2, an ongoing, open-label, 72-week study, evaluates odevixibat, an ileal bile acid transporter inhibitor, in patients with progressive familial intrahepatic cholestasis. Methods: PEDFIC 2 enrolled and dosed 69 patients across two cohorts; all received odevixibat 120 µg/kg per day. Cohort 1 comprised children from PEDFIC 1, and cohort 2 comprised new patients (any age). We report data through 15 July 2020, with Week 24 of PEDFIC 2 the main time point analysed. This represents up to 48 weeks of cumulative exposure for patients treated with odevixibat from the 24-week PEDFIC 1 study (cohort 1A) and up to 24 weeks of treatment for those who initiated odevixibat in PEDFIC 2 (patients who received placebo in PEDFIC 1 [cohort 1B] or cohort 2 patients). Primary endpoints for this prespecified interim analysis were change from baseline to Weeks 22-24 in serum bile acids (sBAs) and proportion of positive pruritus assessments (≥1-point drop from PEDFIC 2 baseline in pruritus on a 0-4 scale or score ≤1) over the 24-week period. Safety monitoring included evaluating treatment-emergent adverse events (TEAEs). Results: In cohort 1A, mean change from PEDFIC 1 baseline to Weeks 22-24 of PEDFIC 2 in sBAs was -201 µmol/L (p <0.0001). For cohort 1B and cohort 2, mean changes from odevixibat initiation to weeks 22-24 in sBAs were -144 and -104 µmol/L, respectively. The proportion of positive pruritus assessments in the first 24-week period of PEDFIC 2 was 33%, 56%, and 62% in cohorts 1A, 1B, and 2, respectively. Most TEAEs were mild or moderate. No drug-related serious TEAEs occurred. Conclusions: Odevixibat in patients with progressive familial intrahepatic cholestasis was generally well tolerated and associated with sustained reductions in sBAs and pruritus. Clinical Trials Registration: This study is registered at ClinicalTrials.gov (NCT03659916). Impact and Implications: Disrupted bile flow is a hallmark feature of patients with progressive familial intrahepatic cholestasis and can result in build-up of bile constituents in the liver with spill over into the bloodstream; other effects that patients can experience include extremely itchy skin, and because not enough bile reaches the gut, patients can have problems digesting food, which may lead to poor growth. Odevixibat is an orally administered medication that shunts bile acids away from the liver. The current study, called PEDFIC 2, suggested that odevixibat can improve the problematic signs and symptoms of progressive familial intrahepatic cholestasis and was generally safe for patients.

Genotype-phenotype relationships of truncating mutations, p.E297G and p.D482G in bile salt export pump deficiency.

Background & Aims: Bile salt export pump (BSEP) deficiency frequently necessitates liver transplantation in childhood. In contrast to two predicted protein truncating mutations (PPTMs), homozygous p.D482G or p.E297G mutations are associated with relatively mild phenotypes, responsive to surgical interruption of the enterohepatic circulation (siEHC). The phenotype of patients with a compound heterozygous genotype of one p.D482G or p.E297G mutation and one PPTM has remained unclear. We aimed to assess their genotype-phenotype relationship. Methods: From the NAPPED database, we selected patients with homozygous p.D482G or p.E297G mutations (BSEP1/1; n = 31), with one p.D482G or p.E297G, and one PPTM (BSEP1/3; n = 30), and with two PPTMs (BSEP3/3; n = 77). We compared clinical presentation, native liver survival (NLS), and the effect of siEHC on NLS. Results: The groups had a similar median age at presentation (0.7-1.3 years). Overall NLS at age 10 years was 21% in BSEP1/3 vs. 75% in BSEP1/1 and 23% in BSEP3/3 (p <0.001). Without siEHC, NLS in the BSEP1/3 group was similar to that in BSEP3/3, but considerably lower than in BSEP1/1 (at age 10 years: 38%, 30%, and 71%, respectively; p = 0.003). After siEHC, BSEP1/3 and BSEP3/3 were associated with similarly low NLS, while NLS was much higher in BSEP1/1 (10 years after siEHC, 27%, 14%, and 92%, respectively; p <0.001). Conclusions: Individuals with BSEP deficiency with one p.E297G or p.D482G mutation and one PPTM have a similarly severe disease course and low responsiveness to siEHC as those with two PPTMs. This identifies a considerable subgroup of patients who are unlikely to benefit from interruption of the enterohepatic circulation by either surgical or ileal bile acid transporter inhibitor treatment. Impact and implications: This manuscript defines the clinical features and prognosis of individuals with BSEP deficiency involving the combination of one relatively mild and one very severe BSEP deficiency mutation. Until now, it had always been assumed that the mild mutation would be enough to ensure a relatively good prognosis. However, our manuscript shows that the prognosis of these patients is just as poor as that of patients with two severe mutations. They do not respond to biliary diversion surgery and will likely not respond to the new IBAT (ileal bile acid transporter) inhibitors, which have recently been approved for use in BSEP deficiency.

Impact of Genotype, Serum Bile Acids, and Surgical Biliary Diversion on Native Liver Survival in FIC1 Deficiency.

BACKGROUND AND AIMS: Mutations in ATPase phospholipid transporting 8B1 (ATP8B1) can lead to familial intrahepatic cholestasis type 1 (FIC1) deficiency, or progressive familial intrahepatic cholestasis type 1. The rarity of FIC1 deficiency has largely prevented a detailed analysis of its natural history, effects of predicted protein truncating mutations (PPTMs), and possible associations of serum bile acid (sBA) concentrations and surgical biliary diversion (SBD) with long-term outcome. We aimed to provide insights by using the largest genetically defined cohort of patients with FIC1 deficiency to date. APPROACH AND RESULTS: This multicenter, combined retrospective and prospective study included 130 patients with compound heterozygous or homozygous predicted pathogenic ATP8B1 variants. Patients were categorized according to the number of PPTMs (i.e., splice site, frameshift due to deletion or insertion, nonsense, duplication), FIC1-A (n = 67; no PPTMs), FIC1-B (n = 29; one PPTM), or FIC1-C (n = 34; two PPTMs). Survival analysis showed an overall native liver survival (NLS) of 44% at age 18 years. NLS was comparable among FIC1-A, FIC1-B, and FIC1-C (% NLS at age 10 years: 67%, 41%, and 59%, respectively; P = 0.12), despite FIC1-C undergoing SBD less often (% SBD at age 10 years: 65%, 57%, and 45%, respectively; P = 0.03). sBAs at presentation were negatively associated with NLS (NLS at age 10 years, sBAs < 194 µmol/L: 49% vs. sBAs ≥ 194 µmol/L: 15%; P = 0.03). SBD decreased sBAs (230 [125-282] to 74 [11-177] µmol/L; P = 0.005). SBD (HR 0.55, 95% CI 0.28-1.03, P = 0.06) and post-SBD sBA concentrations < 65 µmol/L (P = 0.05) tended to be associated with improved NLS. CONCLUSIONS: Less than half of patients with FIC1 deficiency reach adulthood with native liver. The number of PPTMs did not associate with the natural history or prognosis of FIC1 deficiency. sBA concentrations at initial presentation and after SBD provide limited prognostic information on long-term NLS.

Genotype correlates with the natural history of severe bile salt export pump deficiency.

BACKGROUND & AIMS: Mutations in ABCB11 can cause deficiency of the bile salt export pump (BSEP), leading to cholestasis and end-stage liver disease. Owing to the rarity of the disease, the associations between genotype and natural history, or outcomes following surgical biliary diversion (SBD), remain elusive. We aimed to determine these associations by assembling the largest genetically defined cohort of patients with severe BSEP deficiency to date. METHODS: This multicentre, retrospective cohort study included 264 patients with homozygous or compound heterozygous pathological ABCB11 mutations. Patients were categorized according to genotypic severity (BSEP1, BSEP2, BSEP3). The predicted residual BSEP transport function decreased with each category. RESULTS: Genotype severity was strongly associated with native liver survival (NLS, BSEP1 median 20.4 years; BSEP2, 7.0 years; BSEP3, 3.5 years; p <0.001). At 15 years of age, the proportion of patients with hepatocellular carcinoma was 4% in BSEP1, 7% in BSEP2 and 34% in BSEP3 (p = 0.001). SBD was associated with significantly increased NLS (hazard ratio 0.50; 95% CI 0.27-0.94: p = 0.03) in BSEP1 and BSEP2. A serum bile acid concentration below 102 µmol/L or a decrease of at least 75%, each shortly after SBD, reliably predicted NLS of ≥15 years following SBD (each p <0.001). CONCLUSIONS: The genotype of severe BSEP deficiency strongly predicts long-term NLS, the risk of developing hepatocellular carcinoma, and the chance that SBD will increase NLS. Serum bile acid parameters shortly after SBD can predict long-term NLS. LAY SUMMARY: This study presents data from the largest genetically defined cohort of patients with severe bile salt export pump deficiency to date. The genotype of patients with severe bile salt export pump deficiency is associated with clinical outcomes and the success of therapeutic interventions. Therefore, genotypic data should be used to guide personalized clinical care throughout childhood and adulthood in patients with this disease.

Management of Hepatitis B Virus Infection and Prevention of Hepatitis B Virus Reactivation in Children With Acquired Immunodeficiencies or Undergoing Immune Suppressive, Cytotoxic, or Biological Modifier Therapies.

Reactivation of hepatitis B virus (HBV) is a known complication of immune-suppressive, cytotoxic, and biological modifier therapies in patients currently infected with HBV or who have had past exposure to HBV. Nowadays, newer and emerging forms of targeted biologic therapies are available for the management of rheumatologic conditions, malignancies, inflammatory bowel disease, dermatologic conditions and solid-organ, bone marrow, or haematologic stem cell transplant but there is currently a lack of a systematic approach to the care of patients with or at risk of HBV reactivation. The Hepatology Committee of the European Society of Pediatric Gastroenterology, Hepatology and Nutrition (ESPGHAN) together with a working group of ESPGHAN members with clinical and research expertise in viral hepatitis developed an evidence-based position paper on reactivation of HBV infection in children identifying pertinent issues addressing the diagnosis, prevention, and treatment of this condition. Relevant clinical questions were formulated and agreed upon by all the members of the working group. Questions were answered and positions were based on evidence resulting from a systematic literature search on PubMed and Embase from their inception to July 1, 2019. A document was produced and the working group and ESPGHAN Hepatology Committee members voted on each recommendation, using a formal voting technique. A recommendation was accepted provided upon agreement by at least 75% of the working group members. This position paper provides a comprehensive update on the diagnosis, prevention and treatment of HBV reactivation in children.

Treatment of Chronic Hepatitis C Virus Infection in Children: A Position Paper by the Hepatology Committee of European Society of Paediatric Gastroenterology, Hepatology and Nutrition.

OBJECTIVES: In 2017, the European Medicines Agency and the Food and Drug Administration approved the use of the fixed-dose combination of ledipasvir/sofosbuvir and of the combination of sofosbuvir and ribavirin for treatment of adolescents (12-17 years or weighing >35 kg) with chronic hepatitis C virus (HCV) genotype 1, 4, 5, and 6 and genotype 2 and 3 infections, respectively. Although trials with direct-acting antivirals are ongoing for younger children, the only available treatment in the United States and Europe for those <12 years is still the dual therapy of pegylated interferon and ribavirin. There is currently a lack of a systematic approach to the care of these patients. The Hepatology Committee of the European Society of Pediatric Gastroenterology, Hepatology and Nutrition developed an evidence-based position paper for the management of chronic HCV infection in children. METHODS: A systematic literature search and meta-analysis were performed using MEDLINE and Embase from June 1, 2007 to June 1, 2017. The approach of the Grading of Recommendations Assessment, Development and Evaluation was applied to evaluate outcomes. European Society of Pediatric Gastroenterology, Hepatology and Nutrition Committee members voted on each recommendation, using the nominal voting technique. RESULTS: The efficacy of the different direct-acting antivirals combinations tested was higher, the relapse and the treatment discontinuation rates lower when compared to pegylated interferon and ribavirin. CONCLUSIONS: This position paper addresses therapeutic management issues including goals, endpoints, indications, contraindications, and the optimal treatment regimen in children with chronic HCV infection.

Effects of new and emerging therapies on gastrointestinal outcomes in cystic fibrosis.

PURPOSE OF REVIEW: Several new therapeutic modalities have recently become available to be used in patients with cystic fibrosis such as potentiators, modulators, and probiotics. Although the effects on pulmonary function have been well documented, gastrointestinal outcomes have been addressed only rarely. RECENT FINDINGS: Both the potentiator (ivacaftor) and the potentiator/modulator combination (ivacaftor/lumacaftor) that are currently on the market have a positive effect on BMI. Young patients (2-5 years of age) with a gating mutation may show improvement of exocrine pancreatic function on ivacaftor. In this specific patient population this agent also seems to improve intestinal pH and reflux. The effect of these medications on other gastrointestinal outcomes, such as intestinal inflammation and cystic fibrosis liver disease, has not been described so far. Furthermore, the results of several trials suggest that probiotics might reduce intestinal inflammation. Finally, organoids might be used to predict in vitro the clinical effect of potentiators and modulators. SUMMARY: The effect of new interventions on the gastrointestinal outcomes studied so far is favourable. Future studies should address the effect on other gastrointestinal parameters.

Current and future therapies for inherited cholestatic liver diseases.

Familial intrahepatic cholestasis (FIC) comprises a group of rare cholestatic liver diseases associated with canalicular transport defects resulting predominantly from mutations in ATP8B1, ABCB11 and ABCB4. Phenotypes range from benign recurrent intrahepatic cholestasis (BRIC), associated with recurrent cholestatic attacks, to progressive FIC (PFIC). Patients often suffer from severe pruritus and eventually progressive cholestasis results in liver failure. Currently, first-line treatment includes ursodeoxycholic acid in patients with ABCB4 deficiency (PFIC3) and partial biliary diversion in patients with ATP8B1 or ABCB11 deficiency (PFIC1 and PFIC2). When treatment fails, liver transplantation is needed which is associated with complications like rejection, post-transplant hepatic steatosis and recurrence of disease. Therefore, the need for more and better therapies for this group of chronic diseases remains. Here, we discuss new symptomatic treatment options like total biliary diversion, pharmacological diversion of bile acids and hepatocyte transplantation. Furthermore, we focus on emerging mutation-targeted therapeutic strategies, providing an outlook for future personalized treatment for inherited cholestatic liver diseases.

Rescue of defective ATP8B1 trafficking by CFTR correctors as a therapeutic strategy for familial intrahepatic cholestasis.

BACKGROUND & AIMS: ATP8B1 deficiency is an autosomal recessive liver disease characterized by intrahepatic cholestasis. ATP8B1 mutation p.I661T, the most frequent mutation in European patients, results in protein misfolding and impaired targeting to the plasma membrane. Similarly, mutations in cystic fibrosis transmembrane conductance regulator (CFTR), associated with cystic fibrosis, impair protein folding and trafficking. The aim of this study was to investigate whether compounds that rescue CFTR F508del trafficking are capable of improving p.I661T-ATP8B1 plasma membrane expression. METHODS: The effect of CFTR corrector compounds on plasma membrane expression of p.I661T-ATP8B1 was evaluated by cell surface biotinylation and immunofluorescence. ATPase activity was evaluated of a purified analogue protein carrying a mutation at the matching position (p.L622T-ATP8A2). RESULTS: The clinically used compounds, 4-phenylbutyric acid (4-PBA), suberoylanilide hydroxamic acid (SAHA) and N-butyldeoxynojirimycin (NB-DNJ) improved p.I661T-ATP8B1 plasma membrane targeting. Compounds C4, C5, C13 and C17 also significantly increased plasma membrane expression of p.I661T-ATP8B1. SAHA and compound C17 upregulated ATP8B1 transcription. p.I661T-ATP8B1 was partly targeted to the canalicular membrane in polarized cells, which became more evident upon treatment with SAHA and/or C4. p.L622T-ATP8A2 showed phospholipid-induced ATPase activity, suggesting that mutations at a matching position in ATP8B1 do not block functionality. Combination therapy of SAHA and compound C4 resulted in an additional improvement of ATP8B1 cell surface abundance. CONCLUSIONS: This study shows that several CFTR correctors can improve trafficking of p.I661T-ATP8B1 to the plasma membrane in vitro. Hence, these compounds may be suitable to be part of a future therapy for ATP8B1 deficiency and other genetic disorders associated with protein misfolding. LAY SUMMARY: Compounds that improve the cellular machinery dealing with protein homeostasis (proteostasis) and allow for proper folding of proteins with (mild) missense mutations are called proteostasis regulators (Balch, Science 2008). Such compounds are potentially of high therapeutic value for many (liver) diseases. In this manuscript, we investigated whether compounds identified in screens as CFTR folding correctors are actually proteostasis regulators and thus have a broader application in other protein folding diseases. Using these compounds, we could indeed show improved trafficking to the (apical) plasma membrane of a mutated ATP8B1 protein, carrying the p.I661T missense mutation. This is the most frequently identified mutation in this rare cholestatic disorder. Importantly, ATP8B1 shows no similarity to CFTR. These data are important in providing support for the concept that rare, genetic liver diseases can potentially be treated using a generalized strategy.

Total biliary diversion as a treatment option for patients with progressive familial intrahepatic cholestasis and Alagille syndrome.

BACKGROUND: Progressive familial intrahepatic cholestasis (PFIC) with low gamma-glutamyl transpeptidase (GGT) and Alagille syndrome are associated with persistent cholestasis and severe pruritus. Various types of biliary diversion have been used to reduce this pruritus and prevent liver dysfunction. We report our experience concerning the efficacy and safety of total biliary diversion (TBD) as an additional treatment option. METHODS: TBD was performed in four PFIC patients and one patient with Alagille syndrome, and was accomplished by anastomosing a jejunal segment to the choledochal duct terminating as an end stoma, or by disconnecting the choledochal duct after previous cholecystojejunocutaneostomy. RESULTS: TBD resulted in a marked improvement of symptoms and biochemical parameters in all PFIC patients. Despite relief of pruritus, cholestasis persisted in the Alagille patient. During 5-15years of follow-up, no clinical signs of fat malabsorption such as diarrhea or weight loss were encountered. However, to maintain adequate levels of fat-soluble vitamins, especially of vitamin K, substantial supplementation was necessary. CONCLUSIONS: Total biliary diversion can be a useful surgical treatment option for patients with low-GGT PFIC and possibly also Alagille syndrome, when partial biliary diversion is insufficient. It can be performed without inducing clinical signs of fat malabsorption although individualized supplementation of fat-soluble vitamins with careful monitoring is warranted.

Analysis of aberrant pre-messenger RNA splicing resulting from mutations in ATP8B1 and efficient in vitro rescue by adapted U1 small nuclear RNA.

UNLABELLED: ATP8B1 deficiency is a severe autosomal recessive liver disease resulting from mutations in the ATP8B1 gene characterized by a continuous phenotypical spectrum from intermittent (benign recurrent intrahepatic cholestasis; BRIC) to progressive familial intrahepatic cholestasis (PFIC). Current therapeutic options are insufficient, and elucidating the molecular consequences of mutations could lead to personalized mutation-specific therapies. We investigated the effect on pre-messenger RNA splicing of 14 ATP8B1 mutations at exon-intron boundaries using an in vitro minigene system. Eleven mutations, mostly associated with a PFIC phenotype, resulted in aberrant splicing and a complete absence of correctly spliced product. In contrast, three mutations led to partially correct splicing and were associated with a BRIC phenotype. These findings indicate an inverse correlation between the level of correctly spliced product and disease severity. Expression of modified U1 small nuclear RNAs (snRNA) complementary to the splice donor sites strongly improved or completely rescued splicing for several ATP8B1 mutations located at donor, as well as acceptor, splice sites. In one case, we also evaluated exon-specific U1 snRNAs that, by targeting nonconserved intronic sequences, might reduce possible off-target events. Although very effective in correcting exon skipping, they also induced retention of the short downstream intron. CONCLUSION: We systematically characterized the molecular consequences of 14 ATP8B1 mutations at exon-intron boundaries associated with ATP8B1 deficiency and found that the majority resulted in total exon skipping. The amount of correctly spliced product inversely correlated with disease severity. Compensatory modified U1 snRNAs, complementary to mutated donor splice sites, were able to improve exon definition very efficiently and could be a novel therapeutic strategy in ATP8B1 deficiency as well as other genetic diseases.

Mutational analysis of ATP8B1 in patients with chronic pancreatitis.

BACKGROUND: Mutations in genes encoding cationic trypsinogen (PRSS1), pancreatic secretory trypsin inhibitor (SPINK1) and chymotrypsinogen C (CTRC) are associated with chronic pancreatitis. However, in many patients with a familial chronic pancreatitis pattern suggesting a genetic cause, no mutations in either of these genes can be found, indicating that other, still unknown, associated genes exist. In this respect ATP8B1 is an interesting candidate due to its strong expression in the pancreas, its supposed general function in membrane organization and the higher incidence of pancreatitis in patients with ATP8B1 deficiency. METHODS: We analyzed all 27 ATP8B1 coding exons and adjacent non-coding sequences of 507 chronic pancreatitis patients by direct sequencing. Exons that harbored possible relevant variations were subsequently sequenced in 1,027 healthy controls. RESULTS: In the exonic regions, 5 novel non-synonymous alterations were detected as well as 14 previously described alterations of which some were associated with ATP8B1 deficiency. However, allele frequencies for any of these variations did not significantly differ between patients and controls. Furthermore, several non-synonymous variants were exclusively detected in control subjects and multiple variants in the non-coding sequence were identified with similar frequencies in both groups. CONCLUSIONS: We did not find an association between heterozygous ATP8B1 variants and chronic pancreatitis in our cohort of patients with hereditary and idiopathic chronic pancreatitis.

Familial cholestasis: progressive familial intrahepatic cholestasis, benign recurrent intrahepatic cholestasis and intrahepatic cholestasis of pregnancy.

Progressive familial intrahepatic cholestasis (PFIC) type 1, 2 and 3 are due to mutations in ATP8B1, ABCB11 and ABCB4, respectively. Each of these genes encodes a hepatocanalicular transporter, which is essential for the proper formation of bile. Mutations in ABCB4 can result in progressive cholestatic disease, while mutations in ATP8B1 and ABCB11 can result both in episodic cholestasis, referred to as benign recurrent intrahepatic cholestasis (BRIC) type 1 and 2, as well as in progressive cholestatic disease. This suggests a clinical continuum and these diseases are therefore preferably referred to as ATP8B1 deficiency and ABCB11 deficiency. Similarly PFIC type 3 is designated as ABCB4 deficiency. Heterozygous mutations in each of these transporters can also be associated with intrahepatic cholestasis of pregnancy. This review summarizes the pathophysiology, clinical features and current as well as future therapeutic options for progressive familial- and benign recurrent intrahepatic cholestasis as well as intrahepatic cholestasis of pregnancy.

Neo-aortic valvar function after the arterial switch.

OBJECTIVES: The purpose of our study was to assess the prevalence and progression, during childhood and adolescence, of dilation of the neo-aortic root, and neo-aortic valvar regurgitation, and to identify risk factors for such dilation and regurgitation, after the arterial switch operation. METHODS: We included all patients who had undergone an arterial switch operation at The Children's Hospital of Philadelphia, and had been followed for a minimum of 4 years, and had at least 2 postoperative echocardiograms. Neo-aortic valvar regurgitation was quantitatively assessed, and measurements were made of the neo-aortic root at the level of the basal attachment of the leaflets, mid-sinusal level, and the sinutubular junction. RESULTS: We found 82 patients who satisfied the criterions for inclusion, of whom 52 patients had transposition with an intact ventricular septum, and 30 had either an associated ventricular septal defect or double outlet right ventricle. The median follow-up time was 8.8 years (4.1 to 16.4 years). The neo-aortic valve had been replaced in 1 patient. Of the patients, 3 had moderate, 66 had trivial to mild, and 12 had no neo-aortic valvar regurgitation at their most recent follow-up. The regurgitation had progressed by at least 1 grade in 38 of the 82 patients (46.4%). Neo-aortic dilation was noted at the basal attachment of the leaflets, and at mid-sinusal level, which was out of proportion to somatic growth. CONCLUSIONS: At mid-term follow-up, significant neo-aortic valve regurgitation is present in 3.7%, and trivial to mild regurgitation in 81.4% of patients. The regurgitation progressed in almost half of the patients over time. We also noted progressive dilation of the neo-aortic root out of proportion to somatic growth.

Benign recurrent intrahepatic cholestasis type 2 is caused by mutations in ABCB11.

BACKGROUND & AIMS: Progressive familial intrahepatic cholestasis (PFIC) and benign recurrent intrahepatic cholestasis (BRIC) are hereditary liver disorders; PFIC is characterized by severe progressive liver disease whereas BRIC patients have intermittent attacks of cholestasis without permanent liver damage. Mutations in ATP8B1 are present in PFIC type 1 and in a subset of BRIC patients. We hypothesized that a genetically distinct form of BRIC is associated with mutations in ABCB11. This gene encodes the bile salt export pump (BSEP) and is mutated in PFIC type 2. METHODS: Patients from 20 families were included; all had a normal ATP8B1 sequence. Sequencing of all 27 coding exons including the splice junctions of ABCB11 revealed 8 distinct mutations in 11 patients from 8 different families: one homozygous missense mutation (E297G) previously described in PFIC2 patients, 6 novel missense mutations, and one putative splice site mutation. RESULTS: In 12 families, no mutations in ATB8B1 or ABCB11 were detected. Pancreatitis is a known extrahepatic symptom in BRIC caused by ATP8B1 mutations, but was not present in BRIC patients with mutations in ABCB11. In contrast, cholelithiasis was observed in 7 of 11 BRIC patients with mutations in ABCB11, but has not been described in ATP8B1-affected BRIC patients. CONCLUSIONS: Mutations in ABCB11 are associated with BRIC, and consistent with the genetic classification of PFIC into 2 subtypes, we propose that this disorder be named BRIC type 2.

Neo-aortic root dilation and valve regurgitation up to 21 years after staged reconstruction for hypoplastic left heart syndrome.

OBJECTIVES: We sought to assess the prevalence and progression of neo-aortic root dilation and valvar regurgitation after staged reconstruction for hypoplastic left heart syndrome (HLHS). BACKGROUND: In HLHS, the pulmonary valve functions as the neo-aortic valve. Neo-aortic valve dysfunction has been observed after arterial switch operation and the Ross procedure. METHODS: Patients with HLHS born before January 1995 who had the Fontan operation and had serial echocardiograms were included. Echocardiograms were reviewed preoperatively, after each surgical reconstruction, and at most recent follow-up for neo-aortic root size and severity of neo-aortic regurgitation (AR). Potential risk factors for neo-aortic valve dysfunction were assessed. RESULTS: Fifty-three patients met inclusion criteria. Bidirectional superior cavopulmonary anastomosis as an interim procedure was performed in 39 patients (74%). Median duration of follow-up was 9.2 (range 5.1 to 21) years. During follow-up, the neo-aortic root progressively dilated out of proportion to body size over time, with 52 patients (98%) having a Z-score >2 at most recent follow-up. Neo-AR was present in 61% of patients at most recent follow-up, with progression over time in 26 patients (49%). However, neo-AR was more than mild in only three patients. Significantly larger neo-aortic root Z-scores were observed in patients with any degree of neo-AR at most recent follow-up. No other anatomic or clinical variables correlated with severity of neo-AR or root dilation. CONCLUSIONS: After staged reconstruction for HLHS, neo-aortic root dilation and neo-AR progress over time. Early volume unloading does not have a beneficial impact on dilation of the neo-aortic root. These findings raise concerns about neo-aortic valve function into adulthood.