Rare cholestatic childhood diseases:Advances in clinical care

Biliary atresia, severe FIC1 and severe BSEP deficiency (also known as PFIC1 and PFIC2) are rare cholestatic childhood diseases. The aim of this thesis was to identify novel targets of intervention for improving the prognosis of patients suffering these diseases. The studies conducted in this thesis demonstrate that national or global collaboration allows to obtain novel insights in the natural history of rare liver diseases and their responsiveness to specific treatments. These insights have already led to patient-tailored changes in treatments for these diseases and are expected to have more impact in the near future, not only for the care and counselling of individual patients but also for understanding the pathophysiology of these rare diseases. The studies underline the value, if not the necessity, of collaborative efforts of clinicians, authorities and patient advocates for improving the prognosis of patients with rare diseases and for the advancement of science

Defining the natural history of rare genetic liver diseases:Lessons learned from the NAPPED initiative

While rare diseases collectively affect similar to 300 million people worldwide, the prevalence of each disease concerns a relatively small number of patients. Usually, only limited data with regard to natural history are available. Multicenter initiatives are needed to aggregate data and answer clinically relevant research questions. In 2017, we launched the NAtural course and Prognosis of PFIC and Effect of biliary Diversion (NAPPED) consortium. In three years, NAPPED created a global network focused on rare genetic liver diseases in the Progressive Familial Intrahepatic Cholestasis (PFIC) spectrum. During these years, we have learned important lessons which we feel should be taken into account when initiating and leading a global consortium.First, it is essential to 'keep it simple' from the start. Research questions, case report forms (CRFs) and data acquisition should be limited and clear to stay focused and keep the workload low for new participants. Secondly, early rewards and research output are needed to keep momentum and motivation. Quick output can only follow a clean and simple design. Thirdly, the leading team should be in touch and accessible. Ideally, an involved PhD-candidate is appointed as primary contact person. Lastly, be inclusive and actively involve all participants the consortium's course.Global consortia are critical for personalized medicine in rare diseases. Also, they are essential for setting up trials to investigate generic drugs and personalized therapies. We hope to herewith stimulate others that are starting (or are planning to start) a global consortium, ultimately to help improve the care for patients with a rare disease.</p

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

Compound heterozygosity; Genotype; PhenotypeHeterocigosidad compuesta; Genotipo; FenotipoHeterozigositat composta; Genotip; FenotipBackground & 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.1. MD/PhD scholarship from the University of Groningen, Groningen, The Netherlands 2. ESPGHAN Networking Grant 2019 3. ChiLDReN and CTSA National Institutes of Health grants: Ann & Robert H. Lurie Children's Hospital, Chicago: U01DK062436; University of Colorado, Denver: U01DK62453, UL1 TR002535; Baylor college of Medicine, Houston: U01DK103149; Children's Hospital of Philadelphia, Philadelphia: U01DK062481, UL1TR000003; Children's Hospital of Pittsburgh, Pittsburgh: U01DK062466; University of California, San Francisco U01DK062500; University of California, San Francisco CTSI grant UL1TR001872; Riley Hospital for Children, Indianapolis: U01DK084536; Seattle Children’s Hospital, Seattle: DK084575; Children’s Hospital Los Angeles, California: U01DK084538. 4. Unrestrictive research grant from Albireo 5. Unrestrictive research grant from Mirum Pharmaceuticals. 6. C&W de Boer Stichting research grant

Gut Microbiota Composition of Biliary Atresia Patients Before Kasai Portoenterostomy Associates With Long-term Outcome

BACKGROUND AND AIMS: Biliary atresia (BA) is a cholestatic, fibro-obliterative cholangiopathy of unknown etiology. BA is primarily treated by a surgical approach, i.e. the Kasai portoenterostomy (KPE), to obtain clearance of jaundice (COJ). The gut microbiota (GM) composition has been associated with the course of several cholestatic liver diseases. It is largely unknown, however, whether GM composition associates with the outcome of KPE. We compared the GM composition of BA patients and controls and assessed if GM composition before KPE was related to COJ after KPE. METHODS: We compared feces of term born BA patients before KPE and controls (patients undergoing inguinal hernia repair) by 16S rRNA sequencing. Composition and alpha diversity of the GM were compared between BA and controls before KPE and after KPE, between patients with COJ vs. without COJ (total serum bilirubin < or ≥ 20 μmol/L < 6mo post-KPE). RESULTS: Alpha diversity was comparable between BA (n = 12, age 1.6[1.3-1.8]mo) and controls (n = 6, age 2.0[1.4-2.1]mo; P = 0.22). Compared to controls, BA patients had lower abundances of Bifidobacteriaceae (β=-1.98, P < 0.001) and Lachnospiraceae (β=-1.84, P = 0.007), and higher abundances of Streptococcus (β=1.13, P = 0.003). The alpha diversity prior to KPE correlated negatively with COJ (R = -0.63, P = 0.03). Lower alpha diversity pre-KPE was associated with COJ [+] (βlogit = -0.64, P = 0.04). We observed greater abundances of genus Acinetobacter (β=1.27, P = 0.03) and family Clostridiaceae (β=1.45, P = 0.03) and lower abundances of the family Enterobacteriaceae, (genera Klebsiella (β=-1.21, P = 0.01), Salmonella (β=-1.57, P = 0.02)) in COJ [+] vs. COJ [-]. CONCLUSIONS: The gut microbiota of biliary atresia patients prior to Kasai portoenterostomy associates with outcome, clearance of jaundice, suggestive of predictive and mechanistic roles of the gut microbiota composition in bile homeostasis

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

Background &amp; 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 &lt;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 &lt;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.</p

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. Homozygous p.D482G or p.E297G mutations are associated with relatively mild phenotypes, responsive to surgical interruption of the enterohepatic circulation (siEHC), in contrast to patients with two predicted protein truncating mutations (PPTM). 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 presentation, native liver survival (NLS), and 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 in their follow-up, NLS of BSEP1/3 was similar to BSEP3/3 patients, but considerably lower than BSEP1/1 patients (at age 10 years: 38%, 30%, and 71%, resp; P=0.003). After siEHC, BSEP1/3 and BSEP3/3 patients had similarly low NLS, while this was much higher in BSEP1/1 patients (10 years after siEHC, 27%, 14%, and 92%, resp.; P<0.001). Conclusions: BSEP deficiency patients with one p.E297G or p.D482G mutation and one PPTM have a similarly severe disease course and low responsiveness to siEHC as patients 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

The Natural Course of Bsep Deficiency: Results from the Global Napped- Consortium

Background: BSEP deficiency (BSEP-def), due to mutations in the ABCB11gene, is responsible for progressive familial intrahepatic cholestasis type 2. The ABCB11gene encodes the canalicular Bile Salt Export Pump (BSEP). BSEPdef patients typically present with pruritus and cholestasis in early life, that usually progresses to the need for liver transplantation (LTx). Patients may benefit from ursodeoxycholic acid (UDCA) or from surgical biliary diversion (SBD) techniques. We aim to better understand the natural course of BSEPdef and the efficacy of interventions. Methods: We present retrospective follow up data on patients with compound heterozygous or homozygous ABCB11mutations from 22 centers in Europe, North-America, Asia and Australia (the NAPPED-consortium,NAtural course and Prognosis of PFIC and Effect of biliary Diversion). In total 203 patients (53% males) wereincluded and categorized according to genotype: mild (at least one D482G or E297G mutation; n=68), moderate (at least one missense mutation, but not D482G or E297G; n=100) or severe (mutations leading to truncated or otherwise non-functional protein; n=35). Cox regression analysis was applied for the endpoints SBD and native liver survival (NLS) studying the association with gender, age at diagnosis, birth year, genotype category and SBD as a time-dependent factor for NLS. Continuous variables are expressed as median [range]. Results: Overall median age at first visit was 9 months [0-195] and at last follow up 5.5 years [0.1-31.4]. Use of UDCA at first visit was 47%. Overall SBD rates at five/ten years of age were 27/34%, mild category patients were more likely to have undergone SBD (HR mild vs severe = 5.4, 95%CI 1.7-17.6; p<0.01). Overall five/ten-year NLS was 63/46%. Age at diagnosis and genotype were associated with NLS, in contrast to sex and UDCA. NLS was significantly higher in SBD+ve than in SBD-ve patients (HR=0.44; 95%CI 0.23-0.88, p=0.007; Figure) after adjustment for age and genotype category. This effect was independent of mild or moderate BSEP mutationssignificantly associated with NLS (HR=0.76; 95%CI 0.07-7.88, p=0.81). Hepatocellular carcinoma (HCC) was diagnosed in 8% of all patients, at a median age 2.1 years [0.7 – 11.0], and was significantly associated with genotype: mild 3%; moderate 8%, severe 18% (p=0.04). The observed NLS at 18 years of age was 34%; for mild, moderate and severe patients 51%, 24% and 0%, respectively (p=0.004). Conclusion: The NAPPED consortium has generated the largest collection of data on patients with BSEP deficiency, allowing more detailed insights into the natural course of this disease. Only a third of BSEP patients reach adulthood with their native liver. The effect of surgical biliary diversion, native liver survival and the incidence of HCC were all associated with the severity category of the BSEP mutation

Effects of intentional motor actions on embodied language processing

Embodied theories of language processing suggest that this motor simulation is an automatic and necessary component of meaning representation. If this is the case, then language and action systems should be mutually dependent (i.e., motor activity should selectively modulate processing of words with an action-semantic component). In this paper, we investigate in two experiments whether evidence for mutual dependence can be found using a motor priming paradigm. Specifically, participants performed either an intentional or a passive motor task while processing words denoting manipulable and nonmanipulable objects. The performance rates (Experiment 1) and response latencies (Experiment 2) in a lexical-decision task reveal that participants performing an intentional action were positively affected in the processing of words denoting manipulable objects as compared to nonmanipulable objects. This was not the case if participants performed a secondary passive motor action (Experiment 1) or did not perform a secondary motor task (Experiment 2). The results go beyond previous research showing that language processes involve motor systems to demonstrate that the execution of motor actions has a selective effect on the semantic processing of words. We suggest that intentional actions activate specific parts of the neural motor system, which are also engaged for lexical-semantic processing of actionrelated words and discuss the beneficial versus inhibitory nature of this relationship. The results provide new insights into the embodiment of language and the bidirectionality of effects between language and action processing

The Natural Course of FIC1 Deficiency: Results from the Napped-Consortium

Background: Severe deficiency of FIC1 (FIC1-def) is due to mutations in the ATP8B1gene, and is responsible for progressive familial intrahepatic cholestasis type 1. The ATP8B1encodes the FIC1-protein, which functions as an minophospholipid translocase. Because of secondary impaired biliary bile salt secretion, patients typically present with pruritus and low gamma-GT cholestasis in early childhood. FIC1 is also expressed in other tissues, such as pancreas and intestine, and extrahepatic manifestations may occur in FIC1-def patients. Ursodeoxycholic acid or surgical biliary diversion (SBD) techniques might be beneficial for some patients, yet many patients require liver transplantation(LTx) at some stage. We aim to better understand the natural course of FIC1-def and the efficacy of interventions. Therefore, we have set up an extensive international consortium, “NAPPED” (NAtural course and Prognosis of PFIC and Effect of biliary Diversion). Methods: We present retrospective follow up data on individual patients from 22 centers in Europe, North-America, Asia and Australia. All patients were either compound heterozygous or homozygous for disease associated mutations in the ATP8B1gene. We used time-dependent Cox regression for native liver survival (NLS), adjusted for gender and birth year, in patients that had undergone SBD (SBD+ve) or not (SBD-ve). Continuous variables are expressed as median [range]. Results: We included 46 FIC1-def patients (predominately males, 76%; P<0.001). Age at first visit was 0.5 [0-16.8] years. Use of ursodeoxycholic acid prior to first visit was 39%. Age at last follow up was 5.4 [0.25-27.8] years. Overall SBD rates at five/ten years of age were 37/43%, for males (36/45%) and females (50/50%, respectively; p=0.15). SBD rates in compound heterozygous and homozygous patients were 34/34% and 37/45%, respectively (p=0.29). Overall five/ten-year NLS was 74/46%. Five/ten-year NLS in males and females was 71/49% and 88/58%, respectively (p=0.87). NLS in compound heterozygous and homozygous patients was 78/33% and 72/52%, respectively (p=0.61). NLS did not differ significantly between SBD+ve patients and SBD-ve patients [HR=1.16; 95%CI(0.33-4.01); p=.82]. HCC was not encountered in any patient during follow-up, in contrast to observations in other cholestatic diseases. Mortality prior to LTx was 2%. The observed NLS at 18 years of age was 46%. Conclusion: Our large global cohort of this extremely rare condition allows to address genotype - phenotype relationships in FIC-1 deficiency and to study the natural course of diseases. Our data indicate that mortality is relatively low and that the vast majority of patients reaches adulthood, with native or transplanted liver, and thus becomes an important, relatively new patient entity for adult hepatology practice

Variceal Bleeds in Patients with Biliary Atresia

Introduction Portal hypertension often occurs in biliary atresia (BA). The subsequent development of esophageal varices and bleeding from these varices are a well-known complication. We aim to describe the incidence and severity of variceal bleeding in patients with BA. In addition, we describe the characteristics of patients who experienced variceal bleeds. Materials and Methods We included all infants treated for BA at our center between March 1987 and August 2015. Variceal bleeding was defined as hematemesis and/or melena with presence of varices at endoscopy. Findings at endoscopy and ultrasound, laboratory tests, clearance of jaundice, fibrosis-grade at Kasai portoenterostomy, and several varices prediction scores were documented. Routine endoscopies were not performed. Results In this study, 74 patients were included. During follow-up, 18 out of 74 patients (24%) developed variceal bleeding at an age of 9 months (range, 4-111). Twelve patients were listed for liver transplantation at the time of bleeding. Patients who did not clear their jaundice developed variceal bleeds more often and earlier in life. Bleeds were treated with sclerotherapy, banding, or octreotide. Four patients did not receive treatment. No bleeding-related mortality occurred. Conclusion One-fourth of the children diagnosed with BA experience variceal bleeds during follow-up. Most of these children are younger than 1 year and often already listed for transplantation. Major complications did not occur after variceal bleeding