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

Preterm Infants with Biliary Atresia : A Nationwide Cohort Analysis from the Netherlands

Objectives: Biliary atresia (BA) occurs in 0.54 of 10.000 of overall live births in the Netherlands. BA has an unfavorable prognosis: <40% of patients are cleared of jaundice after Kasai portoenterostomy (KPE), 4-year transplant-free survival rate is 46% and the 4-year survival rate is ∼75%. Little is known on difficulties in diagnosis and the outcome of BA in preterm infants. We aimed to analyze the incidence and outcome of BA in preterm infants in the Netherlands. Methods: Retrospective study including Dutch preterm infants treated for BA. Parameters included gestational age, congenital anomalies, age at KPE, days between first symptoms, and KPE and referral interval (first hospital to KPE). Outcome parameters were clearance of jaundice (COJ) and (transplant-free) survival. Data are presented as medians (ranges). Results: Included 28 preterm infants (13 boys/15 girls) between March 1988 and December 2015. The incidence of BA was 1.06 of 10.000 preterm live births. Gestational age was 34.8 (27.3-36.9) weeks. Congenital anomalies were present in 11 of 28 (39%) infants. Time between first symptoms and KPE was 57 (9-138) days. Referral interval was 28 (8-86) days. Age at KPE was 70 (35-145) days. COJ was achieved in 23% of cases. Four-year transplant-free survival rate was 21%. Four-year overall survival was 61%. Conclusions: BA has a higher incidence in the preterm population compared to the overall BA population. The outcome of BA in preterm infants is poor, regarding COJ and (transplant-free) survival. We speculate that timely recognition of BA-related signs and symptoms in preterm infants will improve prognosis

Preterm Infants with Biliary Atresia : A Nationwide Cohort Analysis from the Netherlands

Objectives: Biliary atresia (BA) occurs in 0.54 of 10.000 of overall live births in the Netherlands. BA has an unfavorable prognosis: <40% of patients are cleared of jaundice after Kasai portoenterostomy (KPE), 4-year transplant-free survival rate is 46% and the 4-year survival rate is ∼75%. Little is known on difficulties in diagnosis and the outcome of BA in preterm infants. We aimed to analyze the incidence and outcome of BA in preterm infants in the Netherlands. Methods: Retrospective study including Dutch preterm infants treated for BA. Parameters included gestational age, congenital anomalies, age at KPE, days between first symptoms, and KPE and referral interval (first hospital to KPE). Outcome parameters were clearance of jaundice (COJ) and (transplant-free) survival. Data are presented as medians (ranges). Results: Included 28 preterm infants (13 boys/15 girls) between March 1988 and December 2015. The incidence of BA was 1.06 of 10.000 preterm live births. Gestational age was 34.8 (27.3-36.9) weeks. Congenital anomalies were present in 11 of 28 (39%) infants. Time between first symptoms and KPE was 57 (9-138) days. Referral interval was 28 (8-86) days. Age at KPE was 70 (35-145) days. COJ was achieved in 23% of cases. Four-year transplant-free survival rate was 21%. Four-year overall survival was 61%. Conclusions: BA has a higher incidence in the preterm population compared to the overall BA population. The outcome of BA in preterm infants is poor, regarding COJ and (transplant-free) survival. We speculate that timely recognition of BA-related signs and symptoms in preterm infants will improve prognosis

Preterm Infants with Biliary Atresia : A Nationwide Cohort Analysis from the Netherlands

Objectives: Biliary atresia (BA) occurs in 0.54 of 10.000 of overall live births in the Netherlands. BA has an unfavorable prognosis: <40% of patients are cleared of jaundice after Kasai portoenterostomy (KPE), 4-year transplant-free survival rate is 46% and the 4-year survival rate is ∼75%. Little is known on difficulties in diagnosis and the outcome of BA in preterm infants. We aimed to analyze the incidence and outcome of BA in preterm infants in the Netherlands. Methods: Retrospective study including Dutch preterm infants treated for BA. Parameters included gestational age, congenital anomalies, age at KPE, days between first symptoms, and KPE and referral interval (first hospital to KPE). Outcome parameters were clearance of jaundice (COJ) and (transplant-free) survival. Data are presented as medians (ranges). Results: Included 28 preterm infants (13 boys/15 girls) between March 1988 and December 2015. The incidence of BA was 1.06 of 10.000 preterm live births. Gestational age was 34.8 (27.3-36.9) weeks. Congenital anomalies were present in 11 of 28 (39%) infants. Time between first symptoms and KPE was 57 (9-138) days. Referral interval was 28 (8-86) days. Age at KPE was 70 (35-145) days. COJ was achieved in 23% of cases. Four-year transplant-free survival rate was 21%. Four-year overall survival was 61%. Conclusions: BA has a higher incidence in the preterm population compared to the overall BA population. The outcome of BA in preterm infants is poor, regarding COJ and (transplant-free) survival. We speculate that timely recognition of BA-related signs and symptoms in preterm infants will improve prognosis

Preterm Infants with Biliary Atresia : A Nationwide Cohort Analysis from the Netherlands

Objectives: Biliary atresia (BA) occurs in 0.54 of 10.000 of overall live births in the Netherlands. BA has an unfavorable prognosis: <40% of patients are cleared of jaundice after Kasai portoenterostomy (KPE), 4-year transplant-free survival rate is 46% and the 4-year survival rate is ∼75%. Little is known on difficulties in diagnosis and the outcome of BA in preterm infants. We aimed to analyze the incidence and outcome of BA in preterm infants in the Netherlands. Methods: Retrospective study including Dutch preterm infants treated for BA. Parameters included gestational age, congenital anomalies, age at KPE, days between first symptoms, and KPE and referral interval (first hospital to KPE). Outcome parameters were clearance of jaundice (COJ) and (transplant-free) survival. Data are presented as medians (ranges). Results: Included 28 preterm infants (13 boys/15 girls) between March 1988 and December 2015. The incidence of BA was 1.06 of 10.000 preterm live births. Gestational age was 34.8 (27.3-36.9) weeks. Congenital anomalies were present in 11 of 28 (39%) infants. Time between first symptoms and KPE was 57 (9-138) days. Referral interval was 28 (8-86) days. Age at KPE was 70 (35-145) days. COJ was achieved in 23% of cases. Four-year transplant-free survival rate was 21%. Four-year overall survival was 61%. Conclusions: BA has a higher incidence in the preterm population compared to the overall BA population. The outcome of BA in preterm infants is poor, regarding COJ and (transplant-free) survival. We speculate that timely recognition of BA-related signs and symptoms in preterm infants will improve prognosis

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

Mutations in ATP8B1 can lead to familial intrahepatic cholestasis type 1 (FIC1) deficiency, or progressive familial intrahepatic cholestasis type 1 (PFIC1). 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 novel insights by using the largest genetically defined cohort of FIC1 deficiency patients to date. 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 PPTM), 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 18y. NLS was comparable between FIC1-A, FIC1-B, and FIC1-C (%NLS at age 10y: 67%, 41%, and 59%, respectively; P=0.12), despite FIC1-C undergoing SBD less often (%SBD at age 10y: 65%, 57%, and 45%, respectively; P=0.03). sBAs at presentation were negatively associated with NLS (NLS at age 10y; sBAs <194 µmol/L: 49% versus 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 <65μmol/L (P=0.05) tended to be associated with improved NLS. Conclusion: Less than half of FIC1 deficiency patients 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-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