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We report the clinical and genetic features of a Han Chinese boy who presented with disease suspect for Alagille syndrome (ALGS). Multiple genetic analyses (panel sequencing, multiplex-ligation-dependent probe amplification, and whole genome sequencing) failed to uncover a causative variant. Optical genomic mapping detected a reciprocal translocation between chromosomes 4 and 20, interrupting JAG1. Long-range polymerase chain reaction and targeted sequencing identified the exact breakpoints. Sanger sequencing and reanalysis of genome sequencing raw data further confirmed the result. This translocation is expected to generate aberrant JAG1 transcripts that lead to complete loss of JAG1 expression. This is the first t(4;20)(q22.1;p12.2) balanced translocation detected by optical genomic mapping and characterized at base-pair resolution in ALGS. Our approach permitted precise diagnosis and genetic counseling.

Altres ajuts: Supported by grants from the Nederlandse vereniging voor Gastroenterologie (to S. I. J.) and the Natural Science Foundation of China, Nos. 81873543 and 81570468 (to J. S. W.). Progressive familial intrahepatic cholestasis (PFIC) 6 has been associated with missense but not biallelic nonsense or frameshift mutations in MYO5B, encoding the motor protein myosin Vb (myoVb). This genotype-phenotype correlation and the mechanism through which MYO5B mutations give rise to PFIC are not understood. The aim of this study was to determine whether the loss of myoVb or expression of patient-specific myoVb mutants can be causally related to defects in canalicular protein localization and, if so, through which mechanism. We demonstrate that the cholestasis-associated substitution of the proline at amino acid position 600 in the myoVb protein to a leucine (P660L) caused the intracellular accumulation of bile canalicular proteins in vesicular compartments. Remarkably, the knockout of MYO5B in vitro and in vivo produced no canalicular localization defects. In contrast, the expression of myoVb mutants consisting of only the tail domain phenocopied the effects of the Myo5b-P660L mutation. Using additional myoVb and rab11a mutants, we demonstrate that motor domain-deficient myoVb inhibited the formation of specialized apical recycling endosomes and that its disrupting effect on the localization of canalicular proteins was dependent on its interaction with active rab11a and occurred at the trans -Golgi Network/recycling endosome interface. Our results reveal a mechanism through which MYO5B motor domain mutations can cause the mislocalization of canalicular proteins in hepatocytes which, unexpectedly, does not involve myoVb loss-of-function but, as we propose, a rab11a-mediated gain-of-toxic function. The results explain why biallelic MYO5B mutations that affect the motor domain but not those that eliminate myoVb expression are associated with PFIC6.

Early diagnosis of Niemann-Pick disease type C (NP-C) in neonatal cholestasis is still challenging because splenomegaly is non-specific and oxysterol profiling studies also have a relatively low specificity. This study explores a method for identifying infants with a high clinical suspicion of NP-C in neonatal cholestasis. We reviewed the clinical findings of 9 neonatal cholestatic infants with NP-C genetically diagnosed between January 2015 and December 2020. Seven underwent liver biopsy at ages ranging from 35 to 112 d. Foam cells were only detected in 2 (28.6%, 2/7) liver tissues obtained beyond 3 months of age. However, vacuolated Kupffer cells were detected in all 7 liver tissues. Their significance was explored by using 168 neonatal cholestatic infants, who underwent genetic tests and liver biopsy between January 2018 and December 2020. Of them, 26 detected vacuolated Kupffer cells. Six (23.1%, 6/26) were diagnosed as NP-C, comparing to none of the 142 neonatal cholestatic infants without vacuolated Kupffer cells (χ2 = 33.983, p < 0.001). The ratio of positive diagnosis of NP-C was 31.6% (6/19) in neonatal cholestatic infants with both vacuolated Kupffer cells and splenomegaly. Therefore, we conclude that the presence of vacuolated Kupffer cells can raise a high clinical suspicion of NP-C in neonatal cholestatic infants, especially in those with splenomegaly.

Additional file 1. Renal images in additional patients.

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 mu mol/L: 49% vs. sBAs >= 194 mu mol/L: 15%; P = 0.03). SBD decreased sBAs (230 [125-282] to 74 [11-177] mu mol/L; P = 0.005). SBD (HR 0.55, 95% CI 0.28-1.03, P = 0.06) and post-SBD sBA concentrations < 65 mu mol/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.

Additional file 2. Table S1. Pathogenicity prediction of novel variants in HSD3B7; Table S2. Previously reported variants in HSD3B7; Table S3. Serum liver biochemistries at first referral and at last follow-up; Table S4. Correlation of genotype and phenotype in patients with HSD3B7 deficiency.

Background: Alagille syndrome (ALGS) is a multisystem disorder, typically presenting with neonatal cholestasis. Prior cohort studies in ALGS largely come from tertiary center liver centers and therefore select for the most severely affected cholestatic patients. As a result, the full spectrum of ALGS liver involvement remains unclear. Furthermore, a comprehensive assessment of extrahepatic manifestations in a large cohort of patients is missing. In 2017, the Global ALagille Alliance (GALA) Study Group was established to overcome these limitations. Methods: This is a retrospective multicentre study in children and young adults with a clinically and/or genetically confirmed diagnosis of ALGS, born between January 1997-May 2019. Histopathological findings before and after 6 months were compared using chi-square test. Native liver survival (NLS) in patients presenting with neonatal cholestasis and overall survival were estimated using cox regression analysis. Results: 731 ALGS (41% female) subjects from 32 centres were included (median follow-up 4.75 yrs, IQR 2.0-10.2). Among the 76% (n=554/731) genetically-confirmed patients, 95% had a JAG1 mutation and 4% a NOTCH2mutation (70% de novo). Presence of any cardiac anomaly and characteristic facies were the most common clinical manifestations, 87% (each), followed by posterior embryotoxon, 45%, butterfly vertebrae, 43% and renal anomalies, 38%. Available MRI and CT reports (mostly performed for screening) revealed cerebral and intra-abdominal vascular anomalies in 36% (n=57/159) and 26% (n=27/105) of subjects, respectively. 79% of ALGS subjects presented with neonatal cholestasis. 299 initial liver biopsy reports were reviewed (Table 1) and revealed an increasing frequency of bile duct paucity with age and of note, bile duct plugs in 6% of biopsies

Mutation analysis of the GPD1 gene in the proband and her parents. The patient was a homozygote and her parents were heterozygous for the mutation. (DOCX 853 kb)

Reported genes associated with acute liver failure. (DOCX 16 kb)

Details of RALF in patient 3. ALT, alanine aminotransferase; AST, aspartate aminotransferase; GGT, gamma-glutamyl transpeptidase; INR, international normalized ratio; TB, total bilirubin; TBA, total bile acids. (DOCX 15 kb)

Variant filtering strategy for patients 1â 5. A. Filtering procedure for suspected pathogenic genes for a single sample. B. Filtering procedure for candidate gene list. ALF, acute liver failure. (DOCX 81 kb)

Sequencing statistics for patients 1â 5. (DOCX 14 kb)

Ages during episodes of ALF and liver crises. P, patient. ALF, acute liver failure. N1, episodes of ALF. N2, episodes of acute liver crisis. The age of last following up for patients 1â 3 is 6y 11Â m, 4y 8Â m, and 2y4m, respectively. With the increasing age, the episodes of ALF and RALF were not decreased (DOCX 14 kb)

Candidate genes for patients 1â 5. (DOCX 14 kb)

Specific primers for NBAS exons 8, 22, 31, 43, and 50. (DOCX 14 kb)

Two tetrapus molecules,1a and 1b, were synthesized. They each possess fluorinated tentacles with anionic termini, i.e., CH2O(CH2)3(CF2)2O(CF2)2SO3−,Na+ for 1a and CH2O(CH2)3(CF2)4O(CF2)2SO3−,Na+ for 1b. Cationic and anionic naphthalene fluorescence probes with CH2CH2O(CH2)10-chains (Fp+ and FP−) were used to study host-guest interactions between partners of the following pairs, i.e., 1a and FP+, 1a and FP−, 1b and FP+, 1b and FP−. Our results demonstrate that electrostatic attraction is a powerful factor in facilitating the host-guest interactions between the tetrapus and the long-chain probes.

The effects of magnetic saturation on the steady-state synchronous reactance have been fully studied. By using the 2D P.E.M., the steady-state saturated reactances are determined directly from flux linkages. The variation of direct synchronous reactance Xd with saturation under zero-power-factor (lag or lead) condition, purely quadrature magnetising, and rated load condition are presented. Also the saturated values of quadrature synchronous reactances Xq under these conditions, as well as the coupling reactances Xdq end Xqd between d- and q- axes are presented.

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