Background Intrahepatic cholestasis of pregnancy is associated with adverse perinatal outcomes, but the association with the concentration of specific biochemical markers is unclear. We aimed to quantify the adverse perinatal effects of intrahepatic cholestasis of pregnancy in women with increased serum bile acid concentrations and determine whether elevated bile acid concentrations were associated with the risk of stillbirth and preterm birth. Methods We did a systematic review by searching PubMed, Web of Science, and Embase databases for studies published from database inception to June 1, 2018, reporting perinatal outcomes for women with intrahepatic cholestasis of pregnancy when serum bile acid concentrations were available. Inclusion criteria were studies defining intrahepatic cholestasis of pregnancy based upon pruritus and elevated serum bile acid concentrations, with or without raised liver aminotransferase concentrations. Eligible studies were case-control, cohort, and populationbased studies, and randomised controlled trials, with at least 30 participants, and that reported bile acid concentrations and perinatal outcomes. Studies at potential higher risk of reporter bias were excluded, including case reports, studies not comprising cohorts, or successive cases seen in a unit; we also excluded studies with high risk of bias from groups selected (eg, a subgroup of babies with poor outcomes were explicitly excluded), conference abstracts, and Letters to the Editor without clear peer review. We also included unpublished data from two UK hospitals. We did a random effects meta-analysis to determine risk of adverse perinatal outcomes. Aggregate data for maternal and perinatal outcomes were extracted from case-control studies, and individual patient data (IPD) were requested from study authors for all types of study (as no control group was required for the IPD analysis) to assess associations between biochemical markers and adverse outcomes using logistic and stepwise logistic regression. This study is registered with PROSPERO, number CRD42017069134. Findings We assessed 109 full-text articles, of which 23 studies were eligible for the aggregate data meta-analysis (5557 intrahepatic cholestasis of pregnancy cases and 165 136 controls), and 27 provided IPD (5269 intrahepatic cholestasis of pregnancy cases). Stillbirth occurred in 45 (0•91%) of 4936 intrahepatic cholestasis of pregnancy cases and 519 (0•32%) of 163 947 control pregnancies (odds ratio [OR] 1•46 [95% CI 0•73-2•89]; I²=59•8%). In singleton pregnancies, stillbirth was associated with maximum total bile acid concentration (area under the receiver operating characteristic curve [ROC AUC]) 0•83 [95% CI 0•74-0•92]), but not alanine aminotransferase (ROC AUC 0•46 [0•35-0•57]). For singleton pregnancies, the prevalence of stillbirth was three (0•13%; 95% CI 0•02-0•38) of 2310 intrahepatic cholestasis of pregnancy cases in women with serum total bile acids of less than 40 µmol/L versus four (0•28%; 0•08-0•72) of 1412 cases with total bile acids of 40-99 µ...

Summary Accurate identification of sparse heterozygous single-nucleotide variants (SNVs) is a critical challenge for identifying the causative mutations in mouse genetic screens, human genetic diseases and cancer. When seeking to identify causal DNA variants that occur at such low rates, they are overwhelmed by false-positive calls that arise from a range of technical and biological sources. We describe a strategy using whole-exome capture, massively parallel DNA sequencing and computational analysis, which identifies with a low false-positive rate the majority of heterozygous and homozygous SNVs arising de novo with a frequency of one nucleotide substitution per megabase in progeny of N -ethyl- N -nitrosourea (ENU)-mutated C57BL/6j mice. We found that by applying a strategy of filtering raw SNV calls against known and platform-specific variants we could call true SNVs with a false-positive rate of 19.4 per cent and an estimated false-negative rate of 21.3 per cent. These error rates are small enough to enable calling a causative mutation from both homozygous and heterozygous candidate mutation lists with little or no further experimental validation. The efficacy of this approach is demonstrated by identifying the causative mutation in the Ptprc gene in a lymphocyte-deficient strain and in 11 other strains with immune disorders or obesity, without the need for meiotic mapping. Exome sequencing of first-generation mutant mice revealed hundreds of unphenotyped protein-changing mutations, 52 per cent of which are predicted to be deleterious, which now become available for breeding and experimental analysis. We show that exome sequencing data alone are sufficient to identify induced mutations. This approach transforms genetic screens in mice, establishes a general strategy for analysing rare DNA variants and opens up a large new source for experimental models of human disease.

Congenital myopathies define a heterogeneous group of neuromuscular diseases with neonatal or childhood hypotonia and muscle weakness. The genetic cause is still unknown in many patients, precluding genetic counselling and better understanding of the physiopathology. To identify novel genetic causes of congenital myopathies, exome sequencing was performed in three consanguineous families. We identified two homozygous frameshift mutations and a homozygous nonsense mutation in the mitogen-activated protein triple kinase ZAK. In total, six affected patients carry these mutations. Reverse transcription polymerase chain reaction and transcriptome analyses suggested nonsense mRNA decay as a main impact of mutations. The patients demonstrated a generalized slowly progressive muscle weakness accompanied by decreased vital capacities. A combination of proximal contractures with distal joint hyperlaxity is a distinct feature in one family. The low endurance and compound muscle action potential amplitude were strongly ameliorated on treatment with anticholinesterase inhibitor in another patient. Common histopathological features encompassed fibre size variation, predominance of type 1 fibre and centralized nuclei. A peculiar subsarcolemmal accumulation of mitochondria pointing towards the centre of the fibre was a novel histological hallmark in one family. These findings will improve the molecular diagnosis of congenital myopathies and implicate the mitogen-activated protein kinase (MAPK) signalling as a novel pathway altered in these rare myopathies.

Mutations in GALC cause Krabbe disease. This autosomal recessive leukodystrophy generally presents in early infancy as a severe disorder, but sometimes manifests as a milder adult-onset disease with spastic paraplegia as the main symptom. We recruited a family with five affected individuals presenting with adult-onset predominant cerebellar ataxia with mild spasticity. Whole exome sequencing (WES) revealed one novel and one previously reported compound heterozygous variants in GALC. Magnetic resonance imaging (MRI) confirmed the presence of typical Krabbe features. Our findings expand the phenotypic spectrum of adult-onset Krabbe disease and demonstrate the usefulness of combining WES and pattern-specific MRI for the diagnosis of neurodegenerative diseases.