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PurposeThe Retriever subunitVPS35Lis the third responsible gene for Ritscher-Schinzel syndrome (RSS) afterWASHC5andCCDC22. To date, only one pair of siblings have been reported and their condition was significantly more severe than typical RSS. This study aimed to understand the clinical spectrum and underlying molecular mechanism in VPS35L-associated RSS.MethodsWe report three new patients with biallelicVPS35Lvariants. Biochemical and cellular analyses were performed to elucidate disease aetiology.Results.In addition to typical features of RSS, we confirmed hypercholesterolaemia, hypogammaglobulinaemia and intestinal lymphangiectasia as novel complications of VPS35L-associated RSS. The latter two complications as well as proteinuria have not been reported in patients withCCDC22andWASHC5variants. One patient showed a severe phenotype and the other two were milder. Cells established from patients with the milder phenotypes showed relatively higher VPS35L protein expression. Cellular analysis found VPS35L ablation decreased the cell surface level of lipoprotein receptor-related protein 1 and low-density lipoprotein receptor, resulting in reduced low-density lipoprotein cellular uptake.ConclusionVPS35L-associated RSS is a distinct clinical entity with diverse phenotype and severity, with a possible molecular mechanism of hypercholesterolaemia. These findings provide new insight into the essential and distinctive role of Retriever in human development.

BackgroundVariants in the type IV collagen gene (COL4A1/2) cause early-onset cerebrovascular diseases. Most individuals are diagnosed postnatally, and the prenatal features of individuals with COL4A1/2 variants remain unclear.MethodsWe examined COL4A1/2 in 218 individuals with suspected COL4A1/2-related brain defects. Among those arising from COL4A1/2 variants, we focused on individuals showing prenatal abnormal ultrasound findings and validated their prenatal and postnatal clinical features in detail.ResultsPathogenic COL4A1/2 variants were detected in 56 individuals (n=56/218, 25.7%) showing porencephaly (n=29), schizencephaly (n=12) and others (n=15). Thirty-four variants occurred de novo (n=34/56, 60.7%). Foetal information was available in 47 of 56 individuals, 32 of whom (n=32/47, 68.1%) had one or more foetal abnormalities. The median gestational age at the detection of initial prenatal abnormal features was 31 weeks of gestation. Only 14 individuals had specific prenatal findings that were strongly suggestive of features associated with COL4A1/2 variants. Foetal ventriculomegaly was the most common initial feature (n=20/32, 62.5%). Posterior fossa abnormalities, including Dandy-Walker malformation, were observed prenatally in four individuals. Regarding extrabrain features, foetal growth restriction was present in 16 individuals, including eight individuals with comorbid ventriculomegaly.ConclusionsPrenatal observation of ventriculomegaly with comorbid foetal growth restriction should prompt a thorough ultrasound examination and COL4A1/2 gene testing should be considered when pathogenic variants are strongly suspected.

BackgroundIn this study, we aimed to identify the gene abnormality responsible for pathogenicity in an individual with an undiagnosed neurodevelopmental disorder with megalencephaly, ventriculomegaly, hypoplastic corpus callosum, intellectual disability, polydactyly and neuroblastoma. We then explored the underlying molecular mechanism.MethodsTrio-based, whole-exome sequencing was performed to identify disease-causing gene mutation. Biochemical and cell biological analyses were carried out to elucidate the pathophysiological significance of the identified gene mutation.ResultsWe identified a heterozygous missense mutation (c.173C>T; p.Thr58Met) in theMYCNgene, at the Thr58 phosphorylation site essential for ubiquitination and subsequent MYCN degradation. The mutant MYCN (MYCN-T58M) was non-phosphorylatable at Thr58 and subsequently accumulated in cells and appeared to induce CCND1 and CCND2 expression in neuronal progenitor and stem cells in vitro. Overexpression of Mycn mimicking the p.Thr58Met mutation also promoted neuronal cell proliferation, and affected neuronal cell migration during corticogenesis in mouse embryos.ConclusionsWe identified a de novo c.173C>T mutation inMYCNwhich leads to stabilisation and accumulation of the MYCN protein, leading to prolonged CCND1 and CCND2 expression. This may promote neurogenesis in the developing cerebral cortex, leading to megalencephaly. While loss-of-function mutations inMYCNare known to cause Feingold syndrome, this is the first report of a germline gain-of-function mutation inMYCNidentified in a patient with a novel megalencephaly syndrome similar to, but distinct from, CCND2-related megalencephaly-polymicrogyria-polydactyly-hydrocephalus syndrome. The data obtained here provide new insight into the critical role of MYCN in brain development, as well as the consequences of MYCN defects.

Background Heterozygous mutations in CTCF have been reported in patients with distinct clinical features including intellectual disability. However, the precise pathomechanism underlying the phenotype remains to be uncovered, partly because of the diverse function of CTCF. Here we describe extensive clinical and genetic investigation for two patients with a microdeletion encompassing CTCF . Methods We performed genetic examination including comprehensive investigation of X chromosome inactivation and DNA methylation profiling at imprinted loci and genome-wide. Results Two patients showed comparable clinical features to those in a previous report, indicating that haploinsufficiency of CTCF was the major determinant of the microdeletion syndrome. Despite the haploinsufficiency of CTCF, X chromosome inactivation was normal. DNA methylation at imprinted loci was normal, but hypermethylation at CTCF binding sites was demonstrated, of which PRKCZ and FGFR2 were identified as candidate genes. Conclusions This study confirms that haploinsufficiency of CTCF causes distinct clinical features, and that a microdeletion encompassing CTCF could cause a recognisable CTCF deletion syndrome. Perturbed DNA methylation at CTCF binding sites, not at imprinted loci, may underlie the pathomechanism of the syndrome.

PurposeEffects of fetal, perinatal and childhood environment on the health of children at birth and during later life have become a topic of concern. The Aichi regional sub-cohort of the Japan Environment and Children’s Study (JECS-A) is an ongoing birth cohort of pregnant women and their children which has been used to provide unique data, as adjunct studies of JECS, on multifaceted potential factors affecting children’s health.ParticipantsThe JECS-A is part of the JECS which follows a total of 100 000 pairs of children and their mothers (fathers’ participation is optional) across 15 regions in Japan. In JECS-A, of the 8134 pregnant women living in Ichinomiya City and Nagoya City, Japan, a total of 5721 pregnant women and their 5554 children were included. Sociodemographic and psychological data as well as biological specimens were collected from the pregnant women and their spouses (if available) in the cohort during their pregnancy. Information on children included in the JECS-A was collected from their mothers and includes demographic, behavioural, childcare, psychological and psychiatric data. Urine extracted from disposable diapers and anthropometric data were also obtained from the children.Findings to dateA similar distribution trend for age at delivery was confirmed between the pregnant women enrolled in the JECS-A and the national statistics of the relevant areas. However, differences in education level and household income were observed. A total of 5502 children remained in the cohort at 18 months after delivery. Compared with the national statistics, the basic demographics of the children in the cohort represented the population in the study areas.Future plansThe enrolled children in the JECS-A will be followed until the age of 13 years. The studies that come from JECS-A will complement JECS and bring novel results with a high level of generalisability.

Background : Myoclonic epilepsy with ragged-red fibres (MERRF) and mitochondrial encephalopathy, lactic acidosis and stroke-like episodes (MELAS) are established phenotypes of mitochondrial encephalomyopathy. The m.8356T>C transition in the mitochondrial tRNALys gene is a pathogenic mutations of MERRF. The m.3243A>G transition in the mitochondrial tRNALeu gene is detected in most MELAS patients. Although previous analyses of double mutations in mitochondrial DNA (mtDNA) were useful for discussing their nature, many unsolved questions remain. Objective : To describe the clinical and genetic features of a family with the above mtDNA double-point mutations and discuss the role of double mtDNA mutations in diverse clinical features in the family. Patients and methods : The proband was a 23-year-old woman with MERRF harbouring m.8356T>C and m.3243A>G transitions in mitochondrial tRNA genes. We assessed clinical aspects of her and those of her three relatives and performed mutation analyses on their mtDNA. Results : Phenotypes of the four patients were MERRF, MERRF/MELAS overlap syndrome and asymptomatic carrier. We hypothesise that the course of the phenotype of this family begins with MERRF and is followed by MELAS. This double mutation was heteroplasmic in blood of all four patients but with different rates in each patient, while m.8356T>C appeared homoplasmic and m.3243A>G was heteroplasmic in muscle of the two examined cases. No other mutations were detected in the total mtDNA sequence in this family. Conclusions : This is the first reported case of a double-point mutation in mtDNA, both of which were heteroplasmic and pathogenic for the established phenotypes.

Background and aims Rates of traditional medical autopsy are low in Japan. In particular, obtaining consent for autopsy of children from parents is difficult. Although postmortem imaging of adults has been well studied, this is not the case in children. Few studies have investigated the accuracy of postmortem imaging in diagnosing the causes of neonatal deaths. We aimed to identify the accuracy of postmortem computed tomography (CT), and compared postmortem CT findings to clinical diagnosis and autopsy in the neonatal intensive care unit (NICU). Methods Twenty-five patients died in our NICU from 2010 to 2012. Consent for autopsy was obtained for 10 cases (40%) and consent for postmortem imaging was obtained for 19 (76%). Both postmortem imaging and autopsy were able to be performed for 10 cases (40%). Results The concordance rate between cause of death from postmortem CT and that from clinical diagnosis was 74% (14/19), while the rate between cause of death from postmortem CT and that from autopsy was 70% (7/10). Moreover, postmortem CT uncovered unrecognised diagnoses such as pericardial emphysema that remained undetected from the clinical course or autopsy. Conclusions Postmortem imaging is reliable and valid in NICU settings, and the combination of postmortem imaging and autopsy could improve the accuracy of determining causes of neonatal deaths.

Background and aims Neonatal cholestasis is caused by either biliary atresia or intrahepatic cholestasis. Congenital combined pituitary hormone deficiency (CPHD) is a rare disease and a recognised cause of intrahepatic cholestasis. It is important to differentiate cholestasis due to this entity from cholestasis due to biliary atresia, since both diseases can cause jaundice at about 1 month of age. However, doing so in a timely fashion remains a diagnostic dilemma. This retrospective study was performed to clarify differences between cholestasis due to congenital CPHD and cholestasis due to biliary atresia. Methods From 2004 to 2010, 4 infants (2 boys and 2 girls) with cholestasis due to congenital CPHD were admitted to Nagoya City University Hospital. Head magnetic resonance imaging of the 4 infants revealed an invisible pituitary stalk; 3 of these 4 infants had an ectopic posterior pituitary. Liver biopsy was performed in 3 of the 4 infants, and histological findings included giant cell hepatitis. Findings from these 4 infants were then compared with those from55 infants treated in our hospital for cholestasis due to biliary atresia. Results The results showed a significant difference in mean gamma-glutamyl transpeptidase levels between the two groups of infants (115.0 IU/l vs. 553.0 IU/l, respectively). Conclusions The gamma-glutamyl transpeptidase level was found to be useful for distinguishing congenital CPHD from biliary atresia as the cause of cholestasis. The diagnosis of hypopituitarism should always be considered in infants with unexplained neonatal hepatitis.