Prenatal maternal depressive symptoms and infant DNA methylation: a longitudinal epigenome-wide study.

Background: Prenatal maternal stress increases the risk of offspring developmental and psychological difficulties. The biological mechanisms behind these associations are mostly unknown. One explanation suggests that exposure of the fetus to maternal stress may influence DNA methylation. However, this hypothesis is largely based on animal studies, and human studies of candidate genes from single timepoints. Aim: The aim of this study was to investigate if prenatal maternal stress, in the form of maternal depressive symptoms, was associated with variation in genome-wide DNA methylation at two timepoints. Methods: One-hundred and eighty-four mother-child dyads were selected from a population of pregnant women in the Little-in-Norway study. The Edinburgh Postnatal Depression Scale (EPDS) measured maternal depressive symptoms. It was completed by the pregnant mothers between weeks 17 and 32 of gestation. DNA was obtained from infant saliva cells at two timepoints (age 6 weeks and 12 months). DNA methylation was measured in 274 samples from 6 weeks (n = 146) and 12 months (n = 128) using the Illumina Infinium HumanMethylation 450 BeadChip. Linear regression analyses of prenatal maternal depressive symptoms and infant methylation were performed at 6 weeks and 12 months separately, and for both timepoints together using a mixed model. Results: The analyses revealed no significant genome-wide association between maternal depressive symptoms and infant DNA methylation in the separate analyses and for both timepoints together. Conclusions: This sample of pregnant women and their infants living in Norway did not reveal associations between maternal depressive symptoms and infant DNA methylation.

BRCA mutation carrier detection. A model-based cost-effectiveness analysis comparing the traditional family history approach and the testing of all patients with breast cancer.

BACKGROUND: Identification of BRCA mutation carriers among patients with breast cancer (BC) involves costs and gains. Testing has been performed according to international guidelines, focusing on family history (FH) of breast and/or ovarian cancer. An alternative is testing all patients with BC employing sequencing of the BRCA genes and Multiplex Ligation Probe Amplification (MLPA). PATIENTS AND METHODS: A model-based cost-effectiveness analysis, employing data from Oslo University Hospital, Ullevål (OUH-U) and a decision tree, was done. The societal and the healthcare perspectives were focused and a lifetime perspective employed. The comparators were the traditional FH approach used as standard of care at OUH-U in 2013 and the intervention (testing all patients with BC) performed in 2014 and 2015 at the same hospital. During the latter period, 535 patients with BC were offered BRCA testing with sequencing and MLPA. National 2014 data on mortality rates and costs were implemented, a 3% discount rate used and the costing year was 2015. The incremental cost-effectiveness ratio was calculated in euros (€) per life-year gained (LYG). RESULTS: The net healthcare cost (healthcare perspective) was €40 503/LYG. Including all resource use (societal perspective), the cost was €5669/LYG. The univariate sensitivity analysis documented the unit cost of the BRCA test and the number of LYGs the prominent parameters affecting the result.Diagnostic BRCA testing of all patients with BC was superior to the FH approach and cost-effective within the frequently used thresholds (healthcare perspective) in Norway (€60 000-€80 000/LYG).

Current guidelines for BRCA testing of breast cancer patients are insufficient to detect all mutation carriers.

BACKGROUND: Identification of BRCA mutations in breast cancer (BC) patients influences treatment and survival and may be of importance for their relatives. Testing is often restricted to women fulfilling high-risk criteria. However, there is limited knowledge of the sensitivity of such a strategy, and of the clinical aspects of BC caused by BRCA mutations in less selected BC cohorts. The aim of this report was to address these issues by evaluating the results of BRCA testing of BC patients in South-Eastern Norway. METHODS: 1371 newly diagnosed BC patients were tested with sequencing and Multi Ligation Probe Amplification (MLPA). Prevalence of mutations was calculated, and BC characteristics among carriers and non-carriers compared. Sensitivity and specificity of common guidelines for BRCA testing to identify carriers was analyzed. Number of identified female mutation positive relatives was evaluated. RESULTS: A pathogenic BRCA mutation was identified in 3.1%. Carriers differed from non-carriers in terms of age at diagnosis, family history, grade, ER/PR-status, triple negativity (TNBC) and Ki67, but not in HER2 and TNM status. One mutation positive female relative was identified per mutation positive BC patient. Using age of onset below 40 or TNBC as criteria for testing identified 32-34% of carriers. Common guidelines for testing identified 45-90%, and testing all below 60 years identified 90%. Thirty-seven percent of carriers had a family history of cancer that would have qualified for predictive BRCA testing. A Variant of Uncertain Significance (VUS) was identified in 4.9%. CONCLUSIONS: Mutation positive BC patients differed as a group from mutation negative. However, the commonly used guidelines for testing were insufficient to detect all mutation carriers in the BC cohort. Thirty-seven percent had a family history of cancer that would have qualified for predictive testing before they were diagnosed with BC. Based on our combined observations, we suggest it is time to discuss whether all BC patients should be offered BRCA testing, both to optimize treatment and improve survival for these women, but also to enable identification of healthy mutation carriers within their families. Health services need to be aware of referral possibility for healthy women with cancer in their family.

Pathogenic variants in KCTD7 perturb neuronal K+ fluxes and glutamine transport.

Progressive myoclonus epilepsy is a heterogeneous group of disorders characterized by myoclonic and tonic-clonic seizures, ataxia and cognitive decline. We here present two affected brothers. At 9 months of age the elder brother developed ataxia and myoclonic jerks. In his second year he lost the ability to walk and talk, and he developed drug-resistant progressive myoclonus epilepsy. The cerebrospinal fluid level of glutamate was decreased while glutamine was increased. His younger brother manifested similar symptoms from 6 months of age. By exome sequencing of the proband we identified a novel homozygous frameshift variant in the potassium channel tetramerization domain 7 (KCTD7) gene (NM_153033.1:c.696delT: p.F232fs), which results in a truncated protein. The identified F232fs variant is inherited in an autosomal recessive manner, and the healthy consanguineous parents carry the variant in a heterozygous state. Bioinformatic analyses and structure modelling showed that KCTD7 is a highly conserved protein, structurally similar to KCTD5 and several voltage-gated potassium channels, and that it may form homo- or heteromultimers. By heterologous expression in Xenopus laevis oocytes, we demonstrate that wild-type KCTD7 hyperpolarizes cells in a K+ dependent manner and regulates activity of the neuronal glutamine transporter SAT2 (Slc38a2), while the F232fs variant impairs K+ fluxes and obliterates SAT2-dependent glutamine transport. Characterization of four additional disease-causing variants (R94W, R184C, N273I, Y276C) bolster these results and reveal the molecular mechanisms involved in the pathophysiology of KCTD7-related progressive myoclonus epilepsy. Thus, our data demonstrate that KCTD7 has an impact on K+ fluxes, neurotransmitter synthesis and neuronal function, and that malfunction of the encoded protein may lead to progressive myoclonus epilepsy.

Intra-individual changes in DNA methylation not mediated by cell-type composition are correlated with aging during childhood.

BACKGROUND: Several studies have reported age-associated changes in DNA methylation in the first few years of life and in adult populations, but the extent of such changes during childhood is less well studied. The goals of this study were to investigate to what degree intra-individual changes in DNA methylation are associated with aging during childhood and dissect the methylation changes directly associated with aging from the effect mediated through variation in cell-type composition (CTC). RESULTS: We performed reduced representation bisulfite sequencing (RRBS) in peripheral whole-blood samples collected at 2, 10, and 16 years of age. We identified age-associated longitudinal changes in DNA methylation at 346 CpGs in 178 genes. Analyses separating the effect mediated by CTC variability across age identified 26 CpGs located in 12 genes that associated directly with age. Hence, the CTC changes across age appear to act as a mediator of the observed DNA methylation associated with age. The results were replicated using EpiTYPER in a second sample set selected from the same cohort. Gene ontology analyses revealed enrichment of transcriptional regulation and developmental processes. Further, comparisons of the mean DNA methylation differences between the time points reveal greater differences between 2 to 10 years and 10 to 16 years, suggesting that the identified age-associated DNA methylation patterns manifests in early childhood. CONCLUSIONS: This study reveals insights into the epigenetic dynamics associated with aging early in life. Such information could ultimately provide clues and point towards molecular pathways that are susceptible to aging-related disease-associated epigenetic dysregulation.

Strømme Syndrome Is a Ciliary Disorder Caused by Mutations in CENPF.

Strømme syndrome was first described by Strømme et al. (1993) in siblings presenting with "apple peel" type intestinal atresia, ocular anomalies and microcephaly. The etiology remains unknown to date. We describe the long-term clinical follow-up data for the original pair of siblings as well as two previously unreported siblings with a severe phenotype overlapping that of the Strømme syndrome including fetal autopsy results. Using family-based whole-exome sequencing, we identified truncating mutations in the centrosome gene CENPF in the two nonconsanguineous Caucasian sibling pairs. Compound heterozygous inheritance was confirmed in both families. Recently, mutations in this gene were shown to cause a fetal lethal phenotype, the phenotype and functional data being compatible with a human ciliopathy [Waters et al., 2015]. We show for the first time that Strømme syndrome is an autosomal-recessive disease caused by mutations in CENPF that can result in a wide phenotypic spectrum.

A conserved eEF2 coding variant in SCA26 leads to loss of translational fidelity and increased susceptibility to proteostatic insult.

The autosomal dominant spinocerebellar ataxias (SCAs) are a genetically heterogeneous group of disorders exhibiting cerebellar atrophy and Purkinje cell degeneration whose subtypes arise from 31 distinct genetic loci. Our group previously published the locus for SCA26 on chromosome 19p13.3. In this study, we performed targeted deep sequencing of the critical interval in order to identify candidate causative variants in individuals from the SCA26 family. We identified a single variant that co-segregates with the disease phenotype that produces a single amino acid substitution in eukaryotic elongation factor 2. This substitution, P596H, sits in a domain critical for maintaining reading frame during translation. The yeast equivalent, P580H EF2, demonstrated impaired translocation, detected as an increased rate of -1 programmed ribosomal frameshift read-through in a dual-luciferase assay for observing translational recoding. This substitution also results in a greater susceptibility to proteostatic disruption, as evidenced by a more robust activation of a reporter gene driven by unfolded protein response activation upon challenge with dithiothreitol or heat shock in our yeast model system. Our results present a compelling candidate mutation and mechanism for the pathogenesis of SCA26 and further support the role of proteostatic disruption in neurodegenerative diseases.

Autosomal dominant pericentral retinal dystrophy caused by a novel missense mutation in the TOPORS gene.

PURPOSE: This study aimed to identify the genetic cause of autosomal dominant pericentral retinal dystrophy (adPRD) in a large Norwegian family with 35 affected members. METHODS: The family was characterized by clinical ophthalmological examination along with fundus photography, dark adaptometry and electroretinography. We performed a genome-wide linkage analysis followed by sequencing of a candidate gene to identify the mutation causing the disease. RESULTS: The ophthalmological examinations revealed an atypical form of retinitis pigmentosa (RP), which we prefer to call adPRD. Compared with classical RP, this phenotype has a favourable prognosis. Linkage analysis showed a linkage peak covering the most recently reported adRP gene TOPORS. This gene was sequenced in 19 family members and a novel missense mutation, c.1205a>c, resulting in an amino acid substitution p.Q402P, was detected in all affected members. The mutation showed complete co-segregation with the disease in this family, with a LOD score of 7.3. It is located in a highly conserved region and alignment with the appropriate DNA sequence from other species shows complete conservation of this amino acid. The mutation was not detected in 207 healthy, unrelated controls of Norwegian origin. CONCLUSIONS: We present a novel mutation in the TOPORS gene co-segregating with a distinct phenotype of adPRD in a large Norwegian family.

SCN1A mutation screening in adult patients with Lennox-Gastaut syndrome features.

Mutations in the SCN1A gene have been identified in a variety of epilepsy phenotypes, from severe encephalopathies such as Dravet syndrome to milder familial forms such as generalized epilepsy with febrile seizures plus. In a previous study, an SCN1A mutation was also identified in a patient with Lennox-Gastaut syndrome (LGS), and the aim of our study was to investigate the importance of mutations in the SCN1A gene in Norwegian patients with clinical features of LGS. We screened 22 adult patients for SCN1A mutations by direct sequencing of DNA and for micro-rearrangements with multiplex ligation-dependent probe amplification. In one patient a mutation was found, which demonstrates a clinical overlap between LGS and Dravet syndrome. This finding emphasizes the significance of SCN1A mutations also in epileptic disorders with features of LGS, particularly in the myoclonic variant of the disorder.