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The aim of the study was to analyze the genetic basis of a various range of neurodegenerative disorders manifesting by movement disorders (MD) using next generation sequencing (NGS) clinical exome panel. The study included a total number of 42 cases, 36 unrelated and 3 sibling pairs patients diagnosed with movement disorders, all negative after targeted genetic testing available at Neurology clinic, UCCS, Belgrade, Serbia. In a selection of respondents, preference was given to family cases with the early presentation, patients with a positive family history, or complex MD phenotype. Sequencing of a Clinical exome (CE) panel for 4813 genes with known associated clinical phenotypes was performed on an Illumina MiSeq NGS platform according to the manufacturer?s instructions. Sequence variants were analyzed by Illumina?s Variant Studio v3 software as well as using previously developed pipeline. Variants analysis and interpretation were based on phenotype gene target approach, literature and databases search, allele frequency, and pathogenicity prediction by in silico software. Causative variants were confirmed by Sanger sequencing. Whenever possible, additional family members were studied for segregation analysis. We identified a likely genetic cause of MD in 5 cases. CE panel analysis revealed 7 different missense and one splice site pathogenic/likely pathogenic variants in 5 genes related to rare neurodegenerative disorders. Detected pathogenic/likely pathogenic variants in the TUBB4A, PANK2, SETX, MFSD8, and ARSA genes have been compatible with the clinical phenotype of the patients. Furthermore, in additional three cases variants in the DCTN1, PDGFRB, and POLG genes have been detected as a possible cause of disease. In the rest of the studied cases, genetic diagnosis remains unclear. These results emphasize the significance of CE panel analysis in elucidating the diagnosis of neurodegenerative diseases manifesting by movement disorders and gave us insight into the complexity of the genetic background of this group of disorders.

We aimed to detect the causative gene in five unrelated families with recessive inheritance pattern neurological disorders involving the central nervous system, and the potential function of the NEMF gene in the central nervous system. Exome sequencing (ES) was applied to all families and linkage analysis was performed on family 1. A minigene assay was used to validate the splicing effect of the relevant discovered variants. Immunofluorescence (IF) experiment was performed to investigate the role of the causative gene in neuron development. The large consanguineous family confirms the phenotype-causative relationship with homozygous frameshift variant (NM_004713.6:c.2618del) as revealed by ES. Linkage analysis of the family showed a significant single-point LOD of 4.5 locus. Through collaboration in GeneMatcher, four additional unrelated families' likely pathogenic NEMF variants for a spectrum of central neurological disorders, two homozygous splice-site variants (NM_004713.6:c.574+1G>T and NM_004713.6:c.807-2A>C) and a homozygous frameshift variant (NM_004713.6: c.1234_1235insC) were subsequently identified and segregated with all affected individuals. We further revealed that knockdown (KD) of Nemf leads to impairment of axonal outgrowth and synapse development in cultured mouse primary cortical neurons. Our study demonstrates that disease-causing biallelic NEMF variants result in central nervous system impairment and other variable features. NEMF is an important player in mammalian neuron development.

BACKGROUND The group of dystonia genes is expanding, and mutations of these genes have been associated with various combined dystonia syndromes. Among the latter, the cause of some dystonia parkinsonism cases remains unknown. OBJECTIVE To report patients with early-onset dystonia parkinsonism as a result of loss-of-function mutations in nuclear receptor subfamily 4 group A member 2. METHODS Phenotypic characterization and exome sequencing were carried out in 2 families. RESULTS The 2 patients reported here both had a history of mild intellectual disability in childhood and subsequently developed dystonia parkinsonism in early adulthood. Brain magnetic resonance imaging was normal, and DATscan suggested bilateral dopaminergic denervation. Two frameshift mutations in NR4A2 were identified: a de novo insertion (NM_006186.3; c.326dupA) in the first case and another small insertion (NM_006186.3; c.881dupA) in the second. CONCLUSIONS NR4A2 haploinsufficiency mutations have been recently reported in neurodevelopmental phenotypes. Our findings indicate that dystonia and/or parkinsonism may appear years after initial symptoms. Mutations in NR4A2 should be considered in patients with unexplained dystonia parkinsonism. © 2020 International Parkinson and Movement Disorder Society.

To report on the novel association of biallelic variant in atonal basic helix-loop-helix transcription factor 1 (A detailed clinical assessment and exome sequencing of peripheral blood sample were performed. Segregation analysis with Sanger sequencing and structural modeling of the variant was performed to support the pathogenicity of the variant.A homozygous missense variant (NM_005172.1:c.481CG) in theBased on the sequencing results and evidence from structural modeling of the identified variant, as well as with previous reports of

We report the case of a 41-year-old man on conservative treatment for more than 20 years for chronic renal insufficiency, chronic hepatitis and recurrent cholangitis. Following lengthy and extensive diagnostics, the differential diagnosis included primary sclerosing cholangitis and Caroli’s disease (CD). To solve the diagnostic challenge, next generation sequencing (NGS) was performed to distinguish between the disorders possibly present in the patient. The diagnosis of CD became evident after two rare known pathogenic mutations were detected in the poly-ductin 1 (PKHD1) gene, c.370C>T (p.Arg124Ter) and c.4870C>T (p.Arg1624Trp). In this case, NGS was instrumental in solving the diagnostic challenge, allowing differentiation among the proposed genetic and non-genetic ethiologies.

Summary Activating Signal Cointegrator 1 Complex, Subunit 3 (ASCC3) is part of the four-part ASC-1 transcriptional cointegrator complex. This complex includes ASCC1 (associated with spinal muscular atrophy with congenital bone fractures 2), TRIP4 (associated with spinal muscular atrophy with congenital bone fractures 1), and ASCC2 (not yet associated with human disease.) ASCC3 encodes a DNA helicase responsible for generating single-stranded DNA as part of the DNA damage response. Interestingly, ASCC3 expresses coding and non-coding isoforms, which act in opposition to balance the recovery of gene transcription after UV-induced DNA damage. Here we report the discovery of ASCC3 as the cause of a neuromuscular syndrome in seven unreported individuals from six unrelated families and updates on the one previously reported family. All the individuals share a neurologic phenotype that ranges from severe developmental delay to muscle fatigue. There appears to be genotype-phenotype correlation, as the most mildly affected individual is homozygous for a rare missense variant, while the more severely affected individuals are compound heterozygotes for a missense and a presumed loss-of-function (LOF) variant. There are no individuals with biallelic presumed LOF variants in our cohort or in gnomAD, as this genotype may not be compatible with life. In summary we report a syndrome in these eleven individuals from seven families with biallelic variants in ASCC3., Although other members of the ASC-1 transcriptional cointegrator complex are associated with severe neuromuscular syndromes, the phenotype of Activating Signal Cointegrator 1 Complex, Subunit 3 (ASCC3) has not previously been delineated. Here we describe 11 individuals with a variable pediatric-onset neuromuscular syndrome caused by biallelic variants in ASCC3.

Several patients with rare genetic disorders remain undiagnosed following comprehensive diagnostic testing using whole-exome sequencing (WES). In these patients, pathogenic genetic variants may reside in intronic or regulatory regions or they may emerge through mutational mechanisms not detected by WES. For this reason, we implemented whole-genome sequencing (WGS) in routine clinical diagnostics of patients with undiagnosed genetic disorders and report on the outcome in 30 patients. Criteria for consideration included (1) negative WES, (2) a high likelihood of a genetic cause for the disorders, (3) positive family history, (4) detection of large blocks of homozygosity or (5) detection of a single pathogenic variant in a gene associated with recessive conditions. We successfully discovered a causative genetic variant in 6 cases, a retrotranspositional event in the APC gene, non-coding variants in the intronic region of the OTC gene and the promotor region of the UFM1 gene, repeat expansion in the RFC1 gene and a single exon duplication in the CNGB3 gene. We also discovered one coding variant, an indel, which was missed by variant caller during WES data analysis. Our study demonstrates the impact of WGS in the group of patients with undiagnosed genetic diseases after WES in the clinical setting and the diversity of mutational mechanisms discovered, which would remain undetected using other methods.

In recent years, late-onset schizophrenia is a subject of controversial debate in the medical profession largely due to difficulties in reaching a consensus on the diagnosis of the disorder. In the present article we try to summarize in one place the scientific resources that were studying this disorder in the past decades and present a comprehensive overview from diagnosis to treatment of this relatively common disorder. Late-onset schizophrenia differs from early-onset schizophrenia in terms of symptoms, treatment, prognosis and pathogenesis, which is in early-onset schizophrenia based mainly on the developmental causes, whereas late-onset schizophrenia is most likely the result of a degenerative process within the central nervous system. Differential diagnosis of this disorder can be especially challenging and therefore demands additional attention. It is necessary to exclude degenerative diseases, expansive processes, neurological and psychiatric disorders, and ultimately, the abuse of psychoactive substances. Lately, there has been a lot of research done on genetic causes that could explain pathogenesis of the disorder, however, knowledge of the genetic influence for the establishment of clinical diagnosis is at this moment still inadequate. Thus, a clinical examination of the patient still remains the gold standard for the diagnosis of late-onset schizophrenia. Finally, we highlight the particularities of pharmacotherapy and summarize the current treatment guidelines for late-onset schizophrenia.

PurposeWe sought to determine the analytical sensitivity of several extended exome variation analysis approaches in terms of their contribution to diagnostic yield and their clinical feasibility.MethodsWe retrospectively analyzed the results of genetic testing in 1,059 distinct cases referred for exome sequencing to our institution. In these, we routinely employed extended exome analysis approaches in addition to basic variant analysis, including (i) copy-number variation (CNV) detection, (ii) nonconsensus splice defect detection, (ii) genomic breakpoint detection, (iv) homozygosity mapping, and (v) mitochondrial variant analysis.ResultsExtended exome analysis approaches assisted in identification of causative genetic variant in 44 cases, which represented a 4.2% increase in diagnostic yield. The greatest contribution was associated with CNV analysis (1.8%) and splice variant prediction (1.2%), and the remaining approaches contributed an additional 1.2%. Analysis of workload has shown that on average nine additional variants per case had to be interpreted in the extended analysis.ConclusionWe show that extended exome analysis approaches improve the diagnostic yield of heterogeneous genetic disorders and result in considerable increase of diagnostic yield of exome sequencing with a minor increase of interpretative workload.