De novo SPAST mutations may cause a complex SPG4 phenotype

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Biallelic Variants in the COLGALT1 Gene Causes Severe Congenital Porencephaly: A Case Report

Contains fulltext : 231725.pdf (publisher's version ) (Open Access)OBJECTIVE: We describe a third patient with brain small vessel disease 3 (BSVD3), being the first with a homozygous essential splice site variant in the COLGALT1 gene, with a more severe phenotype than the 2 children reported earlier. METHODS: Analysis of whole exome sequencing (WES) data of the child and parents was performed. We validated the missplicing of the homozygous variant using reverse transcription PCR and Sanger sequencing of the mRNA in a lymphocyte culture. RESULTS: The patient presented antenatally with porencephaly on ultrasound and MRI. Postnatally, he showed a severe developmental delay, refractory epilepsy, spastic quadriplegia, and a progressive hydrocephalus. WES revealed a homozygous canonical splice site variant NM_024656.3:c.625-2A>C. PCR and Sanger sequencing of the mRNA demonstrated that 2 cryptic splice sites are activated, causing a frameshift in the major transcript and in-frame deletion in a minor transcript. CONCLUSIONS: We report a third patient with biallelic pathogenic variants in COLGALT1, confirming the role of this gene in autosomal recessive BSVD3

Saccadic peak velocity and EEG as end-points for a serotonergic challenge test.

We previously reported that a single dose of the serotonin receptor agonist meta-chlorophenylpiperazine increased the peak velocity of saccadic eye movements and decreased low-frequency electroencephalographic activity. METHODS: We administered a single dose of the serotonin releaser dexfenfluramine in a double blind, placebo controlled randomised cross-over design and measured saccadic eye movements and EEG every hour up to 6 h. Subjects were 62 males (18-30 years) with a history of no, moderate or heavy use of ecstasy tablets. RESULTS: Dexfenfluramine increased saccadic peak velocity and decreased alpha, delta and theta electroencephalographic activity, the latter predominantly in heavy users of ecstasy. CONCLUSIONS: This study supports the idea that saccadic peak velocity and EEG can be useful endpoints of a serotonergic challenge. This could be an important anatomical extension of these end-points, which until now were limited to the effect on hypothalamic serotonergic projections

The complexities of CACNA1A in clinical neurogenetics

Variants in CACNA1A are classically related to episodic ataxia type 2, familial hemiplegic migraine type 1, and spinocerebellar ataxia type 6. Over the years, CACNA1A has been associated with a broader spectrum of phenotypes. Targeted analysis and unbiased sequencing of CACNA1A result not only in clear molecular diagnoses, but also in large numbers of variants of uncertain significance (VUS), or likely pathogenic variants with a phenotype that does not directly match the CACNA1A spectrum. Over the last years, targeted and clinical exome sequencing in our center has identified 41 CACNA1A variants. Ultimately, variants were considered pathogenic or likely pathogenic in 23 cases, with most phenotypes ranging from episodic or progressive ataxia to more complex ataxia syndromes, as well as intellectual disability and epilepsy. In two cases, the causality of the variant was discarded based on non-segregation or an alternative diagnosis. In the remaining 16 cases, the variant was classified as uncertain, due to lack of opportunities for segregation analysis or uncertain association with a non-classic phenotype. Phenotypic variability and the large number of VUS make CACNA1A a challenging gene for neurogenetic diagnostics. Accessible functional read-outs are clearly needed, especially in cases with a non-classic phenotype

Antisense BCR-ABL oligonucleotides induce apoptosis in the Philadelphia chromosome-positive cell line BV173.

BCR-ABL antisense oligonucleotides can specifically reduce colony formation of early hematopoietic progenitor cells from chronic myeloid leukemia (CML) patients. Little is known about the mechanism of this inhibition. We studied the inhibition of the bcr-abl oncogene using fluorescein-labeled phosphorothioate oligonucleotides in the Philadelphia chromosome-positive cell line BV173. Oligonucleotide stability, uptake, bcr-abl mRNA degradation, inhibition of cell proliferation, and cell death were studied. The oligonucleotide uptake was directly dependent on the extracellular concentration and was constant over the first 18 h of incubation. After that the uptake rate decreased. We detected a decrease in bcr-abl mRNA after 3 days of treatment with antisense oligonucleotides, but much less in controls. The controls used in the experiments were the sense oligonucleotide, equimolar amounts of sense and antisense, and an untreated control. Antisense oligonucleotides completely inhibited cell growth of BV173 cells and did not inhibit growth of HL-60 cells, whereas control oligonucleotides had no such effect on either cell line. An oligonucleotide specific for the other CML breakpoint was also effective in reducing cell growth of BV173. By the use of a DNA double staining technique to discriminate between necrotic and apoptotic cells, we detected a large number of apoptotic cells in antisense treated BV173 cultures after 5 days of treatment as compared to controls. We conclude that antisense BCR-ABL oligonucleotides reduce bcr-abl mRNA expression in BV173 cells mainly in a sequence-specific manner and induce apoptosis

Clinical exome sequencing for cerebellar ataxia and spastic paraplegia uncovers novel gene-disease associations and unanticipated rare disorders

Neurological Motor Disorder

Ear and hearing problems in relation to karyotype in children with Turner syndrome

Item does not contain fulltextThe aim of the study was to report otologic and audiologic characteristics in a group of children with Turner syndrome (TS) and correlate these findings to karyotype. Additionally, we give recommendations for the otologic care of these children. Sixty children (age 1.7-21.2 years) were included in this retrospective study. Medical history and karyotypes were recorded and otologic and audiologic evaluation was performed. A history of recurrent otitis media was reported in 41/60 (68%) children and 3/60 (5%) had suffered from cholesteatoma. Audiometric data in 56 children revealed that normal hearing was only present in 33/112 (29%) ears. All other ears 79/112 (71%) were classified in five different audiometric categories for hearing loss. Hearing thresholds in general appeared to be about 10-11 dB worse in children with a monosomy 45,X or isochromosome (both have a total deletion of the short (p) arm of the X-chromosome) compared to those having a mosaicism or structural anomaly (partial deletion, or total deletion in only a few cells). Our findings support the hypothesis that hearing can be affected by loss of the p-arm of the X-chromosome. It is for the first time that a relation between hearing problems and karyotype is statistically confirmed in a large group of children with TS

Copy number variants from 4800 exomes contribute to similar to 7% of genetic diagnoses in movement disorders, muscle disorders and neuropathies

Various groups of neurological disorders, including movement disorders and neuromuscular diseases, are clinically and genetically heterogeneous. Diagnostic panel-based exome sequencing is a routine test for these disorders. Despite the success rates of exome sequencing, it results in the detection of causative sequence variants in 'only' 25-30% of cases. Copy number variants (CNVs), i.e. deletion or duplications, explain 10-20% of individuals with multisystemic phenotypes, such as co-existing intellectual disability, but may also have a role in disorders affecting a single system (organ), like neurological disorders with normal intelligence. In this study, CNVs were extracted from clinical exome sequencing reports of 4800 probands primarily with a movement disorder, myopathy or neuropathy. In 88 (similar to 2%) probands, phenotype-matching CNVs were detected, representing similar to 7% of genetically confirmed cases. CNVs varied from involvement of over 100 genes to single exons and explained X-linked, autosomal dominant, or recessive disorders, the latter due to either a homozygous CNV or a compound heterozygous CNV with a sequence variant on the other allele. CNVs were detected affecting genes where deletions or duplications are established as a common mechanism, like PRKN (in Parkinson's disease), DMD (in Duchenne muscular dystrophy) and PMP22 (in neuropathies), but also genes in which no intragenic CNVs have been reported to date. Analysis of CNVs as part of panel-based exome sequencing for genetically heterogeneous neurological diseases provides an additional diagnostic yield of similar to 2% without extra laboratory costs. Therefore it is recommended to perform CNV analysis for movement disorders, muscle disease, neuropathies, or any other single-system disorder

Upstream SLC2A1 translation initiation causes GLUT1 deficiency syndrome

Contains fulltext : 174080.pdf (publisher's version ) (Closed access)Glucose transporter type 1 deficiency syndrome (GLUT1DS) is a neurometabolic disorder with a complex phenotypic spectrum but simple biomarkers in cerebrospinal fluid. The disorder is caused by impaired glucose transport into the brain resulting from variants in SCL2A1. In 10% of GLUT1DS patients, a genetic diagnosis can not be made. Using whole-genome sequencing, we identified a de novo 5'-UTR variant in SLC2A1, generating a novel translation initiation codon, severely compromising SLC2A1 function. This finding expands our understanding of the disease mechanisms underlying GLUT1DS and encourages further in-depth analysis of SLC2A1 non-coding regions in patients without variants in the coding region

Cognitive performance and serotonergic function in users of ecstasy.

Item does not contain fulltextRATIONALE: () 3,4-Methylenedioxymethamphetamine (MDMA or "ecstasy") has been shown to cause long term damage to serotonergic cerebral neurons in animals. The neurotoxic effects in humans are less clear and little is known about the functional consequences, although some studies suggest memory impairment. Given the widespread use of MDMA, our lack of knowledge raises concerns. OBJECTIVE: We investigated, in humans, the relation between past use of ecstasy and cognitive performance as well as serotonergic function. Methods: Two groups of 21 males with moderate and heavy recreational use of MDMA, respectively, and a control group of 20 males without use of MDMA were compared. All were from the same subculture. Reaction time, direct recall, and recognition were assessed. Serotonergic function was measured by the neuro-endocrine response to a placebo-controlled, crossover challenge with dexfenfluramine. RESULTS: Ecstasy users showed a broad pattern of statistically significant, but clinically small, impairment of memory and prolonged reaction times. Heavy users were affected stronger than moderate users. Release of cortisol but not of prolactin after dexfenfluramine administration was significantly reduced in both groups of ecstasy users compared with the controls. Analyses of covariance showed that likely confounding variables including recent exposure to ecstasy, psychosocial profiles and use of other drugs did not explain the differences found between the groups. CONCLUSIONS: These results provide further evidence that use of ecstasy may be associated with impairment of memory and of serotonergic function. These findings are compatible with neurotoxicity of ecstasy as shown in animals