Truncating SRCAP variants outside the Floating-Harbor syndrome locus cause a distinct neurodevelopmental disorder with a specific DNA methylation signature

Truncating variants in exons 33 and 34 of the SNF2-related CREBBP activator protein (SRCAP) gene cause the neurodevelopmental disorder (NDD) Floating-Harbor syndrome (FLHS), characterized by short stature, speech delay, and facial dysmorphism. Here, we present a cohort of 33 individuals with clinical features distinct from FLHS and truncating (mostly de novo) SRCAP variants either proximal (n = 28) or distal (n = 5) to the FLHS locus. Detailed clinical characterization of the proximal SRCAP individuals identified shared characteristics: developmental delay with or without intellectual disability, behavioral and psychiatric problems, non-specific facial features, musculoskeletal issues, and hypotonia. Because FLHS is known to be associated with a unique set of DNA methylation (DNAm) changes in blood, a DNAm signature, we investigated whether there was a distinct signature associated with our affected individuals. A machine-learning model, based on the FLHS DNAm signature, negatively classified all our tested subjects. Comparing proximal variants with typically developing controls, we identified a DNAm signature distinct from the FLHS signature. Based on the DNAm and clinical data, we refer to the condition as "non-FLHS SRCAP-related NDD.'' All five distal variants classified negatively using the FLHS DNAm model while two classified positively using the proximal model. This suggests divergent pathogenicity of these variants, though clinically the distal group presented with NDD, similar to the proximal SRCAP group. In summary, for SRCAP, there is a clear relationship between variant location, DNAm profile, and clinical phenotype. These results highlight the power of combined epigenetic, molecular, and clinical studies to identify and characterize genotype-epigenotype-phenotype correlations.Genetics of disease, diagnosis and treatmen

Molecular characterization of febrile seizures and temporal lobe epilepsy : towards unraveling epileptogenesis and febrile seizure susceptibility

Epilepsy is a neurological disorder that is characterized by recurrent seizures and affects about 1% of the population worldwide. Epilepsy can occur because of a genetic predisposition, because of acquired factors or because of a combination between the two (multifactorial). Temporal lobe epilepsy (TLE) is considered to be the most common partial epilepsy type with extensive etiological heterogeneity. Most cases probably can be classified as mulitfactorial. Although much progress has been made about the understanding of TLE, the molecular mechanisms involved in the etiology and neuropathology of TLE remain poorly understood. Febrile seizures (FS) are the most common initial precipitating event in mesial TLE (MTLE), but it is unclear whether FS themselves contribute to the development of MTLE, or whether a prenatal lesion, brain insult or a genetic predisposition is causal to both FS and MTLE . We demonstrate that the innate immune system plays an important role in human MTLE and that an acquired Navb3 channelopathy had developed in a subset of human MTLE patients. Chemokines were identified as highly regulated in human MTLE, and therefore the effects of these chemokines on hippocampal neurons were investigated. We showed that the chemokine CCL3 can alter neuronal activity and calcium dynamics in cultured hippocampal neurons by increasing NMDA receptor levels. To investigate the longitudinal effects of FS and to identify FS susceptibility genes we developed and validated two FS models in mice. We also showed that mouse FS susceptibility is influenced by a complex genetic background. Longitudinal effects of FS in the hippocampus were investigated using microarrays, which showed us that prolonged FS acutely induce transcriptional and heat-shock responses, and on the more long-term induce network reorganizations and reduced expression of Camk2a. FS susceptibility was investigated in more detail using a chromosome substitution mouse panel. We identified FS susceptibility loci on chromosomes 1, 2, 10, 13 and X. Using mice haploinsufficient for glutamine synthetase (Glul or GS), we characterized Glul as a major FS susceptibility gene. In the next sections results presented in this thesis are discussed in the context of MTLE, FS and epileptogenesis. These studies provide insight in the emerging role of the immune system in MTLE and identify genes and processes involved in FS and epileptogenesis. In human MTLE we identified high expression of chemokines, which in vitro increased neuronal activity. Blocking chemokines could prove beneficial to MTLE patients and is of interest for future studies. FS were shown to induce a process of epileptogenesis possibly culminating in MTLE in which Camk2a plays a key role. The role of Camk2a is currently being investigated in more detail. Although FS predispose to MTLE, we showed that genes influencing FS and epileptogenesis susceptibility are distinct. Glul was shown to be a major FS susceptibility gene and FS susceptibility loci have been localized to chromosomes 1, 2, 10, 13 and X of the A/J strain. Fine-mapping and subsequent sequencing will be necessary to identify causative genes and will increase our understanding of the FS/MTLE mechanisms and relationships

Molecular characterization of febrile seizures and temporal lobe epilepsy : towards unraveling epileptogenesis and febrile seizure susceptibility

Epilepsy is a neurological disorder that is characterized by recurrent seizures and affects about 1% of the population worldwide. Epilepsy can occur because of a genetic predisposition, because of acquired factors or because of a combination between the two (multifactorial). Temporal lobe epilepsy (TLE) is considered to be the most common partial epilepsy type with extensive etiological heterogeneity. Most cases probably can be classified as mulitfactorial. Although much progress has been made about the understanding of TLE, the molecular mechanisms involved in the etiology and neuropathology of TLE remain poorly understood. Febrile seizures (FS) are the most common initial precipitating event in mesial TLE (MTLE), but it is unclear whether FS themselves contribute to the development of MTLE, or whether a prenatal lesion, brain insult or a genetic predisposition is causal to both FS and MTLE . We demonstrate that the innate immune system plays an important role in human MTLE and that an acquired Navb3 channelopathy had developed in a subset of human MTLE patients. Chemokines were identified as highly regulated in human MTLE, and therefore the effects of these chemokines on hippocampal neurons were investigated. We showed that the chemokine CCL3 can alter neuronal activity and calcium dynamics in cultured hippocampal neurons by increasing NMDA receptor levels. To investigate the longitudinal effects of FS and to identify FS susceptibility genes we developed and validated two FS models in mice. We also showed that mouse FS susceptibility is influenced by a complex genetic background. Longitudinal effects of FS in the hippocampus were investigated using microarrays, which showed us that prolonged FS acutely induce transcriptional and heat-shock responses, and on the more long-term induce network reorganizations and reduced expression of Camk2a. FS susceptibility was investigated in more detail using a chromosome substitution mouse panel. We identified FS susceptibility loci on chromosomes 1, 2, 10, 13 and X. Using mice haploinsufficient for glutamine synthetase (Glul or GS), we characterized Glul as a major FS susceptibility gene. In the next sections results presented in this thesis are discussed in the context of MTLE, FS and epileptogenesis. These studies provide insight in the emerging role of the immune system in MTLE and identify genes and processes involved in FS and epileptogenesis. In human MTLE we identified high expression of chemokines, which in vitro increased neuronal activity. Blocking chemokines could prove beneficial to MTLE patients and is of interest for future studies. FS were shown to induce a process of epileptogenesis possibly culminating in MTLE in which Camk2a plays a key role. The role of Camk2a is currently being investigated in more detail. Although FS predispose to MTLE, we showed that genes influencing FS and epileptogenesis susceptibility are distinct. Glul was shown to be a major FS susceptibility gene and FS susceptibility loci have been localized to chromosomes 1, 2, 10, 13 and X of the A/J strain. Fine-mapping and subsequent sequencing will be necessary to identify causative genes and will increase our understanding of the FS/MTLE mechanisms and relationships

The c.1A > C start codon mutation in CLN3 is associated with a protracted disease course

Contains fulltext : 220479.pdf (publisher's version ) (Open Access)BACKGROUND: CLN3 disease is a disorder of lysosomal homeostasis predominantly affecting the retina and the brain. The severity of the underlying mutations in CLN3 particularly determines onset and course of neurological deterioration. Given the highly conserved start codon code among eukaryotic species, we expected a variant in the start codon of CLN3 to give rise to the classical, that is, severe, phenotype. CASE SERIES: We present three patients with an identical CLN3 genotype (compound heterozygosity for the common 1 kb deletion in combination with a c.1A > C start codon variant) who all displayed a more attenuated phenotype than expected. While their retinal phenotype was similar to as expected in classical CLN3 disease, their neurological phenotype was delayed. Two patients had an early onset of cognitive impairment, but a particularly slow deterioration afterwards without any obvious motor impairment. The third patient also had a late onset of cognitive impairment. CONCLUSIONS: Contrasting our initial expectations, patients with a start codon variant in CLN3 may display a protracted phenotype. Future work will have to reveal the exact mechanism behind the assumed residual protein synthesis, and determine whether this may be eligible to start codon targeted therapy

Hippocampal Nabeta3 expression in patients with temporal lobe epilepsy.

Contains fulltext : 80469.pdf (publisher's version ) (Closed access)Voltage-dependent sodium channels consist of a pore-forming alpha-subunit and regulatory beta-subunits. Alterations in these channels have been implicated in temporal lobe epilepsy (TLE) and several genetic epilepsy syndromes. Recently we identified Na(v)beta3 as a TLE-regulated gene. Here we performed a detailed analysis of the hippocampal expression of Na(v)beta3 in TLE patients with hippocampal sclerosis (HS) and without HS (non-HS) and compared expression with autopsy controls (ACs). Immunoblot analysis showed that Na(v)beta3 levels were dramatically reduced in the hippocampus, but not in the cortex of non-HS patients when compared to HS patients. This was confirmed by immunohistochemistry showing reduced Na(v)beta3 expression in all principal neurons of the hippocampus proper. Sequence analysis revealed no Na(v)beta3 mutations. The functional consequences of the reduced Na(v)beta3 expression in non-HS patients are unknown. Altered Na(v)beta3 expression might influence microcircuitry in the hippocampus, affecting excitability and contributing to epileptogenesis in non-HS patients. Further experiments are required to elucidate these functional possibilities

The p.Ala510Val mutation in the SPG7 (paraplegin) gene is the most common mutation causing adult onset neurogenetic disease in patients of British ancestry

The c.1529C >T change in the SPG7 gene, encoding the mutant p.Ala510Val paraplegin protein, was first described as a polymorphism in 1998. This was based on its frequency of 3 % and 4 % in two separate surveys of controls in the United Kingdom (UK) population. Subsequently, it has been found to co-segregate with disease in a number of different populations. Yeast expression studies support its having a deleterious effect. In this paper a consanguineous sibship is described in which four members who are homozygous for the p.Ala510Val variant present with a spectrum of disease. This spectrum encompasses moderately severe hereditary spastic paraparesis (HSP) with more minor ataxia in two siblings, moderately severe ataxia without spasticity in the third, and a very mild gait ataxia in the fourth. Two of the siblings also manifest vestibular failure. The remaining eight unaffected siblings are either heterozygous for the p.Ala510Val variant, or do not carry it at all. Homozygosity mapping using a high-density SNP array across the whole genome found just 11 genes (on two regions of chromosome 3) outside the SPG7 region on chromosome 16, which were homozygously shared by the affected siblings, but not shared by the unaffected siblings; none of them are likely to be causative. The weight of evidence is strongly in favour of the p.Ala510Val variant being a disease-causing mutation. We present additional data from the Auckland City Hospital neurogenetics clinic to show that the p.Ala510Val mutation is prevalent amongst HSP patients of UK extraction belying any suggestion that European p.Ala510Val haplotypes harbour a disease-causing mutation which the UK p.Ala510Val haplotypes do not. Taken together with previous findings of a carrier frequency of 3-4 % in the UK population (giving a homozygosity rate of 20-40/100,000), the data imply that the p.Ala510Val is the most common mutation causing neurogenetic disease in adults of UK ancestry, albeit the penetrance may be low or the disease caused may be mild

Parenteral hydroxocobalamin dose intensification in five patients with different types of early onset intracellular cobalamin defects: Clinical and biochemical responses

Contains fulltext : 208821.pdf (publisher's version ) (Open Access

Parenteral hydroxocobalamin dose intensification in five patients with different types of early onset intracellular cobalamin defects: Clinical and biochemical responses

Intracellular cobalamin metabolism (ICM) defects can be present as autosomal recessive or X-linked disorders. Parenteral hydroxocobalamin (P-OHCbl) is the mainstay of therapy, but the optimal dose has not been determined. Despite early treatment, long-term complications may develop. We have analyzed the biochemical and clinical responses in five patients with early onset of different types of ICM defects (cblC: patients 1-3; cblA: patient 4; cblX: patient 5) following daily P-OHCbl dose intensification (DI). In patient 4, P-OHCbl was started at age 10 years and in patient 5 at age 5 years. OHCbl was formulated at either, 5, 25, or 50 mg/mL. P-OHCbl was intravenously or subcutaneously (SQ) delivered, subsequently by placement of a SQ injection port except in patient 4. In all patients, homocysteine and methylmalonic acid levels, demonstrated an excellent response to various P-OHCbl doses. After age 36 months, patients 1-3 had a close to normal neurological examination with lower range developmental quotient. In patient 3, moderate visual impairment was present. Patient 4, at age 10 years, had normal renal, visual and cognitive function. In cblX patient 5, epilepsy was better controlled. In conclusion, P-OHCbl-DI caused an excellent control of metabolites in all patients. In the three cblC patients, comparison with patients, usually harboring identical genotype and similar metabolic profile, was suggestive of a positive effect, in favor of clinical efficacy. With P-OHCbl-DI, CblA patient has been placed into a lower risk to develop renal and optic impairment. In cblX patient, lower P-OHCbl doses were administrated to improve tolerability.SCOPUS: ar.kinfo:eu-repo/semantics/publishe

Den osynlige fotbollsspelaren : Redovisning av fotbollsspelare på balansräkningen

Problem: Genom Svenska Fotbollförbundets införande av elitlicensen får fotbollsklubbar redovisa inköpta spelare som en tillgång eller kostnadsföra utgiften direkt. Dock får ej icke förvärvade spelare aktiveras på balansräkningen. Syfte: Undersöka möjligheten att redovisa alla spelare i en fotbollsklubb ekonomiskt samt undersöka sätt att värdera spelare vilka saknar anskaffningspris. Även utreda om en sådan redovisning leder till en mer ekonomisk rättvisande bild av klubbarna och hur jämförbarheten mellan klubbarna påverkas. Vill väcka intresse kring problemen med spelarvärdering på balansräkningen. Genomförande: Studie av litteratur i ämnet, gällande lagar och Svenska Fotbollförbundets elitlicens. Material insamlades genom en kvalitativ undersökning i form av intervjuer av kunniga personer inom elitfotboll och redovisning. Materialet från litteratur och intervjuer sammankopplas och diskuteras. Slutsatser: Undersökningen visar att rådande regler för fotbollsklubbarnas redovisning är efter de möjligheter som finns utformade på ett bra sätt och att därmed endast förvärvade spelare kan aktiveras. Detta då objektiva värderingsmodeller för ej köpta spelare saknas och att detta krävs för att få ett korrekt värde på spelaren. Dagens regler ger inte en helt rättvisande bild av fotbollsklubbarna men dock så väl som är möjligt idag