DOK7 congenital myasthenic syndrome: case series and review of literature.

BACKGROUND: Congenital myasthenic syndromes (CMS) are among the most challenging differential diagnoses in the neuromuscular domain, consisting of diverse genotypes and phenotypes. A mutation in the Docking Protein 7 (Dok-7) is a common cause of CMS. DOK7 CMS requires different treatment than other CMS types. Regarding DOK7's special considerations and challenges ahead of neurologists, we describe seven DOK7 patients and evaluate their response to treatment. METHODS: The authors visited these patients in the neuromuscular clinics of Tehran and Kerman Universities of Medical Sciences Hospitals. They diagnosed these patients based on clinical findings and neurophysiological studies, which Whole Exome Sequencing confirmed. For each patient, we tried unique medications and recorded the clinical response. RESULTS: The symptoms started from birth to as late as the age of 33, with the mean age of onset being 12.5. Common symptoms were: Limb-girdle weakness in 6, fluctuating symptoms in 5, ptosis in 4, bifacial weakness in 3, reduced extraocular movement in 3, bulbar symptoms in 2 and dyspnea in 2 3-Hz RNS was decremental in 5 out of 6 patients. Salbutamol was the most effective. c.1124_1127dupTGCC is the most common variant; three patients had this variant. CONCLUSION: We strongly recommend that neurologists consider CMS in patients with these symptoms and a similar familial history. We recommend prescribing salbutamol as the first-choice treatment option for DOK7 patients.

Central nervous system reactivation of herpesviridae family in patients with COVID-19.

The objective of this study is to describe our COVID-19 patients with herpesviridae reactivation in the central nervous system (CNS). Four patients were described including two with acute encephalitis and two with acute encephalomyelitis. Three of four patients had abnormal findings on neuroimaging studies. One of four patients died, one survived with major neurological sequelae, and two others fully recovered. Herpesviridae reactivation in the CNS in patients with COVID-19 is a rare but serious coincidence. The optimal therapeutic management has not been investigated and until more information is available, it is prudent to treat these patients with appropriate antivirals with or without anti-inflammatory agents.

Immune response to COVID-19 vaccines among people living with human T-cell lymphotropic virus type 1 infection: a retrospective cohort study from Iran.

The effectiveness of COVID-19 vaccination is still unclear in individuals with underlying diseases such as HTLV-1 infection. This retrospective cohort study aimed to evaluate the humoral response of COVID-19 vaccines among people living with HTLV-1 (PLHTLV) in northeastern Iran. From December 2021 to October 2022, eighty-six HTLV-1+ subjects (50 males and 36 females; 47.7 ± 11.2 years) and 90 HTLV-1 seronegative individuals (age- and sex-matched convenient samples) were enrolled. The humoral immune response was evaluated by measuring different COVID-19 Abs in serum samples at least 28 days after receiving 2nd or 3rd doses of COVID-19 vaccines. Throughout all three rounds of immunization, Sinopharm was the most commonly used COVID-19 vaccine across all three immunization rounds. Compared to the HTLV-1- group, a significantly lower frequency of all four Abs activity was observed among PLHTLV:anti-nucleocapsid (66.3% vs 86.7%, p = 0·001), anti-spike (91.9% vs 98.9%, p = 0·027), RBD (90.7% vs 97.8%, p = 0·043), and neutralizing Abs (75.6% vs 95.5%, p < 0·001). Also, the frequency of all Abs in 28 patients with HAM/TSP was higher than that of 58 asymptomatic carriers, although this difference was statistically significant only in the case of anti-spike Abs (p = 0.002). Notably, PLHTLV-vaccinated against COVID-19 demonstrated significantly lower antibody activities, indicating a reduced humoral immune response to COVID-19 vaccines.

XCL1, a serum biomarker in neurological diseases; HTLV-1-associated myelopathy and multiple sclerosis.

The XCL1-XCR1 axis has a potential role in the recruitment of immune cells to the site of inflammation. The present study aimed to examine the relation of XCL1 serum levels with Multiple sclerosis (MS) and HTLV-1-associated myelopathy (HAM), as chronic inflammatory diseases of the central nervous system (CNS). DNA was extracted to evaluate HTLV-1 proviral load (PVL) using real-time PCR. Serum levels of XCL1 was determined by using an ELISA assay. The serum level of XCL1 was significantly higher in patients with HAM than that of asymptomatic carriers (ACs) and healthy controls (HCs) (p < 0.001 and p < 0.0001, respectively) and was also higher in MS patients compared to HCs (p < 0.0001). Moreover, the concentration of XCL1 serum level was significantly different between the ACs and HCs group (p < 0.0001). In conclusion, increased expression of XCL1 might contribute to the migration of autoreactive T cells to the central nervous system and play a critical role in the development and pathogenesis of inflammatory neurological diseases including HAM and MS.

Pentraxin 3, a serum biomarker in human T-cell lymphotropic virus type-1-associated myelopathy patients and asymptomatic carriers.

Human T-cell lymphotropic virus type 1 (HTLV-1) can induce a neuroinflammatory condition that leads to myelopathy. Pentraxin 3 (PTX3) is an acute-phase protein that its plasma concentration increases during inflammation. We aimed to determine whether PTX3 serum level is elevated in HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP) patients and HTLV-1 asymptomatic carriers (ACs) and evaluate its association with proviral load and clinical features. The serum level of PTX3 was measured using an enzyme-linked immunosorbent assay in 30 HAM patients, 30 HTLV-1 ACs, and 30 healthy controls. Also, the HTLV-1 proviral load was determined via real-time PCR technique. The findings showed that PTX3 serum level was significantly higher in HAM patients than in both asymptomatic carriers and healthy controls (p values < 0.0001). No correlation between PTX3 and the proviral load was observed in HAM patients and asymptomatic carriers (r = - 0.238, p = 0.205 and r = - 0.078, p = 0.681, respectively). The findings showed that there was no significant correlation between PTX3 and motor disability grading (MDG) (r = - 0.155, p = 0.41) nor urinary disturbance score (UDS) (r = - 0.238, p = 0.20). Higher levels of PTX3 are associated with HTLV-1-associated myelopathy compared to asymptomatic carriers. This finding may support the idea that PTX3 has the potential as a diagnostic biomarker.

Nonpharmacological interventions and outcomes in the management of complications of human T-cell lymphotropic virus type 1-related myelopathy/tropical spastic paraparesis: A systematic review.

Background: Human T-cell lymph tropic virus type 1 (HTLV-I)-related myelopathy/tropical spastic paraparesis (TSP) is a progressive inflammatory process affecting the spinal cord that occurs as a result of HTLV 1. The use of nonpharmacological approaches has always been one of the treatment strategies in these patients, but disagreement about these interventions and their results has led to their limited use. Therefore, this study aimed to identify nonpharmacological interventions and their consequences in these patients. Materials and Methods: We followed the Cochrane Handbook for systematic reviews of interventions. The present report is organized according to the preferred reporting items for systematic reviews and meta-analyses. This study was conducted at PubMed, Cochrane Library, Web of Science, and Scopus, among all published studies by December 30, 2021. Keywords were: HTLV-1, Human T-lymph tropic virus 1, HTLV-I-associated myelopathy, HAM/TSP, tropical spastic paraparesis, nonpharmacological intervention, nonpharmacological treatment, massage, physiotherapy, acupuncture, acupressure, and exercise. The quality of the studies was assessed using JADAD. Results: Of 288 articles, 11 were eligible for data extraction published between 2014 and 2021. 90/9% of studies were randomized clinical trials. 81/8% of articles were of high quality. The total sample size was 253 people, of which 137 (54/15%) were women. Approaches such as exercise and motion therapy, electrotherapy, behavioral therapy, and virtual reality can be used for these patients. With these interventions, results such as improved mobility and balance, physical condition, pain, quality of life, muscle spasticity, maximum inspiratory pressure, and urinary symptoms can be achieved. Conclusion: The most common physical therapy method used in studies was active and passive body movements, which are associated with positive results for patients. Due to the small sample size in this group of studies, it is necessary to conduct more clinical trials for more accurate conclusions. Furthermore, due to the limited number of studies that have used electrical stimulation or combined intervention packages, it is not possible to say with certainty what effect these methods have on patients. It is necessary to conduct more clinical trials.

Genomic variants causing mitochondrial dysfunction are common in hereditary lower motor neuron disease.

Hereditary lower motor neuron diseases (LMND) other than 5q-spinal muscular atrophy (5q-SMA) can be classified according to affected muscle groups. Proximal and distal forms of non-5q-SMA represent a clinically and genetically heterogeneous spectrum characterized by significant overlaps with axonal forms of Charcot-Marie-Tooth (CMT) disease. A consensus for the best approach to molecular diagnosis needs to be reached, especially in light of continuous novel gene discovery and falling costs of next-generation sequencing (NGS). We performed exome sequencing (ES) in 41 families presenting with non-5q-SMA or axonal CMT, 25 of which had undergone a previous negative neuromuscular disease (NMD) gene panel analysis. The total diagnostic yield of ES was 41%. Diagnostic success in the cohort with a previous NMD-panel analysis was significantly extended by ES, primarily due to novel gene associated-phenotypes and uncharacteristic phenotypic presentations. We recommend early ES for individuals with hereditary LMND presenting uncharacteristic or significantly overlapping features. As mitochondrial dysfunction was the underlying pathomechanism in 47% of the solved individuals, we highlight the sensitivity of the anterior horn cell and peripheral nerve to mitochondrial imbalance as well as the necessity to screen for mitochondrial disorders in individuals presenting predominant lower motor neuron symptoms.

Evaluation of iron, ferritin, copper, and ceruloplasmin along with proviral load in human T lymphotropic virus type 1-associated myelopathy.

Human T-cell lymphotropic virus type 1 (HTLV-1) infection can cause HTLV-I-associated myelopathy (HAM). In this study, we evaluated the levels of serum iron, ferritin, copper, and ceruloplasmin, and their correlations with HTLV-1 proviral load (PVL) and standard indices of HAM severity. In total, 114 subjects were recruited in this cross sectional study in Qaem Hospital, Mashhad, Iran between 2017 and 2018, including 36 HAM and 32 asymptomatic cases (ACs) and 46 healthy people (HSs). The clinical examination and evaluation of serum levels of biochemical factors and proviral load were performed. The PVL in HAM and ACs were 1835.49 ± 382.81 and 280.97 ± 67.41 copies/104 PBMCs, which statistically differed. Significant differences were also observed in plasma levels of iron, copper, and ceruloplasmin, among the three groups, while ferritin level was not considerably different. For HAM severity, the mean Osame motor disability scale (OMDS) and overactive bladder-validated-8-questionnaire (OABV-8) scores were 4.97 ± 0.38 and 15.75 ± 0.83, respectively, that had no significant correlations with the biochemical variables. Even though the studied elements in HAM group did not affect the severity of the disease, the levels of copper and ceruloplasmin might be determinants of the development and progression of HAM, as they are shown to play role in progression of other neurological diseases.

A significant association between CXCL10 -1447 A > G and IL18 -607 C > A gene polymorphism with human T-cell lymphotropic virus type 1 associated myelopathy/tropical spastic paraparesis (HAM-TSP), a case-control report from city of Mashhad, Iran.

Human T-cell lymphotropic virus type 1 (HTLV-1) is the first isolated retrovirus from humans, and 2-3% of infected individuals suffer from HTLV-1 associated myelopathy tropical spastic paraparesis (HAM-TSP). Previous studies indicated that the risk of HAM-TSP could be correlated with the individuals' genetic alterations. Mashhad is one of the areas infected with HTLV-1 in Iran. This study designed to examine the association between several important gene polymorphisms and HAM-TSP. Genotypes of 232 samples from controls, HTLV-1 carriers, and HAM-TSP patients were examined for FAS-670 (A > G), CXCL10-1447 (A > G), Foxp3-3279 (C > A), IL-18 -137 (C > G), and IL-18 -607 (C > A) gene polymorphisms by different polymerase chain reaction (PCR) techniques. A non-significant association was observed between FAS-670 A > G, Foxp3-3279 C > A, and IL-18 -137 C > G gene polymorphisms and HAM-TSP. Nevertheless, a significant (P < 0.001) association between CXCL10-1447 A > G and IL-18 -607 C > A gene polymorphisms with HAM-TSP was observed in our study population. As previous studies revealed that the CXCL10 level in the cerebrospinal fluid of HAM-TSP patients was associated with the disease progression, and as we noticed, a direct association was observed between CXCL10-1447 A > G polymorphism and HAM-TSP. These polymorphisms might be recommended as a valuable prediction criterion for the severity of the disease. The contradiction between our findings and other studies regarding IL-18 -607 C > A gene polymorphism might be associated with various factors such as genotypes frequency in diverse races and population heterogeneity in the city of Mashhad.

Nanomicellar Curcumin Supplementation Improves the Clinical Manifestations of HAM/TSP Patients.

BACKGROUND: HTLV-1 infection causes a chronic, progressive, demyelinating, neuroinflammatory disease called HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP). Treatment of HAM/TSP patients which have high levels of proviral load and pro-inflammatory markers is a challenge for clinicians. Therefore, we aimed to investigate the immunomodulatory, anti-inflammatory, and antiviral effects of curcumin in HAM/TSP patients. METHODS: In this study, 20 newly diagnosed HAM/TSP patients (2 men and 18 women) were enrolled and evaluated for clinical symptoms, HTLV-1 proviral load, Tax and HBZ expression, neopterin serum concentration, and complete blood count (CBC) before and 12 weeks after treatment with nanomicellar curcumin (80 mg/day, orally). RESULTS: Clinical symptoms such as the mean Osame Motor Disability Score and Ashworth Spasticity Scale Score were significantly improved after the treatment (P = 0.001 and P = 0.001). Sensory symptoms such as pain and paresthesia were significantly decreased in all of the patients (P = 0.001). Furthermore, urinary disorders, including urinary frequency, incontinence, and the feeling of incomplete bladder emptying, were significantly improved (P = 0.001, P = 0.003, and P = 0.03). However, the mean HTLV-1 proviral load (P = 0.97) and CBC were similar, whereas Tax, HBZ, and neopterin levels tend to increase after the treatment (P = 0.004, P = 0.08, and P = 0.04). CONCLUSION: Results suggest that curcumin can safely improve the clinical symptoms of HAM/TSP patients but has no observable positive effects on the HTLV-1 proviral load, Tax, and HBZ expression. Therefore, prolonged use or the use of curcumin with antiviral agents in addition to clinical signs and symptoms can reduce the HTLV-1 proviral load and the expression of functional viral factors such as Tax and HBZ.

Acupuncture in the treatment of HTLV-I-associated myelopathy / tropical spastic Paraparesis.

We investigate the possible effects of acupuncture on the improvement of neurological problems in HTLV-I-associated myelopathy/tropical spastic paraparesis (HAM/TSP)disease. Twenty patients with HAM/TSP were studied in this pre and post-test clinical trial. Urinary incontinence, global motor disability, spasticity, and pain severity were evaluated before, one month, and three-month after the intervention. Analyses demonstrated a significant reduction of urinary symptoms one month after acupuncture (P = 0.023). A significant improvement was observed in patients' pain and the spasticity at the upper extremity joints, one and three-month after the intervention (P < 0.05). This study suggests that body acupuncture can be used as a complementary treatment to improve HAM/TSP neurological symptoms.

Abnormal vitamin D and lipid profile in HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP) patients.

The HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP) is a neurodegenerative disease of host-HTLV-1 interactions. In many virus-associated diseases and multiple sclerosis, the importance of vitamin-D and lipid profile has been demonstrated, thus similarly, their impacts were evaluated in HAM/TSP patients, in this study. Vitamin D and lipid profile were assessed in 120 healthy subjects (HSs), along with a proviral load (PVL) in 91 HAM/TSPs and 169 HTLV-1 carriers (ACs). The mean level of triglyceride and LDL in the HAM/TSPs were higher than HSs (P = 0.008 and 0.008, respectively), but no significant difference has been found between ACs and HSs. However, the level of HDL and vitamin-D in the HAM/TSP subjects were lower than HSs (P = 0.01 and P = 0.006, respectively). In HTLV-1 infected subjects, PVL was statistically associated with cholesterol (R = 0.24, P = 0.038), triglycerides (R = 0.26, P = 0.01) and HDL (R = 0.28, P = 0.001), and in HAM/TSPs there was a strong association between the severity of the disease, as determined by the OMDS and cholesterol (P = 0.01). Furthermore, in the HAM/TSPs, positive correlations between vitamin-D and age (R = 0.23, P = 0.028) and triglycerides (R = 0.38, P = 0.001) were found, also a significant correlation between PVL and LDL (R = 0.21, P = 0.001) and a weak correlation between PVL and OMDS (R = 0.4, P = 0.07) were noted. However, there was no correlation between PVL and urinary disturbance. Furthermore, PVL range of more than 600 copies/104 lymphocytes had a strong correlation with OMDS (P = 0.05), but not with urinary disturbance. It's more likely that HAM/TSP patients have an imbalanced lipid profile and low levels of vitamin D and may represent a potentially useful target for intervention in HTLV-1 associated diseases.

Protective effect of N-acetylcysteine on oxaliplatin-induced neurotoxicity in patients with colorectal and gastric cancers: A randomized, double blind, placebo-controlled, clinical trial.

PURPOSE: Neuropathy is one of the most prevalent and dose-limiting side effects of platinum chemotherapeutic agents. N-acetylcysteine is an antioxidant thiol which is able to increase whole blood concentration of glutathione, which may be protective against chemotherapy-induced neuropathy. The aim of this study was to evaluate the effect of N-acetylcysteine on neurotoxicity induced by oxaliplatin in patients with gastric or colorectal cancers. METHODS: During this randomized, double-blinded, placebo-controlled clinical trial, the preventive effect of N-acetylcysteine effervescent tablets was assessed in comparison with placebo, on neuropathy occurrence. Thirty-two patients with colorectal or gastric cancer randomly received N-acetylcysteine (two 600 mg tablets) or placebo tablets 1 h before receiving oxaliplatin in dose in XELOX (oxaliplatin and capecitabine regimen) for eight courses of chemotherapy. Neuropathy severity was assessed after eight courses of chemotherapy based on National Cancer Institute Common Terminology for Adverse Events (NCI-CTCAE) criteria neuropathy grading scale and also sensory and motor electrophysiological assessment was performed by a neurologist. RESULTS: The NCI-CTCAE scale grade of patients in intervention group was significantly lower than placebo group after eight course of oxaliplatin (P = 0.01); however, the sensory electrophysiological assessment result was not significantly different (P = 0.501). No patient in both group had motor electrophysiological changes. CONCLUSION: The results of this study showed that N-acetylcysteine could reduce the incidence of the neuropathy induced by oxaliplatin and delay its occurrence in patients with gastric or colorectal cancers.

Curcumin increased the expression of c-FLIP in HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP) patients.

Human T-cell lymphotropic virus type 1 (HTLV-1)-associated myelopathy/tropical spastic paraparesis (HAM/TSP) disease is a chronic neuroinflammatory disease, which is associated with HTLV-1 infection. There is no effective and satisfactory treatment of HAM/TSP. It has been shown that curcumin exhibits modulatory effects on apoptosis and cytotoxicity-related molecules in HAM/TSP patients. In the present study, we examined the effect of curcumin on the gene expression of caspase-8, caspase-10, and anti-apoptotic protein c-FLIP, in HAM/TSP patients. Furthermore, we compared the expression of these molecules between HAM/TSP and asymptomatic carriers. Real-time PCR was performed to examine the mRNA expression of caspase-8, caspase-10, and c-FLIP in studied groups. The mRNA expression of caspase-8 and caspase-10 was similar before and after curcumin treatment in HAM/TSP patients (P > 0.05). The mRNA expression of c-FLIPL and c-FLIPs was higher after curcumin treatment compared with before treatment and significant differences were observed between the two groups (P = 0.004 and P = 0.044, respectively). The mRNA expression levels of caspase-8, caspase-10, c-FLIPL, and c-FLIPs were not statistically significant between HAM/TSP patients and asymptomatic carriers (P < 0.05). In conclusion, our results showed that curcumin increased the expression of c-FLIP in HAM/TSP patients which might suggest that, this molecule is involved in the apoptosis of HTLV-1-infected cells. Further studies with large sample size could be useful to clarify the role of this supplement in HAM/TSP patients.

HTLV-1-infected asymptomatic carriers compared to HAM/TSP patients over-express the apoptosis- and cytotoxicity-related molecules.

HTLV-1 infection causes a chronic progressive debilitating neuroinflammatory disease which is called, HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP). One of the host defense mechanisms against viral infection is apoptosis which may control HTLV-1 infection. Therefore, we aimed to investigate this process and its interaction with viral factors in HTLV-1-infected asymptomatic carriers (ACs) compared to HAM/TSP patients. Fas, FasL, TRAIL, perforin, granzyme A, granzyme B, and granulysin gene expression and serum levels of Fas, FasL, TRAIL, and granulysin in the peripheral blood of 21 sex- and age-matched healthy controls (HCs), ACs, and HAM/TSP patients were evaluated. Also, the level of granulysin secretion in the cell culture supernatant was measured. Finally, the correlation of the expression of these molecules with HTLV-1 proviral load (PVL), Tax, and HBZ mRNA expression was analyzed. ACs compared to HAM/TSP patients significantly over-expressed the Fas, FasL, TRAIL, perforin, and granzyme B molecules. Fas, FasL, TRAIL, and granulysin serum levels were not different among studied groups; whereas, the secretion of granulysin was significantly decreased in ACs and HAM/TSP patients compared to HCs. Also, HAM/TSP patients expressed higher levels of HTLV-1 PVL, Tax, and HBZ mRNA. In addition, in ACs, inverse correlations between the Fas, FasL, TRAIL, perforin, granzyme B, and granulysin levels with HBZ mRNA expression were seen. ACs compared to HAM/TSP patients over-expressed the apoptosis- and cytotoxicity-related molecules. It could be concluded that successful control of the HTLV-1 infection and suppression of HAM/TSP development stem from the strong apoptosis and cytotoxic activity in the peripheral blood of ACs.

Targeted sequencing with expanded gene profile enables high diagnostic yield in non-5q-spinal muscular atrophies.

Spinal muscular atrophies (SMAs) are a heterogeneous group of disorders characterized by muscular atrophy, weakness, and hypotonia due to suspected lower motor neuron degeneration (LMND). In a large cohort of 3,465 individuals suspected with SMA submitted for SMN1 testing to our routine diagnostic laboratory, 48.8% carried a homozygous SMN1 deletion, 2.8% a subtle mutation, and an SMN1 deletion, whereas 48.4% remained undiagnosed. Recently, several other genes implicated in SMA/LMND have been reported. Despite several efforts to establish a diagnostic algorithm for non-5q-SMA (SMA without deletion or point mutations in SMN1 [5q13.2]), data from large-scale studies are not available. We tested the clinical utility of targeted sequencing in non-5q-SMA by developing two different gene panels. We first analyzed 30 individuals with a small panel including 62 genes associated with LMND using IonTorrent-AmpliSeq target enrichment. Then, additional 65 individuals were tested with a broader panel encompassing up to 479 genes implicated in neuromuscular diseases (NMDs) with Agilent-SureSelect target enrichment. The NMD panel provided a higher diagnostic yield (33%) than the restricted LMND panel (13%). Nondiagnosed cases were further subjected to exome or genome sequencing. Our experience supports the use of gene panels covering a broad disease spectrum for diseases that are highly heterogeneous and clinically difficult to differentiate.

Expanding the clinical phenotype of IARS2-related mitochondrial disease.

BACKGROUND: IARS2 encodes a mitochondrial isoleucyl-tRNA synthetase, a highly conserved nuclear-encoded enzyme required for the charging of tRNAs with their cognate amino acid for translation. Recently, pathogenic IARS2 variants have been identified in a number of patients presenting broad clinical phenotypes with autosomal recessive inheritance. These phenotypes range from Leigh and West syndrome to a new syndrome abbreviated CAGSSS that is characterised by cataracts, growth hormone deficiency, sensory neuropathy, sensorineural hearing loss, and skeletal dysplasia, as well as cataract with no additional anomalies. METHODS: Genomic DNA from Iranian probands from two families with consanguineous parental background and overlapping CAGSSS features were subjected to exome sequencing and bioinformatics analysis. RESULTS: Exome sequencing and data analysis revealed a novel homozygous missense variant (c.2625C > T, p.Pro909Ser, NM_018060.3) within a 14.3 Mb run of homozygosity in proband 1 and a novel homozygous missense variant (c.2282A > G, p.His761Arg) residing in an ~ 8 Mb region of homozygosity in a proband of the second family. Patient-derived fibroblasts from proband 1 showed normal respiratory chain enzyme activity, as well as unchanged oxidative phosphorylation protein subunits and IARS2 levels. Homology modelling of the known and novel amino acid residue substitutions in IARS2 provided insight into the possible consequence of these variants on function and structure of the protein. CONCLUSIONS: This study further expands the phenotypic spectrum of IARS2 pathogenic variants to include two patients (patients 2 and 3) with cataract and skeletal dysplasia and no other features of CAGSSS to the possible presentation of the defects in IARS2. Additionally, this study suggests that adult patients with CAGSSS may manifest central adrenal insufficiency and type II esophageal achalasia and proposes that a variable sensorineural hearing loss onset, proportionate short stature, polyneuropathy, and mild dysmorphic features are possible, as seen in patient 1. Our findings support that even though biallelic IARS2 pathogenic variants can result in a distinctive, clinically recognisable phenotype in humans, it can also show a wide range of clinical presentation from severe pediatric neurological disorders of Leigh and West syndrome to both non-syndromic cataract and cataract accompanied by skeletal dysplasia.

How mental fatigue affects the neural sources of P300 component

Existence of allocentric and egocentric systems for human navigation, mediating spatial, and response learning, respectively, has so far been discussed. It is controversial whether navigational strategies and their underlying learning systems and, accordingly, the activation of their associated brain areas are independent/parallel or whether they functionally/causally interact in a competitive or in a cooperative manner to solve navigational tasks. The insights provided by neural networks involved in reward-based navigation attributed to individual involvement or interactions of learning systems have been surveyed. This paper characterizes the interactions of neural networks by constructing generative neural models and investigating their functional and effective connectivity patterns. A single-subject computer-based virtual reality environment was constructed to simulate a navigation task within a naturalistic large-scale space wherein participants were rewarded for using either a place, response, or mixed strategy at different navigational stages. First, functional analyses were undertaken to evaluate neural activities via mapping brain activation and making statistical inference. Effects of interest, spatial and response learning/retrieval, and their competition and cooperation were investigated. The optimal generative model was then estimated using dynamic casual modeling to quantify effective connectivities within the network. This analysis revealed how experimental conditions supported competition and cooperation strategies and how they modulated the underlying network. Results suggest that when navigational strategies cooperated, there were statistically significant, functional, and effective connectivities between hippocampus and striatum. However, when the strategies competed, effective connections were not established among these regions. Instead, connections between hippocampus/striatum and prefrontal cortex were strengthened. It can be inferred that a type of dynamical reconfiguration occurs within a network responsible for navigation when strategies interact either cooperatively or competitively. This supports adaptive causal organization of the brain when it is engaged with goal directed behavior.

Sleep microstructure dynamics and neurocognitive performance in obstructive sleep apnea syndrome patients.

The present study examined the relationship between the increment in cyclic alternating patterns (CAPs) in sleep electroencephalography and neurocognitive decline in obstructive Sleep Apnea Syndrome (OSAS) patients through source localization of the phase-A of CAPs. All-night polysomnographic recordings of 10 OSAS patients and 4 control subjects along with their cognitive profile using the Addenbrooke's Cognitive Examination (ACE) test were acquired. The neuropsychological assessment involved five key domains including attention and orientation, verbal fluency, memory, language and visuo-spatial skills. The standardized low-resolution brain electromagnetic tomography (sLORETA) tool was used to source-localize the phase-A of CAPs in sleep EEG aiming to investigate the correlation between CAP phase-A and cognitive functions. Our findings suggested a significant increase in CAP rates among OSAS subjects versus control subjects. Moreover, sLORETA revealed that CAP phase-A is mostly activated in frontoparietal cortices. As CAP rate increases, the activity of phase-A in such areas is dramatically enhanced leading to arousal instability, lower sleep efficiency and a possibly impaired cortical capacity to consolidate cognitive inputs in frontal and parietal areas during sleep. As such, cognitive domains including verbal fluency, memory and visuo-spatial skills which predominantly relate to frontoparietal areas tend to be affected. Based on our findings, CAP activity may possibly be considered as a predictor of cognitive decline among OSAS patients.

Improving the performance of P300-based BCIs by mitigating the effects of stimuli-related evoked potentials through regularized spatial filtering.

Objective.the P300-based brain-computer interface (BCI) establishes a communication channel between the mind and a computer by translating brain signals into commands. These systems typically employ a visual oddball paradigm, where different objects (linked to specific commands) are randomly and frequently intensified. Upon observing the target object, users experience an elicitation of a P300 event-related potential in their electroencephalography (EEG). However, detecting the P300 signal can be challenging due to its very low signal-to-noise ratio (SNR), often compromised by the sequence of visual evoked potentials (VEPs) generated in the occipital regions of the brain in response to periodic visual stimuli. While various approaches have been explored to enhance the SNR of P300 signals, the impact of VEPs has been largely overlooked. The main objective of this study is to investigate how VEPs impact P300-based BCIs. Subsequently, the study aims to propose a method for EEG spatial filtering to alleviate the effect of VEPs and enhance the overall performance of these BCIs.Approach.our approach entails analyzing recorded EEG signals from visual P300-based BCIs through temporal, spectral, and spatial analysis techniques to identify the impact of VEPs. Subsequently, we introduce a regularized version of the xDAWN algorithm, a well-established spatial filter known for enhancing single-trial P300s. This aims to simultaneously enhance P300 signals and suppress VEPs, contributing to an improved overall signal quality.Main results.analyzing EEG signals shows that VEPs can significantly contaminate P300 signals, resulting in a decrease in the overall performance of P300-based BCIs. However, our proposed method for simultaneous enhancement of P300 and suppression of VEPs demonstrates improved performance in P300-based BCIs. This improvement is verified through several experiments conducted with real P300 data.Significance.this study focuses on the effects of VEPs on the performance of P300-based BCIs, a problem that has not been adequately addressed in previous studies. It opens up a new path for investigating these BCIs. Moreover, the proposed spatial filtering technique has the potential to further enhance the performance of these systems.