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Journal of Medical Genetics Oct 2023Limb-girdle muscular dystrophies (LGMD) are a heterogeneous group of genetically determined muscle disorders. TRAPPC11-related LGMD is an autosomal-recessive condition...
BACKGROUND
Limb-girdle muscular dystrophies (LGMD) are a heterogeneous group of genetically determined muscle disorders. TRAPPC11-related LGMD is an autosomal-recessive condition characterised by muscle weakness and intellectual disability.
METHODS
A clinical and histopathological characterisation of 25 Roma individuals with LGMD R18 caused by the homozygous c.1287+5G>A variant is reported. Functional effects of the variant on mitochondrial function were investigated.
RESULTS
The c.1287+5G>A variant leads to a phenotype characterised by early onset muscle weakness, movement disorder, intellectual disability and elevated serum creatine kinase, which is similar to other series. As novel clinical findings, we found that microcephaly is almost universal and that infections in the first years of life seem to act as triggers for a psychomotor regression and onset of seizures in several individuals with variants, who showed pseudometabolic crises triggered by infections. Our functional studies expanded the role of TRAPPC11 deficiency in mitochondrial function, as a decreased mitochondrial ATP production capacity and alterations in the mitochondrial network architecture were detected.
CONCLUSION
We provide a comprehensive phenotypic characterisation of the pathogenic variant c.1287+5G>A, which is founder in the Roma population. Our observations indicate that some typical features of golgipathies, such as microcephaly and clinical decompensation associated with infections, are prevalent in individuals with LGMD R18.
Topics: Humans; Microcephaly; Intellectual Disability; Roma; Phenotype; Muscular Dystrophies; Muscular Dystrophies, Limb-Girdle; Muscle Weakness; Vesicular Transport Proteins
PubMed: 37197784
DOI: 10.1136/jmg-2022-109132 -
Journal of Inherited Metabolic Disease Feb 2024The balance between a protective and a destructive immune response can be precarious, as exemplified by inborn errors in nucleotide metabolism. This class of inherited...
The balance between a protective and a destructive immune response can be precarious, as exemplified by inborn errors in nucleotide metabolism. This class of inherited disorders, which mimics infection, can result in systemic injury and severe neurologic outcomes. The most common of these disorders is Aicardi Goutières syndrome (AGS). AGS results in a phenotype similar to "TORCH" infections (Toxoplasma gondii, Other [Zika virus (ZIKV), human immunodeficiency virus (HIV)], Rubella virus, human Cytomegalovirus [HCMV], and Herpesviruses), but with sustained inflammation and ongoing potential for complications. AGS was first described in the early 1980s as familial clusters of "TORCH" infections, with severe neurology impairment, microcephaly, and basal ganglia calcifications (Aicardi & Goutières, Ann Neurol, 1984;15:49-54) and was associated with chronic cerebrospinal fluid (CSF) lymphocytosis and elevated type I interferon levels (Goutières et al., Ann Neurol, 1998;44:900-907). Since its first description, the clinical spectrum of AGS has dramatically expanded from the initial cohorts of children with severe impairment to including individuals with average intelligence and mild spastic paraparesis. This broad spectrum of potential clinical manifestations can result in a delayed diagnosis, which families cite as a major stressor. Additionally, a timely diagnosis is increasingly critical with emerging therapies targeting the interferon signaling pathway. Despite the many gains in understanding about AGS, there are still many gaps in our understanding of the cell-type drivers of pathology and characterization of modifying variables that influence clinical outcomes and achievement of timely diagnosis.
PubMed: 38421058
DOI: 10.1002/jimd.12721 -
Emerging Microbes & Infections Dec 2024Mosquito-borne viral infections are on the rise worldwide and can lead to severe symptoms such as haemorrhage, encephalitis, arthritis or microcephaly. A protective... (Review)
Review
Mosquito-borne viral infections are on the rise worldwide and can lead to severe symptoms such as haemorrhage, encephalitis, arthritis or microcephaly. A protective immune response following mosquito-borne viral infections requires the generation of a controlled and balanced immune response leading to viral clearance without immunopathology. Here, regulatory T cells play a central role in restoring immune homeostasis. In current review, we aim to provide an overview and summary of the phenotypes of FOXP3 Tregs in various mosquito-borne arboviral disease, their association with disease severity and their functional characteristics. Furthermore, we discuss the role of cytokines and Tregs in the immunopathogenesis of mosquito-borne infections. Lastly, we discuss possible novel lines of research which could provide additional insight into the role of Tregs in mosquito-borne viral infections in order to develop novel therapeutic approaches or vaccination strategies.
Topics: Animals; Humans; Culicidae; T-Lymphocytes, Regulatory; Virus Diseases; Encephalitis; Microcephaly; Arboviruses; Mosquito Vectors; Arbovirus Infections
PubMed: 38192073
DOI: 10.1080/22221751.2024.2304061 -
Brain : a Journal of Neurology Jan 2024Highly conserved transport protein particle (TRAPP) complexes regulate subcellular trafficking pathways. Accurate protein trafficking has been increasingly recognized to...
Highly conserved transport protein particle (TRAPP) complexes regulate subcellular trafficking pathways. Accurate protein trafficking has been increasingly recognized to be critically important for normal development, particularly in the nervous system. Variants in most TRAPP complex subunits have been found to lead to neurodevelopmental disorders with diverse but overlapping phenotypes. We expand on limited prior reports on TRAPPC6B with detailed clinical and neuroradiologic assessments, and studies on mechanisms of disease, and new types of variants. We describe 29 additional patients from 18 independent families with biallelic variants in TRAPPC6B. We identified seven homozygous nonsense (n = 12 patients) and eight canonical splice-site variants (n = 17 patients). In addition, we identified one patient with compound heterozygous splice-site/missense variants with a milder phenotype and one patient with homozygous missense variants. Patients displayed non-progressive microcephaly, global developmental delay/intellectual disability, epilepsy and absent expressive language. Movement disorders including stereotypies, spasticity and dystonia were also observed. Brain imaging revealed reductions in cortex, cerebellum and corpus callosum size with frequent white matter hyperintensity. Volumetric measurements indicated globally diminished volume rather than specific regional losses. We identified a reduced rate of trafficking into the Golgi apparatus and Golgi fragmentation in patient-derived fibroblasts that was rescued by wild-type TRAPPC6B. Molecular studies revealed a weakened interaction between mutant TRAPPC6B (c.454C>T, p.Q152*) and its TRAPP binding partner TRAPPC3. Patient-derived fibroblasts from the TRAPPC6B (c.454C>T, p.Q152*) variant displayed reduced levels of TRAPPC6B as well as other TRAPP II complex-specific members (TRAPPC9 and TRAPPC10). Interestingly, the levels of the TRAPPC6B homologue TRAPPC6A were found to be elevated. Moreover, co-immunoprecipitation experiments showed that TRAPPC6A co-precipitates equally with TRAPP II and TRAPP III, while TRAPPC6B co-precipitates significantly more with TRAPP II, suggesting enrichment of the protein in the TRAPP II complex. This implies that variants in TRAPPC6B may preferentially affect TRAPP II functions compared to TRAPP III functions. Finally, we assessed phenotypes in a Drosophila TRAPPC6B-deficiency model. Neuronal TRAPPC6B knockdown impaired locomotion and led to wing posture defects, supporting a role for TRAPPC6B in neuromotor function. Our findings confirm the association of damaging biallelic TRAPPC6B variants with microcephaly, intellectual disability, language impairments, and epilepsy. A subset of patients also exhibited dystonia and/or spasticity with impaired ambulation. These features overlap with disorders arising from pathogenic variants in other TRAPP subunits, particularly components of the TRAPP II complex. These findings suggest that TRAPPC6B is essential for brain development and function, and TRAPP II complex activity may be particularly relevant for mediating this function.
Topics: Animals; Humans; Microcephaly; Intellectual Disability; Vesicular Transport Proteins; Dystonia; Neurodevelopmental Disorders; Epilepsy
PubMed: 37713627
DOI: 10.1093/brain/awad301 -
Experimental Cell Research Mar 2024Kinesin motors play a fundamental role in development by controlling intracellular transport, spindle assembly, and microtubule organization. In humans, patients...
Kinesin motors play a fundamental role in development by controlling intracellular transport, spindle assembly, and microtubule organization. In humans, patients carrying mutations in KIF11 suffer from an autosomal dominant inheritable disease called microcephaly with or without chorioretinopathy, lymphoedema, or mental retardation (MCLMR). While mitotic functions of KIF11 proteins have been well documented in centrosome separation and spindle assembly, cellular mechanisms underlying KIF11 dysfunction and MCLMR remain unclear. In this study, we generate KIF11-inhibition chick and zebrafish models and find that KIF11 inhibition results in microcephaly, chorioretinopathy, and severe developmental defects in vivo. Notably, loss-of-function of KIF11 causes the formation of monopolar spindle and chromosome misalignment, which finally contribute to cell cycle arrest, chromosome instability, and cell death. Our results demonstrate that KIF11 is crucial for spindle assembly, chromosome alignment, and cell cycle progression of progenitor stem cells, indicating a potential link between polyploidy and MCLMR. Our data have revealed that KIF11 inhibition cause microcephaly, chorioretinopathy, and development disorders through the formation of monopolar spindle, polyploid, and cell cycle arrest.
Topics: Animals; Cell Cycle Checkpoints; Chromosomal Instability; Developmental Disabilities; Facies; Kinesins; Lymphedema; Microcephaly; Phenotype; Retinal Diseases; Retinal Dysplasia; Zebrafish
PubMed: 38367657
DOI: 10.1016/j.yexcr.2024.113975 -
CNS Neuroscience & Therapeutics Dec 2023Christianson syndrome (CS) is caused by mutations in SLC9A6 and is characterized by global developmental delay, epilepsy, hyperkinesis, ataxia, microcephaly, and...
BACKGROUND
Christianson syndrome (CS) is caused by mutations in SLC9A6 and is characterized by global developmental delay, epilepsy, hyperkinesis, ataxia, microcephaly, and behavioral disorder. However, the molecular mechanism by which these SLC9A6 mutations cause CS in humans is not entirely understood, and there is no objective method to determine the pathogenicity of single SLC9A6 variants.
METHODS
Trio-based whole exome sequencing (WES) was carried out on two individuals with suspicion of CS. qRT-PCR, western blot analysis, filipin staining, lysosomal enzymatic assays, and electron microscopy examination, using EBV-LCLs established from the two patients, were performed.
RESULTS
Trio-based WES identified a hemizygous SLC9A6 c.1560dupT, p.T521Yfs*23 variant in proband 1 and a hemizygous SLC9A6 c.608delA, p.H203Lfs*10 variant in proband 2. Both children exhibited typical phenotypes associated with CS. Expression analysis in EBV-LCLs derived from the two patients showed a significant decrease in mRNA levels and no detectable normal NHE6 protein. EBV-LCLs showed a statistically significant increase in unesterified cholesterol in patient 1, but only non-significant increase in patient 2 when stained with filipin. Activities of lysosomal enzymes (β-hexosaminidase A, β-hexosaminidase A + B, β-galactosidase, galactocerebrosidase, arylsulfatase A) of EBV-LCLs did not significantly differ between the two patients and six controls. Importantly, by electron microscopy we detected an accumulation of lamellated membrane structures, deformed mitochondria, and lipid droplets in the patients' EBV-LCLs.
CONCLUSIONS
The SLC9A6 p.T521Yfs*23 and p.H203Lfs*10 variants in our patients result in loss of NHE6. Alterations of mitochondria and lipid metabolism may play a role in the pathogenesis of CS. Moreover, the combination of filipin staining with electron microscopy examination of patient lymphoblastoid cells can serve as a useful complementary diagnostic method for CS.
Topics: Child; Humans; Ataxia; beta-N-Acetylhexosaminidases; Epilepsy; Filipin; Microcephaly
PubMed: 37381736
DOI: 10.1111/cns.14329 -
Genes Nov 2023Pathogenic gene variants encoding nuclear pore complex (NPC) proteins were previously implicated in the pathogenesis of steroid-resistant nephrotic syndrome (SRNS). The... (Review)
Review
Pathogenic gene variants encoding nuclear pore complex (NPC) proteins were previously implicated in the pathogenesis of steroid-resistant nephrotic syndrome (SRNS). The gene, encoding nucleoporin, is related to a very rare form of SRNS with limited genotype-phenotype information. We identified an Italian boy affected with an SRNS associated with severe neurodevelopmental impairment characterized by microcephaly, axial hypotonia, lack of achievement of motor milestones, and refractory seizures with an associated hypsarrhythmic pattern on electroencephalography. Brain magnetic resonance imaging (MRI) showed hypoplasia of the corpus callosum and a simplified gyration of the cerebral cortex. Since the age of 3 years, the boy was followed up at our Pediatric Nephrology Department for an SRNS, with a focal segmental glomerulosclerosis at renal biopsy. The boy died 32 months after SRNS onset, and a Whole-Exome Sequencing analysis revealed a novel compound heterozygous variant in (NM_024844.5): 611T>A (p.Val204Glu), c.1904T>G (p.Leu635Arg), inherited from the father and mother, respectively. We delineated the clinical phenotypes of NUP85-related disorders, reviewed the affected individuals so far reported in the literature, and overall expanded both the phenotypic and the molecular spectrum associated with this ultra-rare genetic condition. Our study suggests a potential occurrence of severe neurological phenotypes as part of the -related clinical spectrum and highlights an important involvement of nucleoporin in brain developmental processes and neurological function.
Topics: Child; Child, Preschool; Humans; Male; Mutation; Nephrotic Syndrome; Neurons; Nuclear Pore Complex Proteins; Podocytes
PubMed: 38136965
DOI: 10.3390/genes14122143 -
Frontiers in Immunology 2023Non-WNT/non-SHH medulloblastoma (MB) is one of the subtypes with the highest genetic heterogeneity in MB, and its current treatment strategies have unsatisfactory...
BACKGROUND
Non-WNT/non-SHH medulloblastoma (MB) is one of the subtypes with the highest genetic heterogeneity in MB, and its current treatment strategies have unsatisfactory results and significant side effects. As a member of the centromere protein (CENP) family, centromeric protein E (CENPE) is a microtubule plus-end-directed kinetochore protein. Heterozygous mutations in CENPE can leads to primary microcephaly syndrome. It has been reported that CENPE is upregulated in MB, but its role in MB development is still unknown.
METHODS
We downloaded the relevant RNA seq data and matched clinical information from the GEO database. Bioinformatics analysis includes differential gene expression analysis, Kaplan-Meier survival analysis, nomogram analysis, ROC curve analysis, immune cell infiltration analysis, and gene function enrichment analysis. Moreover, the effects of CENPE expression on cell proliferation, cell cycle, and p53 signaling pathway of non-WNT/non-SHH MB were validated using CENPE specific siRNA experiments.
RESULTS
Compared with normal tissues, CENPE was highly expressed in MB tissues and served as an independent prognostic factor for survival in non-WNT/non-SHH MB patients. The nomogram analysis and ROC curve further confirmed these findings. At the same time, immune cell infiltration analysis showed that CENPE may participate in the immune response and tumor microenvironment (TME) of non-WNT/non-SHH MB. In addition, gene enrichment analysis showed that CENPE was closely related to the cell cycle and p53 pathway in non-WNT/non-SHH MB. experimental validation showed that knockdown of CENPE inhibited cell proliferation by activating the p53 signaling pathway and blocking the cell cycle.
CONCLUSION
The expression of CENPE in non-WNT/non-SHH MB was positively correlated with poor prognosis. CENPE may affect tumor progression by regulating cell cycle, p53 pathway, and immune infiltration. Hence, CENPE is highly likely a novel biomarker and potential therapeutic target for non-WNT/non-SHH MB.
Topics: Humans; Medulloblastoma; Microcephaly; Tumor Suppressor Protein p53; Biomarkers; Cerebellar Neoplasms; Tumor Microenvironment
PubMed: 37593739
DOI: 10.3389/fimmu.2023.1227143 -
Pediatric Neurology Oct 2023TANGO2 deficiency disorder is a rare genetic disease caused by biallelic defects in TANGO2 gene.
BACKGROUND
TANGO2 deficiency disorder is a rare genetic disease caused by biallelic defects in TANGO2 gene.
METHODS
We report the clinical phenotype of two children with TANGO2 deficiency disorder.
RESULTS
Patient 1 is a female child presenting with developmental delay and microcephaly during the second year of life, who evolved with severe cognitive impairment, facial dysmorphisms, spastic paraparesis, and atonic seizures. At age 13 years, she was hospitalized due to an episode of rhabdomyolysis complicated with cardiac arrhythmia and hypothyroidism. Patient 2 is a female child with dysmorphic facial features, cleft palate, and developmental delay who was diagnosed with DiGeorge syndrome. At age three years, she presented with an acute episode of severe rhabdomyolysis in the context of human herpesvirus 6 infection. After the resolution of this acute episode, she maintained recurrent muscle weakness with axial hypotonia and progressive spasticity of the lower extremities. In both patients, diagnosis of TANGO2 deficiency disorder was only confirmed after an acute metabolic crisis.
CONCLUSIONS
A high index of suspicion for TANGO2 deficiency disorder is needed in patients with developmental delay or other neurological symptoms and episodic rhabdomyolysis.
Topics: Child; Humans; Female; Adolescent; Child, Preschool; Microcephaly; Seizures; Phenotype; DiGeorge Syndrome; Rhabdomyolysis
PubMed: 37562170
DOI: 10.1016/j.pediatrneurol.2023.07.010 -
Pediatric Research Mar 2024Pregnant individuals with viral illness may experience significant morbidity and have higher rates of pregnancy and neonatal complications. With the growing number of... (Review)
Review
Pregnant individuals with viral illness may experience significant morbidity and have higher rates of pregnancy and neonatal complications. With the growing number of viral infections and new viral pandemics, it is important to examine the effects of infection during pregnancy on both the gestational parent and the offspring. Febrile illness and inflammation during pregnancy are correlated with risk for autism, attention deficit/hyperactivity disorder, and developmental delay in the offspring in human and animal models. Historical viral epidemics had limited follow-up of the offspring of affected pregnancies. Infants exposed to seasonal influenza and the 2009 H1N1 influenza virus experienced increased risks of congenital malformations and neuropsychiatric conditions. Zika virus exposure in utero can lead to a spectrum of abnormalities, ranging from severe microcephaly to neurodevelopmental delays which may appear later in childhood and in the absence of Zika-related birth defects. Vertical infection with severe acute respiratory syndrome coronavirus-2 has occurred rarely, but there appears to be a risk for developmental delays in the infants with antenatal exposure. Determining how illness from infection during pregnancy and specific viral pathogens can affect pregnancy and neurodevelopmental outcomes of offspring can better prepare the community to care for these children as they grow. IMPACT: Viral infections have impacted pregnant people and their offspring throughout history. Antenatal exposure to maternal fever and inflammation may increase risk of developmental and neurobehavioral disorders in infants and children. The recent SARS-CoV-2 pandemic stresses the importance of longitudinal studies to follow pregnancies and offspring neurodevelopment.
PubMed: 38509227
DOI: 10.1038/s41390-024-03145-z