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SRY-box transcription factor (SOX) genes, a recently discovered gene family, play crucial roles in the regulation of neuronal stem cell proliferation and glial differentiation during nervous system development and neurogenesis. Whole exome sequencing (WES) in patients presenting with generalized epilepsy, intellectual disability, and childhood emotional behavioral disorder, uncovered a de novo variation within SOX12 gene. Notably, this gene has never been associated with neurodevelopmental disorders. No variants in known genes linked with the patient's symptoms have been detected by the WES Trio analysis. To date, any MIM phenotype number associated with intellectual developmental disorder has not been assigned for SOX12. In contrast, both SOX4 and SOX11 genes within the same C group (SoxC) of the Sox gene family have been associated with neurodevelopmental disorders. The variant identified in the patient here described was situated within the critical high-mobility group (HMG) functional site of the SOX12 protein. This domain, in the Sox protein family, is essential for DNA binding and bending, as well as being responsible for transcriptional activation or repression during the early stages of gene expression. Sequence alignment within SoxC (SOX12, SOX4 and SOX11) revealed a high conservation rate of the HMG region. The in silico predictive analysis described this novel variant as likely pathogenic. Furthermore, the mutated protein structure predictions unveiled notable changes with potential deleterious effects on the protein structure. The aim of this study is to establish a correlation between the SOX12 gene and the symptoms diagnosed in the patient.
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Ion channelopathies result from impaired ion channel protein function, due to mutations affecting ion transport across cell membranes. Over 40 diseases, including neuropathy, pain, migraine, epilepsy, and ataxia, are associated with ion channelopathies, impacting electrically excitable tissues and significantly affecting skeletal muscle. Gene mutations affecting transmembrane ionic flow are strongly linked to skeletal muscle disorders, particularly myopathies, disrupting muscle excitability and contraction. Electromyography (EMG) analysis performed on a patient who complained of weakness and fatigue revealed the presence of primary muscular damage, suggesting an early-stage myopathy. Whole exome sequencing (WES) did not detect potentially causative variants in known myopathy-associated genes but revealed a novel homozygous deletion of the P2RX6 gene likely disrupting protein function. The P2RX6 gene, predominantly expressed in skeletal muscle, is an ATP-gated ion channel receptor belonging to the purinergic receptors (P2RX) family. In addition, STRING pathways suggested a correlation with more proteins having a plausible role in myopathy. No previous studies have reported the implication of this gene in myopathy. Further studies are needed on patients with a defective ion channel pathway, and the use of in vitro functional assays in suppressing P2RX6 gene expression will be required to validate its functional role.
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Developmental and epileptic encephalopathies (DEE) are severe neurodevelopmental disorders characterized by recurrent, usually early-onset, epileptic seizures accompanied by developmental impairment often related to both underlying genetic etiology and abnormal epileptiform activity. Today, next-generation sequencing technologies (NGS) allow us to sequence large portions of DNA quickly and with low costs. The aim of this study is to evaluate the use of whole-exome sequencing (WES) as a first-line molecular genetic test in a sample of subjects with DEEs characterized by early-onset drug-resistant epilepsies, associated with global developmental delay and/or intellectual disability (ID). We performed 82 WESs, identifying 35 pathogenic variants with a detection rate of 43%. The identified variants were highlighted on 29 different genes including, 3 new candidate genes (KCNC2, STXBP6, DHRS9) for DEEs never identified before. In total, 23 out of 35 (66%) de novo variants were identified. The most frequently identified type of inheritance was autosomal dominant de novo (60%) followed by autosomal recessive in homozygosity (17%) and heterozygosity (11%), autosomal dominant inherited from parental mosaicism (6%) and X-linked dominant de novo (6%). The most frequent mutations identified were missense (75%) followed by frameshift deletions (16%), frameshift duplications (5%), and splicing mutations (3%). Considering the results obtained in the present study we support the use of WES as a form of first-line molecular genetic testing in DEEs.
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Epilepsia Generalizada , Transtornos do Neurodesenvolvimento , Humanos , Sequenciamento do Exoma , Mosaicismo , Biologia Molecular , Canais de Potássio ShawRESUMO
Syntaxin-binding protein 6 (STXBP6), also known as amysin, is an essential component of the SNAP receptor (SNARE) complex and plays a crucial role in neuronal vesicle trafficking. Mutations in genes encoding SNARE proteins are often associated with a broad spectrum of neurological conditions defined as "SNAREopathies", including epilepsy, intellectual disability, and neurodevelopmental disorders such as autism spectrum disorders. The present whole exome sequencing (WES) study describes, for the first time, the occurrence of developmental epileptic encephalopathy and autism spectrum disorders as a result of a de novo deletion within the STXBP6 gene. The truncated protein in the STXBP6 gene leading to a premature stop codon could negatively modulate the synaptic vesicles' exocytosis. Our research aimed to elucidate a plausible, robust correlation between STXBP6 gene deletion and the manifestation of developmental epileptic encephalopathy.
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Epilepsia Generalizada , Epilepsia , Transtornos do Neurodesenvolvimento , Humanos , Epilepsia/genética , Mutação , Transtornos do Neurodesenvolvimento/genética , Códon sem Sentido , Proteínas de Transporte/genéticaRESUMO
Background and Objectives: Specific Learning Disorder (SLD) is a complex neurobiological disorder characterized by a persistent difficult in reading (dyslexia), written expression (dysgraphia), and mathematics (dyscalculia). The hereditary and genetic component is one of the underlying causes of SLD, but the relationship between genes and the environment should be considered. Several genetic studies were performed in different populations to identify causative genes. Materials and Methods: Here, we show the analysis of 9 multiplex families with at least 2 individuals diagnosed with SLD per family, with a total of 37 persons, 21 of whom are young subjects with SLD, by means of Next-Generation Sequencing (NGS) to identify possible causative mutations in a panel of 15 candidate genes: CCPG1, CYP19A1, DCDC2, DGKI, DIP2A, DYM, GCFC2, KIAA0319, MC5R, MRPL19, NEDD4L, PCNT, PRMT2, ROBO1, and S100B. Results: We detected, in eight families out nine, SNP variants in the DGKI, DIP2A, KIAA0319, and PCNT genes, even if in silico analysis did not show any causative effect on this behavioral condition. In all cases, the mutation was transmitted by one of the two parents, thus excluding the case of de novo mutation. Moreover, the parent carrying the allelic variant transmitted to the children, in six out of seven families, reports language difficulties. Conclusions: Although the present results cannot be considered conclusive due to the limited sample size, the identification of genetic variants in the above genes can provide input for further research on the same, as well as on other genes/mutations, to better understand the genetic basis of this disorder, and from this perspective, to better understand also the neuropsychological and social aspects connected to this disorder, which affects an increasing number of young people.
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Transtorno de Aprendizagem Específico , Criança , Humanos , Adolescente , Proteínas do Tecido Nervoso , Receptores Imunológicos , Alelos , Sequenciamento de Nucleotídeos em Larga Escala , Proteínas Associadas aos MicrotúbulosRESUMO
During the first wave of COVID-19 infection in Italy, the number of cases and the mortality rates were among the highest compared to the rest of Europe and the world. Several studies demonstrated a severe clinical course of COVID-19 associated with old age, comorbidities, and male gender. However, there are cases of virus infection resistance in subjects living in close contact with infected subjects. Thus, to explain the predisposition to virus infection and to COVID-19 disease progression, we must consider, in addition to the genetic variability of the virus and other environmental or comorbidity conditions, the allelic variants of specific human genes, directly or indirectly related to the life cycle of the virus. Here, we analyzed three human genetic polymorphisms belonging to the TMPRSS2 and CCR5 genes in a sample population from Sicily (Italy) to investigate possible correlations with the resistance to viral infection and/or to COVID-19 disease progression as recently described in other human populations. Our results did not show any correlations of the rs35074065, rs12329760, and rs333 polymorphisms with SARS-CoV-2 infection or with COVID-19 disease severity. Further studies on other human genetic polymorphisms should be performed to identify the major human determinants of SARS-CoV-2 viral resistance.
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COVID-19 , Receptores CCR5 , SARS-CoV-2 , Serina Endopeptidases , COVID-19/genética , Progressão da Doença , Predisposição Genética para Doença , Humanos , Receptores CCR5/genética , Serina Endopeptidases/genética , SicíliaRESUMO
PHF21A (PHD finger protein 21A) gene, located in the short arm of chromosome 11, encodes for BHC80, a component of the Lysine Specific Demethylase 1, Corepressor of REST (LSD1-CoREST) complex. BHC80 is mainly expressed in the human fetal brain and skeletal muscle and acts as a modulator of several neuronal genes during embryogenesis. Data from literature relates PHF21A variants with Potocki-Shaffer Syndrome (PSS), a contiguous gene deletion disorder caused by the haploinsufficiency of PHF21A, ALX4, and EXT2 genes. Clinical cardinal features of PSS syndrome are multiple exostoses (due to the EXT2 involvement), biparietal foramina (due to the ALX4 involvement), intellectual disability, and craniofacial anomalies (due to the PHF21A involvement). To date, to the best of our knowledge, a detailed description of PHF21A-related disorder clinical phenotype is not described in the literature; in fact, only 14 subjects with microdeletion frameshift or nonsense variants concerning only PHF21A gene have been reported. All reported cases did not present ALX4 or EXT2 variants, and their clinical features did not fit with PSS diagnosis. Herein, by using Exome sequencing, and Sanger sequencing of the region of interest, we describe a case of a child with a paternally inherited (mosaicism of 5%) truncating variant of the PHF21A gene (c.649_650del; p.Gln217ValfsTer6), and discuss the new evidence. In conclusion, these patients showed varied clinical expressions, mainly including the presence of intellectual disability, epilepsy, hypotonia, and dysmorphic features. Our study contributes to describing the genotype-phenotype spectrum of patients with PHF21A-related disorder; however, the limited data in the literature have been unable to provide a precise diagnostic protocol for patients with PHF21A-related disorder.
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Transtornos Cromossômicos , Deficiência Intelectual , Criança , Humanos , Deficiência Intelectual/genética , Deleção Cromossômica , Transtornos Cromossômicos/genética , Deleção de Genes , Fenótipo , Histona Desacetilases/genéticaRESUMO
BACKGROUND: Genetic familiar causes of oro-facial dyskinesia are usually restricted to Huntington's disease, whereas other causes are often missed or underestimated. Here, we report the case of late-onset oro-facial dyskinesia in an elderly patient with a genetic diagnosis of Spinocerebellar Ataxia type 2 (SCA2). CASE PRESENTATION: A 75-year-old man complained of progressive balance difficulty since the age of 60 years, associated with involuntary movements of the mouth and tongue over the last 3 months. No exposure to anti-dopaminergic agents, other neuroleptics, antidepressants, or other drugs was reported. Family history was positive for SCA2 (brother and the son of the brother). At rest, involuntary movements of the mouth and tongue were noted; they appeared partially suppressible and became more evident during stress and voluntary movements. Cognitive examination revealed frontal-executive dysfunction, memory impairment, and attention deficit. Brain magnetic resonance imaging (MRI) disclosed signs of posterior periventricular chronic cerebrovascular disease and a marked ponto-cerebellar atrophy, as confirmed by volumetric MRI analysis. A dopamine transporter imaging scan demonstrated a bilaterally reduced putamen and caudate nucleus uptake. Ataxin-2 (ATXN2) gene analysis revealed a 36 cytosine-adenine-guanine (CAG) repeat expansion, confirming the diagnosis of SCA2. CONCLUSIONS: SCA2 should be considered among the possible causes of adult-onset oro-facial dyskinesia, especially when the family history suggests an inherited cerebellar disorder. Additional clinical features, including parkinsonism and motor neuron disease, may represent relevant cues for an early diagnosis and adequate management.
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Proteínas da Membrana Plasmática de Transporte de Dopamina/metabolismo , Transtornos Parkinsonianos/fisiopatologia , Ataxias Espinocerebelares/genética , Idoso , Cerebelo/patologia , Humanos , Imageamento por Ressonância Magnética , Masculino , Ponte/patologiaRESUMO
We sequenced the genomes of a â¼7,000-year-old farmer from Germany and eight â¼8,000-year-old hunter-gatherers from Luxembourg and Sweden. We analysed these and other ancient genomes with 2,345 contemporary humans to show that most present-day Europeans derive from at least three highly differentiated populations: west European hunter-gatherers, who contributed ancestry to all Europeans but not to Near Easterners; ancient north Eurasians related to Upper Palaeolithic Siberians, who contributed to both Europeans and Near Easterners; and early European farmers, who were mainly of Near Eastern origin but also harboured west European hunter-gatherer related ancestry. We model these populations' deep relationships and show that early European farmers had â¼44% ancestry from a 'basal Eurasian' population that split before the diversification of other non-African lineages.
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Genoma Humano/genética , População Branca/classificação , População Branca/genética , Agricultura/história , Ásia/etnologia , Europa (Continente) , História Antiga , Humanos , Dinâmica Populacional , Análise de Componente Principal , Recursos HumanosRESUMO
Spinal muscular atrophy (SMA) refers to a group of genetic neuromuscular disorders affecting lower motor neurons causative of numerous phenotypes. To date, according to the age of onset, maximum muscular activity achieved, and life expectation four types of SMA are recognized, all caused by mutations in the SMN1 gene with SMN2 copy number influencing disease severity. Herein, we describe the case of a 31-year-old young male with normal psychomotor development who has experienced fatigue, cramps, and muscle fasciculations in the lower limbs for a period of 2 months. Based on electrophysiological and clinical findings we performed SMA genetic, clinical exome and RNA expression of candidate genes which led us to suggest SMN1-SMN2 genes [(2+0) and (0+0)] combination as possibly being implicated in the phenotype.
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Atrofia Muscular Espinal/genética , Proteína 1 de Sobrevivência do Neurônio Motor/genética , Adulto , Eletromiografia , Genótipo , Humanos , Masculino , Mutação , Proteína 2 de Sobrevivência do Neurônio Motor/economiaRESUMO
Purpose: The advancements in the next-generation sequencing (NGS) techniques have allowed for rapid, efficient, and cost-time-effective genetic variant detection. However, in both clinical practice and research setting, sequencing is still often limited to the use of gene panels clinically targeted on the genes underlying the disease of interest. Methods: We performed a neurogenetic study through an ad hoc NGS-based custom sequencing gene panel in order to screen 16 genes in 8 patients with different types of degenerative cognitive disorders (Alzheimer's disease, mild cognitive impairment, frontotemporal dementia, and dementia associated with Parkinson's disease). The study protocol was based on previous evidence showing a high sensitivity and specificity of the technique even when the panel is limited to some hotspot exons. Results: We found variants of the TREM2 and APP genes in three patients; these have been previously identified as pathogenic or likely pathogenic and, therefore, considered "disease causing." In the remaining subjects, the pathogenicity was evaluated according to the guidelines of the American College of Medical Genetics (ACMG). In one patient, the p.R205W variant in the CHMP2B gene was found to be likely pathogenic of the disease. A variant in the CSF1R and SERPINI1 genes found in two patients was classified as benign, whereas the other two (in the GRN and APP genes) were classified as likely pathogenic according to the ACMG. Conclusions: Notwithstanding the preliminary value of this study, some rare genetic variants with a probable disease association were detected. Although future application of NGS-based sensors and further replication of these experimental data are needed, this approach seems to offer promising translational perspectives in the diagnosis and management of a wide range of neurodegenerative disorders.
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Demência/genética , Variação Genética , Sequenciamento de Nucleotídeos em Larga Escala/métodos , Adulto , Idoso , Idoso de 80 Anos ou mais , Precursor de Proteína beta-Amiloide/genética , Feminino , Humanos , Masculino , Glicoproteínas de Membrana/genética , Projetos Piloto , Receptores Imunológicos/genéticaRESUMO
We report a 6-year-old girl showing epidermolytic ichthyosis/epidermolytic hyperkeratosis (EI/EH). Targeted Next Generation Sequencing revealed a de novo, previously unidentified KRT1 mutation. The findings of this study expands the clinical and spectrum and genotype-phenotype correlation associated with EI/EH.
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Hiperceratose Epidermolítica/genética , Queratina-1/genética , Ceratodermia Palmar e Plantar Epidermolítica/genética , Mutação , Criança , Feminino , Pé/patologia , Mãos/patologia , Sequenciamento de Nucleotídeos em Larga Escala , Humanos , Hiperceratose Epidermolítica/patologia , Ceratodermia Palmar e Plantar Epidermolítica/patologiaRESUMO
The DHRS9 gene is involved in several pathways including the synthesis of allopregnanolone from progesterone. Allopregnanolone is a positive modulator of gamma aminobutyric acid (GABA) action and plays a role in the control of neuronal excitability and seizures. Whole-exome sequencing performed on a girl with an early onset epilepsy revealed that she was a compound heterozygote for two novel missense mutations of the DHRS9 gene likely to disrupt protein function. No previous studies have reported the implication of this gene in epilepsy. We discuss a new potential pathogenic mechanism underlying epilepsy in a child, due to a defective progesterone pathway.
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3-Hidroxiesteroide Desidrogenases/análise , Causalidade , Epilepsia/genética , 3-Hidroxiesteroide Desidrogenases/sangue , Pré-Escolar , Epilepsia/diagnóstico , Epilepsia/epidemiologia , Feminino , Humanos , Mutação de Sentido Incorreto/genética , Polimorfismo Genético/genética , Lobo Temporal/anormalidades , Lobo Temporal/diagnóstico por imagemRESUMO
Developmental and epileptic encephalopathies (DEEs) are genetically heterogenous conditions, often characterized by early onset, EEG interictal epileptiform abnormalities, polymorphous and drug-resistant seizures, and neurodevelopmental impairments. In this study, we investigated the genetic defects in two siblings who presented with severe DEE, microcephaly, spastic tetraplegia, diffuse brain hypomyelination, cerebellar atrophy, short stature, and kyphoscoliosis. Whole exome next-generation sequencing (WES) identified in both siblings a homozygous non-sense variant in the ACTL6B gene (NM_016188:c.820C>T;p.Gln274*) coding for a subunit of the neuron-specific chromatin remodeling complex nBAF. To further support these findings, a targeted ACTL6B sequencing assay was performed on a cohort of 85 unrelated DEE individuals, leading to the identification of a homozygous missense variant (NM_016188:c.1045G>A;p.Gly349Ser) in a patient. This variant did not segregate in the unaffected siblings in this family and was classified as deleterious by several prediction softwares. Interestingly, in both families, homozygous patients shared a rather homogeneous phenotype. Very few patients with ACTL6B gene variants have been sporadically reported in WES cohort studies of patients with neurodevelopmental disorders and/or congenital brain malformations. However, the limited number of patients with incomplete clinical information yet reported in the literature did not allow to establish a strong gene-disease association. Here, we provide additional genetic and clinical data on three new cases that support the pathogenic role of ACTL6B gene mutation in a syndromic form of DEE.
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Actinas/genética , Montagem e Desmontagem da Cromatina , Proteínas Cromossômicas não Histona/genética , Proteínas de Ligação a DNA/genética , Doenças Genéticas Inatas/diagnóstico por imagem , Microcefalia/genética , Transtornos do Neurodesenvolvimento/genética , Quadriplegia/genética , Espasmos Infantis/genética , Criança , Pré-Escolar , Cromatina/genética , Metilação de DNA/genética , Feminino , Doenças Genéticas Inatas/genética , Humanos , Lactente , Recém-Nascido , Masculino , Microcefalia/diagnóstico por imagem , Transtornos do Neurodesenvolvimento/diagnóstico por imagem , Linhagem , Quadriplegia/diagnóstico por imagem , Espasmos Infantis/diagnóstico por imagemAssuntos
Ataxia Cerebelar , Humanos , Ataxia Cerebelar/genética , Mutação/genética , Anoctaminas/genéticaRESUMO
BACKGROUND: This study was aimed to investigate the prevalence of dental anxiety in a population of patients with Borderline Intellectual Functioning (BIF) and patients with mild and moderate intellectual disability (ID), and how dental anxiety correlated with their age and gender. METHODS: The sample was made of 700 patients, 287 females and 413 males, 6-to-47 years old, either with borderline intellectual functioning or mild/moderate intellectual disabilities. All patients were administered the Dental Anxiety Scale to assess their level of dental anxiety. RESULTS: Moderate Anxiety was the most prevalent dental anxiety category for patients with intellectual borderline functioning (15.56 %) and mild intellectual disabilities(18.79 %), while Severe Anxiety was the most prevalent category for patients with moderate intellectual disabilities(21 %). Overall, a statistically significant difference (p < 0.001) between the three groups (BIF, Mild-ID and Moderate-ID) was found. Also, the correlation analysis between participants' age and dental anxiety was statistically significant (p < 0.001); indeed, dental anxiety turned out to decrease with the increasing of the age. Moreover, the analysis between gender and dental anxiety was found to be significant as well (p < 0.001), where higher prevalence of dental anxiety was found in females. CONCLUSIONS: To our knowledge, this is the first study on dental anxiety carried out in the field of intellectual disability. Results show that the higher the level of intellectual disability - and consequently the lower the cognitive functioning - the higher the percentage and the severity of dental anxiety.
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Ansiedade ao Tratamento Odontológico , Deficiência Intelectual , Adolescente , Adulto , Criança , Feminino , Humanos , Deficiências da Aprendizagem , Masculino , Pessoa de Meia-Idade , Prevalência , Adulto JovemRESUMO
E3 ubiquitin protein ligase encoded by ARIH2 gene catalyses the ubiquitination of target proteins and plays a crucial role in posttranslational modifications across various cellular processes. As prior documented, mutations in genes involved in the ubiquitination process are often associated with autism spectrum disorder (ASD) and/or intellectual disability (ID). In the current study, a de novo heterozygous mutation was identified in the splicing intronic region adjacent to the last exon of the ARIH2 gene using whole exome sequencing (WES). We hypothesize that this mutation, found in an ASD/ID patient, disrupts the protein Ariadne domain which is involved in the autoinhibition of ARIH2 enzyme. Predictive analyses elucidated the implications of the novel mutation in the splicing process and confirmed its autosomal dominant inheritance model. Nevertheless, we cannot exclude the possibility that other genetic factors, undetectable by WES, such as mutations in non-coding regions and polygenic risk in inter-allelic complementation, may contribute to the patient's phenotype. This work aims to suggest potential relationship between the detected mutation in ARIH2 gene and both ASD and ID, even though functional studies combined with new sequencing approaches will be necessary to validate this hypothesis.
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Transtorno do Espectro Autista , Deficiência Intelectual , Mutação , Ubiquitina-Proteína Ligases , Humanos , Transtorno do Espectro Autista/genética , Deficiência Intelectual/genética , Ubiquitina-Proteína Ligases/genética , Masculino , Sequenciamento do Exoma , Feminino , Predisposição Genética para Doença , CriançaRESUMO
The UNC-5 family of netrin receptor genes, predominantly expressed in brain tissues, plays a pivotal role in various neuronal processes. Mutations in genes involved in axon development contribute to a wide spectrum of human diseases, including developmental, neuropsychiatric, and neurodegenerative disorders. The NTN1/DCC signaling pathway, interacting with UNC5C, plays a crucial role in central nervous system axon guidance and has been associated with psychiatric disorders during adolescence in humans. Whole-exome sequencing analysis unveiled two compound heterozygous causative mutations within the UNC5C gene in a patient diagnosed with psychiatric disorders. In silico analysis demonstrated that neither of the observed variants affected the allosteric linkage between UNC5C and NTN1. In fact, these mutations are located within crucial cytoplasmic domains, specifically ZU5 and the region required for the netrin-mediated axon repulsion of neuronal growth cones. These domains play a critical role in forming the supramodular protein structure and directly interact with microtubules, thereby ensuring the functionality of the axon repulsion process. We emphasize that these mutations disrupt the aforementioned processes, thereby associating the UNC5C gene with psychiatric disorders for the first time and expanding the number of genes related to psychiatric disorders. Further research is required to validate the correlation of the UNC5C gene with psychiatric disorders, but we suggest including it in the genetic analysis of patients with psychiatric disorders.