Developmental outcome of electroencephalographic findings in SYNGAP1 encephalopathy.

SYNGAP1 haploinsufficiency results in a developmental and epileptic encephalopathy (DEE) causing generalized epilepsies accompanied by a spectrum of neurodevelopmental symptoms. Concerning interictal epileptiform discharges (IEDs) in electroencephalograms (EEG), potential biomarkers have been postulated, including changes in background activity, fixation-off sensitivity (FOS) or eye closure sensitivity (ECS). In this study we clinically evaluate a new cohort of 36 SYNGAP1-DEE individuals. Standardized questionnaires were employed to collect clinical, electroencephalographic and genetic data. We investigated electroencephalographic findings, focusing on the cortical distribution of interictal abnormalities and their changes with age. Among the 36 SYNGAP1-DEE cases 18 presented variants in the SYNGAP1 gene that had never been previously reported. The mean age of diagnosis was 8 years and 8 months, ranging from 2 to 17 years, with 55.9% being male. All subjects had global neurodevelopmental/language delay and behavioral abnormalities; 83.3% had moderate to profound intellectual disability (ID), 91.7% displayed autistic traits, 73% experienced sleep disorders and 86.1% suffered from epileptic seizures, mainly eyelid myoclonia with absences (55.3%). A total of 63 VEEGs were revised, observing a worsening of certain EEG findings with increasing age. A disorganized background was observed in all age ranges, yet this was more common among older cases. The main IEDs were bilateral synchronous and asynchronous posterior discharges, accounting for ≥50% in all age ranges. Generalized alterations with maximum amplitude in the anterior region showed as the second most frequent IED (≥15% in all age ranges) and were also more common with increasing age. Finally, diffuse fast activity was much more prevalent in cases with 6 years or older. To the best of our knowledge, this is the first study to analyze EEG features across different age groups, revealing an increase in interictal abnormalities over infancy and adolescence. Our findings suggest that SYNGAP1 haploinsufficiency has complex effects in human brain development, some of which might unravel at different developmental stages. Furthermore, they highlight the potential of baseline EEG to identify candidate biomarkers and the importance of natural history studies to develop specialized therapies and clinical trials.

[Genetics of ADHD in clinical practice]. / Genética del TDAH en la práctica clínica.

Attention-deficit/hyperactivity disorder (ADHD) is a complex and heterogeneous neurodevelopmental disorder from a causal, clinical and prognostic perspective. Research reflects its multifactorial nature with a prominent role of genetic factors. Population studies have historically pointed to the involvement of numerous genetic variants of small effect size, which hardly by themselves increase the risk of presenting the disorder and hardly justify its high heritability. Many of them are present in more than 60% of the general population, suggesting their modulatory rather than causal role. However, after the irruption of new genetic techniques in the last 15 years, a greater number of cases are being identified with genetic disorders (many of them monogenic), whose genetic variants alone explain the presence of ADHD. A detailed study of the personal and family history, as well as a complete physical examination, can help to identify some of them. The identification of the cause in this group of cases has a crucial value in clinical counseling, genetic-familial counseling and prognostic anticipation, as well as in the performance or avoidance of complementary studies and in the design of the intervention plan.

El trastorno por déficit de atención/hiperactividad (TDAH) es un trastorno del neurodesarrollo complejo y heterogéneo desde una perspectiva causal, clínica y pronóstica. La investigación refleja su carácter multifactorial con un papel destacado de los factores genéticos. Los estudios poblacionales han señalado históricamente la implicación de numerosas variantes genéticas de escaso tamaño de efecto, las cuales por sí mismas apenas incrementan el riesgo de TDAH y difícilmente justifican su elevada heredabilidad. Muchas de ellas están presentes en más del 60% de la población general, lo que sugiere su papel modulador más que causal. No obstante, gracias a la irrupción de nuevas técnicas genéticas en los últimos 15 años, se están identificando un mayor número de casos con trastornos genéticos (muchos de ellos monogénicos), cuyas variantes genéticas explican por sí mismas la presencia del TDAH. El estudio detallado de los antecedentes personales y familiares, así como una exploración física completa, puede ayudar a identificar algunos de ellos. La identificación de la causa en este conjunto de casos tiene un valor crucial en el asesoramiento clínico, el consejo genético-familiar y la anticipación pronóstica, así como en la realización o evitación de estudios complementarios y en el diseño del plan terapéutico.

Tatton-Brown-Rahman syndrome: Novel pathogenic variants and new neuroimaging findings.

Tatton-Brown-Rahman syndrome (TBRS) or DNMT3A-overgrowth syndrome is characterized by overgrowth and intellectual disability associated with minor dysmorphic features, obesity, and behavioral problems. It is caused by variants of the DNMT3A gene. We report four patients with this syndrome due to de novo DNMT3A pathogenic variants, contributing to a deeper understanding of the genetic basis and pathophysiology of this autosomal dominant syndrome. Clinical and magnetic resonance imaging assessments were also performed. All patients showed corpus callosum anomalies, small posterior fossa, and a deep left Sylvian fissure; as well as asymmetry of the uncinate and arcuate fascicles and marked increased cortical thickness. These results suggest that structural neuroimaging anomalies have been previously overlooked, where corpus callosum and brain tract alterations might be unrecognized neuroimaging traits of TBRS syndrome caused by DNMT3A variants.

Developmental epileptic encephalopathy in DLG4-related synaptopathy.

OBJECTIVE: The postsynaptic density protein of excitatory neurons PSD-95 is encoded by discs large MAGUK scaffold protein 4 (DLG4), de novo pathogenic variants of which lead to DLG4-related synaptopathy. The major clinical features are developmental delay, intellectual disability (ID), hypotonia, sleep disturbances, movement disorders, and epilepsy. Even though epilepsy is present in 50% of the individuals, it has not been investigated in detail. We describe here the phenotypic spectrum of epilepsy and associated comorbidities in patients with DLG4-related synaptopathy. METHODS: We included 35 individuals with a DLG4 variant and epilepsy as part of a multicenter study. The DLG4 variants were detected by the referring laboratories. The degree of ID, hypotonia, developmental delay, and motor disturbances were evaluated by the referring clinician. Data on awake and sleep electroencephalography (EEG) and/or video-polygraphy and brain magnetic resonance imaging were collected. Antiseizure medication response was retrospectively assessed by the referring clinician. RESULTS: A large variety of seizure types was reported, although focal seizures were the most common. Encephalopathy related to status epilepticus during slow-wave sleep (ESES)/developmental epileptic encephalopathy with spike-wave activation during sleep (DEE-SWAS) was diagnosed in >25% of the individuals. All but one individual presented with neurodevelopmental delay. Regression in verbal and/or motor domains was observed in all individuals who suffered from ESES/DEE-SWAS, as well as some who did not. We could not identify a clear genotype-phenotype relationship even between individuals with the same DLG4 variants. SIGNIFICANCE: Our study shows that a subgroup of individuals with DLG4-related synaptopathy have DEE, and approximately one fourth of them have ESES/DEE-SWAS. Our study confirms DEE as part of the DLG4-related phenotypic spectrum. Occurrence of ESES/DEE-SWAS in DLG4-related synaptopathy requires proper investigation with sleep EEG.

Broadening the clinical spectrum: molecular mechanisms and new phenotypes of ANO3-dystonia.

Anoctamin 3 (ANO3) belongs to a family of transmembrane proteins that form phospholipid scramblases and ion channels. A large number of ANO3 variants were identified as the cause of craniocervical dystonia, but the underlying pathogenic mechanisms remain obscure. It was suggested that ANO3 variants may dysregulate intracellular Ca2+ signalling, as variants in other Ca2+ regulating proteins like hippocalcin were also identified as a cause of dystonia. In this study, we conducted a comprehensive evaluation of the clinical, radiological, and molecular characteristics of four individuals from four families who carried heterozygous variants in ANO3. The median age at follow-up was 6.6 years (ranging from 3.8 to 8.7 years). Three individuals presented with hypotonia and motor developmental delay. Two patients exhibited generalized progressive dystonia, while one patient presented with paroxysmal dystonia. Additionally, another patient exhibited early dyskinetic encephalopathy. One patient underwent bipallidal deep brain stimulation (DBS) and showed a mild but noteworthy response, while another patient is currently being considered for DBS treatment. Neuroimaging analysis of brain MRI studies did not reveal any specific abnormalities. The molecular spectrum included two novel ANO3 variants (V561L and S116L) and two previously reported ANO3 variants (A599D and S651N). As anoctamins are suggested to affect intracellular Ca2+ signals, we compared Ca2+ signalling and activation of ion channels in cells expressing wild type ANO3 and cells expressing ANO variants. Novel V561L and S116L variants were compared with previously reported A599D and S651N variants and with wtANO3 expressed in fibroblasts isolated from patients or when overexpressed in HEK293 cells. We identified ANO3 as a Ca2+-activated phospholipid scramblase that also conducts ions. Impaired Ca2+ signalling and compromised activation of Ca2+ dependent K+ channels were detected in cells expressing ANO3 variants. In the brain striatal cells of affected patients, impaired activation of KCa3.1 channels due to compromised Ca2+ signals may lead to depolarized membrane voltage and neuronal hyperexcitability and may also lead to reduced cellular viability, as shown in the present study. In conclusion, our study reveals the association between ANO3 variants and paroxysmal dystonia, representing the first reported link between these variants and this specific dystonic phenotype. We demonstrate that ANO3 functions as a Ca2+-activated phospholipid scramblase and ion channel; cells expressing ANO3 variants exhibit impaired Ca2+ signalling and compromised activation of Ca2+-dependent K+ channels. These findings provide a mechanism for the observed clinical manifestations and highlight the importance of ANO3 for neuronal excitability and cellular viability.

Pathogenic variants in SMARCA1 cause an X-linked neurodevelopmental disorder modulated by NURF complex composition.

Pathogenic variants in ATP-dependent chromatin remodeling proteins are a recurrent cause of neurodevelopmental disorders (NDDs). The NURF complex consists of BPTF and either the SNF2H (SMARCA5) or SNF2L (SMARCA1) ISWI-chromatin remodeling enzyme. Pathogenic variants in BPTF and SMARCA5 were previously implicated in NDDs. Here, we describe 40 individuals from 30 families with de novo or maternally inherited pathogenic variants in SMARCA1. This novel NDD was associated with mild to severe ID/DD, delayed or regressive speech development, and some recurrent facial dysmorphisms. Individuals carrying SMARCA1 loss-of-function variants exhibited a mild genome-wide DNA methylation profile and a high penetrance of macrocephaly. Genetic dissection of the NURF complex using Smarca1, Smarca5, and Bptfsingle and double mouse knockouts revealed the importance of NURF composition and dosage for proper forebrain development. Finally, we propose that genetic alterations affecting different NURF components result in a NDD with a broad clinical spectrum.

El impacto del TDAH sobre la lectura / The impact of ADHD on reading

Resumen Más allá de la frecuente coexistencia del trastorno por déficit de atención con hiperactividad (TDAH) y el trastorno específico del aprendizaje de la lectura, la presente revisión pretende examinar la evidencia empírica disponible sobre cómo el TDAH impacta negativamente sobre el aprendizaje de la lectura. Los datos existentes apuntan a que la presencia del trastorno (especialmente los síntomas de falta de atención), puede afectar a i) la correcta adquisición de lectura, ya sea de manera directa o a través de su influencia sobre los precursores de la lectura; ii) las propias habilidades de decodificación (precisión y fluidez lectora), tanto de manera directa como indirecta a través de su influencia sobre procesos cognitivos como la distracción o las funciones ejecutivas; y ii) la comprensión lectora, probablemente de manera indirecta por las dificultades eje cutivas y en la memoria de trabajo verbal características del TDAH. Estas conclusiones presentan importantes implicaciones para caracterizar e intervenir mejor sobre las dificultades lectoras en el TDAH, ya sean clínicas o subclínicas.

Abstract Beyond the frequent coexistence of attention deficit hyperactivity disorder (ADHD) and reading dis order (dyslexia), the present review aims to examine the available empirical evidence on how ADHD negatively impacts on learning to read. Existing data suggest that the presence of the disorder (especially inattention symp toms), may affect i) the correct acquisition of reading, either directly or through its influence on the precursors to reading; ii) decoding skills themselves (reading accuracy and fluency), both directly and indirectly through its influence on cognitive processes such as distractibility or executive functions; and iii) reading comprehension, probably indirectly through the executive and verbal memory difficulties characteristic of ADHD. These findings have important implications for better characterizing and intervening on reading difficulties in ADHD, whether clinical or subclinical.

Síndrome cerebeloso cognitivo afectivo tras cerebelitis aguda / Cerebellar cognitive affective syndrome after acute cerebellitis

En el síndrome cerebeloso, cuya causa principal es la cerebelitis aguda, destacan principalmente las alteraciones motoras, si bien no son las únicas consecuencias de esta patología. Los pacientes que se presentan a continuación manifiestan, además de los signos motores, alteraciones cognitivo-afectivas, como déficit de atención, cambios de personalidad, etc. Esto se denomina síndrome cerebeloso cognitivo afectivo, cuyo diagnóstico es poco habitual a pesar de ser una complicación común. Estos casos llaman a reflexionar sobre la importancia de diagnosticar dicho síndrome para poder administrar un tratamiento adecuado y así mejorar la calidad de vida de los pacientes que lo padezcan (AU)

The most common cause of the cerebellar syndrome is acute cerebellitis. The motor disorders stand out in this syndrome. However, there are other symptoms apart from these. The patients presented below show, besides motor disorders, cognitive affective signs such as attention deficit, personality changes, etc. All these latter manifestations form the cerebellar cognitive affective syndrome. Despite having an uncommon diagnosis, it is a frequent complication. These cases prove the importance of diagnosing this syndrome to enhance the patient’s life quality by providing adequate treatment. (AU)

[The impact of ADHD on reading]. / El impacto del TDAH sobre la lectura.

Beyond the frequent coexistence of attention deficit hyperactivity disorder (ADHD) and reading disorder (dyslexia), the present review aims to examine the available empirical evidence on how ADHD negatively impacts on learning to read. Existing data suggest that the presence of the disorder (especially inattention symptoms), may affect i) the correct acquisition of reading, either directly or through its influence on the precursors to reading; ii) decoding skills themselves (reading accuracy and fluency), both directly and indirectly through its influence on cognitive processes such as distractibility or executive functions; and iii) reading comprehension, probably indirectly through the executive and verbal memory difficulties characteristic of ADHD. These findings have important implications for better characterizing and intervening on reading difficulties in ADHD, whether clinical or subclinical.

Más allá de la frecuente coexistencia del trastorno por déficit de atención con hiperactividad (TDAH) y el trastorno específico del aprendizaje de la lectura, la presente revisión pretende examinar la evidencia empírica disponible sobre cómo el TDAH impacta negativamente sobre el aprendizaje de la lectura. Los datos existentes apuntan a que la presencia del trastorno (especialmente los síntomas de falta de atención), puede afectar a i) la correcta adquisición de lectura, ya sea de manera directa o a través de su influencia sobre los precursores de la lectura; ii) las propias habilidades de decodificación (precisión y fluidez lectora), tanto de manera directa como indirecta a través de su influencia sobre procesos cognitivos como la distracción o las funciones ejecutivas; y ii) la comprensión lectora, probablemente de manera indirecta por las dificultades ejecutivas y en la memoria de trabajo verbal características del TDAH. Estas conclusiones presentan importantes implicaciones para caracterizar e intervenir mejor sobre las dificultades lectoras en el TDAH, ya sean clínicas o subclínicas.

Clinical description, molecular delineation and genotype-phenotype correlation in 340 patients with KBG syndrome: addition of 67 new patients.

BACKGROUND: KBG syndrome is a highly variable neurodevelopmental disorder and clinical diagnostic criteria have changed as new patients have been reported. Both loss-of-function sequence variants and large deletions (copy number variations, CNVs) involving ANKRD11 cause KBG syndrome, but no genotype-phenotype correlation has been reported. METHODS: 67 patients with KBG syndrome were assessed using a custom phenotypical questionnaire. Manifestations present in >50% of the patients and a 'phenotypical score' were used to perform a genotype-phenotype correlation in 340 patients from our cohort and the literature. RESULTS: Neurodevelopmental delay, macrodontia, triangular face, characteristic ears, nose and eyebrows were the most prevalentf (eatures. 82.8% of the patients had at least one of seven main comorbidities: hearing loss and/or otitis media, visual problems, cryptorchidism, cardiopathy, feeding difficulties and/or seizures. Associations found included a higher phenotypical score in patients with sequence variants compared with CNVs and a higher frequency of triangular face (71.1% vs 42.5% in CNVs). Short stature was more frequent in patients with exon 9 variants (62.5% inside vs 27.8% outside exon 9), and the prevalence of intellectual disability/attention deficit hyperactivity disorder/autism spectrum disorder was lower in patients with the c.1903_1907del variant (70.4% vs 89.4% other variants). Presence of macrodontia and comorbidities were associated with larger deletion sizes and hand anomalies with smaller deletions. CONCLUSION: We present a detailed phenotypical description of KBG syndrome in the largest series reported to date of 67 patients, provide evidence of a genotype-phenotype correlation between some KBG features and specific ANKRD11 variants in 340 patients, and propose updated clinical diagnostic criteria based on our findings.

Effect of an autism-associated KCNMB2 variant, G124R, on BK channel properties.

BK K+ channels are critical regulators of neuron and muscle excitability, comprised of a tetramer of pore-forming αsubunits from the KCNMA1 gene and cell- and tissue-selective ß subunits (KCNMB1-4). Mutations in KCNMA1 are associated with neurological disorders, including autism. However, little is known about the role of neuronal BK channel ß subunits in human neuropathology. The ß2 subunit is expressed in central neurons and imparts inactivation to BK channels, as well as altering activation and deactivation gating. In this study, we report the functional effect of G124R, a novel KCNMB2 mutation obtained from whole-exome sequencing of a patient diagnosed with autism spectrum disorder. Residue G124, located in the extracellular loop between TM1 and TM2, is conserved across species, and the G124R missense mutation is predicted deleterious with computational tools. To investigate the pathogenicity potential, BK channels were co-expressed with ß2WT and ß2G124R subunits in HEK293T cells. BK/ß2 currents were assessed from inside-out patches under physiological K+ conditions (140/6 mM K+ and 10 µM Ca2+) during activation and inactivation (voltage-dependence and kinetics). Using ß2 subunits lacking inactivation (ß2IR) revealed that currents from BK/ß2IRG124R channels activated 2-fold faster and deactivated 2-fold slower compared with currents from BK/ß2IRWT channels, with no change in the voltage-dependence of activation (V1/2). Despite the changes in the BK channel opening and closing, BK/ß2G124R inactivation rates (τinact and τrecovery), and the V1/2 of inactivation, were unaltered compared with BK/ß2WT channels under standard steady-state voltage protocols. Action potential-evoked current was also unchanged. Thus, the mutant phenotype suggests the ß2G124R TM1-TM2 extracellular loop could regulate BK channel activation and deactivation kinetics. However, additional evidence is needed to validate pathogenicity for this patient-associated variant in KCNMB2.

An HNRNPK-specific DNA methylation signature makes sense of missense variants and expands the phenotypic spectrum of Au-Kline syndrome.

Au-Kline syndrome (AKS) is a neurodevelopmental disorder associated with multiple malformations and a characteristic facial gestalt. The first individuals ascertained carried de novo loss-of-function (LoF) variants in HNRNPK. Here, we report 32 individuals with AKS (26 previously unpublished), including 13 with de novo missense variants. We propose new clinical diagnostic criteria for AKS that differentiate it from the clinically overlapping Kabuki syndrome and describe a significant phenotypic expansion to include individuals with missense variants who present with subtle facial features and few or no malformations. Many gene-specific DNA methylation (DNAm) signatures have been identified for neurodevelopmental syndromes. Because HNRNPK has roles in chromatin and epigenetic regulation, we hypothesized that pathogenic variants in HNRNPK may be associated with a specific DNAm signature. Here, we report a unique DNAm signature for AKS due to LoF HNRNPK variants, distinct from controls and Kabuki syndrome. This DNAm signature is also identified in some individuals with de novo HNRNPK missense variants, confirming their pathogenicity and the phenotypic expansion of AKS to include more subtle phenotypes. Furthermore, we report that some individuals with missense variants have an "intermediate" DNAm signature that parallels their milder clinical presentation, suggesting the presence of an epi-genotype phenotype correlation. In summary, the AKS DNAm signature may help elucidate the underlying pathophysiology of AKS. This DNAm signature also effectively supported clinical syndrome delineation and is a valuable aid for variant interpretation in individuals where a clinical diagnosis of AKS is unclear, particularly for mild presentations.

GIGYF1 disruption associates with autism and impaired IGF-1R signaling.

Autism spectrum disorder (ASD) represents a group of neurodevelopmental phenotypes with a strong genetic component. An excess of likely gene-disruptive (LGD) mutations in GIGYF1 was implicated in ASD. Here, we report that GIGYF1 is the second-most mutated gene among known ASD high-confidence risk genes. We investigated the inheritance of 46 GIGYF1 LGD variants, including the highly recurrent mutation c.333del:p.L111Rfs*234. Inherited GIGYF1 heterozygous LGD variants were 1.8 times more common than de novo mutations. Among individuals with ASD, cognitive impairments were less likely in those with GIGYF1 LGD variants relative to those with other high-confidence gene mutations. Using a Gigyf1 conditional KO mouse model, we showed that haploinsufficiency in the developing brain led to social impairments without significant cognitive impairments. In contrast, homozygous mice showed more severe social disability as well as cognitive impairments. Gigyf1 deficiency in mice led to a reduction in the number of upper-layer cortical neurons, accompanied by a decrease in proliferation and increase in differentiation of neural progenitor cells. We showed that GIGYF1 regulated the recycling of IGF-1R to the cell surface. KO of GIGYF1 led to a decreased level of IGF-1R on the cell surface, disrupting the IGF-1R/ERK signaling pathway. In summary, our findings show that GIGYF1 is a regulator of IGF-1R recycling. Haploinsufficiency of GIGYF1 was associated with autistic behavior, likely through interference with IGF-1R/ERK signaling pathway.

HDAC9 structural variants disrupting TWIST1 transcriptional regulation lead to craniofacial and limb malformations.

Structural variants (SVs) can affect protein-coding sequences as well as gene regulatory elements. However, SVs disrupting protein-coding sequences that also function as cis-regulatory elements remain largely uncharacterized. Here, we show that craniosynostosis patients with SVs containing the histone deacetylase 9 (HDAC9) protein-coding sequence are associated with disruption of TWIST1 regulatory elements that reside within the HDAC9 sequence. Based on SVs within the HDAC9-TWIST1 locus, we defined the 3'-HDAC9 sequence as a critical TWIST1 regulatory region, encompassing craniofacial TWIST1 enhancers and CTCF sites. Deletions of either Twist1 enhancers (eTw5-7Δ/Δ) or CTCF site (CTCF-5Δ/Δ) within the Hdac9 protein-coding sequence led to decreased Twist1 expression and altered anterior/posterior limb expression patterns of SHH pathway genes. This decreased Twist1 expression results in a smaller sized and asymmetric skull and polydactyly that resembles Twist1+/- mouse phenotype. Chromatin conformation analysis revealed that the Twist1 promoter interacts with Hdac9 sequences that encompass Twist1 enhancers and a CTCF site, and that interactions depended on the presence of both regulatory regions. Finally, a large inversion of the entire Hdac9 sequence (Hdac9 INV/+) in mice that does not disrupt Hdac9 expression but repositions Twist1 regulatory elements showed decreased Twist1 expression and led to a craniosynostosis-like phenotype and polydactyly. Thus, our study elucidates essential components of TWIST1 transcriptional machinery that reside within the HDAC9 sequence. It suggests that SVs encompassing protein-coding sequences could lead to a phenotype that is not attributed to its protein function but rather to a disruption of the transcriptional regulation of a nearby gene.

A Novel Loss-of-Function SEMA3E Mutation in a Patient with Severe Intellectual Disability and Cognitive Regression.

Intellectual disability (ID) is a neurological disorder arising from early neurodevelopmental defects. The underlying genetic and molecular mechanisms are complex, but are thought to involve, among others, alterations in genes implicated in axon guidance and/or neural circuit formation as demonstrated by studies on mouse models. Here, by combining exome sequencing with in silico analyses, we identified a patient affected by severe ID and cognitive regression, carrying a novel loss-of-function variant in the semaphorin 3E (SEMA3E) gene, which encodes for a key secreted cue that controls mouse brain development. By performing ad hoc in vitro and ex vivo experiments, we found that the identified variant impairs protein secretion and hampers the binding to both embryonic mouse neuronal cells and tissues. Further, we revealed SEMA3E expression during human brain development. Overall, our findings demonstrate the pathogenic impact of the identified SEMA3E variant and provide evidence that clinical neurological features of the patient might be due to a defective SEMA3E signaling in the brain.

Functional and structural deficiencies of Gemin5 variants associated with neurological disorders.

Dysfunction of RNA-binding proteins is often linked to a wide range of human disease, particularly with neurological conditions. Gemin5 is a member of the survival of the motor neurons (SMN) complex, a ribosome-binding protein and a translation reprogramming factor. Recently, pathogenic mutations in Gemin5 have been reported, but the functional consequences of these variants remain elusive. Here, we report functional and structural deficiencies associated with compound heterozygosity variants within the Gemin5 gene found in patients with neurodevelopmental disorders. These clinical variants are located in key domains of Gemin5, the tetratricopeptide repeat (TPR)-like dimerization module and the noncanonical RNA-binding site 1 (RBS1). We show that the TPR-like variants disrupt protein dimerization, whereas the RBS1 variant confers protein instability. All mutants are defective in the interaction with protein networks involved in translation and RNA-driven pathways. Importantly, the TPR-like variants fail to associate with native ribosomes, hampering its involvement in translation control and establishing a functional difference with the wild-type protein. Our study provides insights into the molecular basis of disease associated with malfunction of the Gemin5 protein.

Bi-Allelic c.1746G>T; p.Leu582= Variants in TUBGCP4 in a Boy with Autism: Clinical Data and Literature Review.

Bi-allelic mutations in the TUBGCP4 gene have been recently associated with autosomal recessive microcephaly with chorioretinopathy. However, little is known about the genotype-phenotype characteristics of this disorder. Here, we describe a 5-year-old male patient with autism and a normal occipitofrontal circumference. No retinal abnormalities were observed. Brain MRI revealed the presence of enlarged sheaths of both tortuous optic nerves; both eyes had shorter axial lengths. Whole-exome sequencing in trio revealed synonymous TUBGCP4 variants in homozygous state: c.1746G>T; p.Leu582=. This synonymous variant has been previously described and probably leads to skipping of exon 16 of TUBGCP4. These results broaden the clinical spectrum of this new syndrome and suggest that TUBGCP4 bi-allelic mutations may underlie complex neurodevelopmental disorders.

Mutations in the COL18A1 gen associated with knobloch syndrome and structural brain anomalies: a novel case report and literature review of neuroimaging findings.

. COL18A1 gene mutations have been associated with Knobloch syndrome, which is characterized by ocular and brain abnormalities. Here we report a 4.5 years-old male child with autism and two novel COL18A1 mutations (NM_030582.4: c.1883_1891dup and c.1787C>T). Hypermetropic astigmatism, but not brain migration disorders, was observed. However, an asymmetric pattern of cerebellar perfusion and a smaller arcuate fascicle were found.  Low levels of collagen XVIII were also observed in the patient´s serum. Thus, biallelic loss-of-function mutations in COL18A1 may be a new cause of autism  without the brain malformations typically reported in patients with Knobloch syndrome.

Déficits neuropsicológicos, intensidad sintomática y repercusión funcional en el trastorno por déficit de atención con hiperactividad / Neuropsychological deficits, symptom intensity and functional impairment in attention deficit hyperactivity disorder

Resumen Este estudio pretende contribuir a una mejor comprensión del trastorno por déficit de atención con hiperactividad (TDAH) examinado de manera exhaustiva la relación entre dos de los principales déficits cognitivos del trastorno (la atención y el control inhibitorio), la sintomatología (falta de atención e hipe ractividad/impulsividad) y la repercusión funcional en 85 niños/as y adolescentes con TDAH sin otros trastornos comórbidos. Encontramos, con independencia del funcionamiento intelectual general y de la edad, que i) un mayor déficit atencional e inhibitorio, predijo una mayor gravedad de los síntomas del TDAH, ii) un mayor déficit atencional e inhibitorio predijo un mayor deterioro funcional, pero no de una manera directa sino a través de los síntomas, y iii) una mayor severidad sintomática predijo una mayor repercusión funcional. Comenzar a explorar y comprender la complejidad del TDAH es clave para avanzar en nuestro conocimiento del trastorno y para la correcta toma de decisiones clínicas.

Abstract This study aims to contribute to a better understanding of at tention deficit hyperactivity disorder (ADHD) by comprehensively examining the relationship between two of the main cognitive deficits of the disorder (attention and inhibitory control), symptomatology (inattention and hyperactivity/impulsivity) and functional impairment in 85 children and adolescents with ADHD without other comorbid disorders. We found, independent of general intellectual functioning and age, that i) greater atten tional and inhibitory deficits predicted greater severity of ADHD symptoms, ii) greater attentional and inhibitory deficits predicted greater functional impairment, but not in a direct way but through symptoms, and iii) greater symptomatic severity predicted greater functional impairment. Beginning to explore and understand the com plexity of ADHD is key to advance our knowledge of the disorder and for correct clinical decision making.

[Neuropsychological deficit, symptom intensity and functional impairment in attention deficit hyperactivity disorder]. / Déficits neuropsicológicos, intensidad sintomática y repercusión funcional en el trastorno por déficit de atención con hiperactividad.

This study aims to contribute to a better understanding of attention deficit hyperactivity disorder (ADHD) by comprehensively examining the relationship between two of the main cognitive deficits of the disorder (attention and inhibitory control), symptomatology (inattention and hyperactivity/impulsivity) and functional impairment in 85 children and adolescents with ADHD without other comorbid disorders. We found, independent of general intellectual functioning and age, that i) greater attentional and inhibitory deficits predicted greater severity of ADHD symptoms, ii) greater attentional and inhibitory deficits predicted greater functional impairment, but not in a direct way but through symptoms, and iii) greater symptomatic severity predicted greater functional impairment. Beginning to explore and understand the complexity of ADHD is key to advance our knowledge of the disorder and for correct clinical decision making.

Este estudio pretende contribuir a una mejor comprensión del trastorno por déficit de atención con hiperactividad (TDAH) examinado de manera exhaustiva la relación entre dos de los principales déficits cognitivos del trastorno (la atención y el control inhibitorio), la sintomatología (falta de atención e hiperactividad / impulsividad) y la repercusión funcional en 85 niños/as y adolescentes con TDAH sin otros trastornos comórbidos. Encontramos, con independencia del funcionamiento intelectual general y de la edad, que i) un mayor déficit atencional e inhibitorio, predijo una mayor gravedad de los síntomas del TDAH, ii) un mayor déficit atencional e inhibitorio predijo un mayor deterioro funcional, pero no de una manera directa sino a través de los síntomas, y iii) una mayor severidad sintomática predijo una mayor repercusión funcional. Comenzar a explorar y comprender la complejidad del TDAH es clave para avanzar en nuestro conocimiento del trastorno y para la correcta toma de decisiones clínicas.