A homozygous variant in ARHGAP39 is associated with lethal cerebellar vermis hypoplasia in a consanguineous Saudi family.

Cerebellar vermis hypoplasia refers to a varying degree of incomplete development of the cerebellum and vermis. A Saudi family with four affected individuals with cerebellar vermis hypoplasia, facial dysmorphology, visual impairment, skeletal, and cardiac abnormalities was ascertained in this study. Three out of four patients could not survive longer and had died in early infancy. Genetic analysis of the youngest affected was performed by genome-wide homozygosity mapping coupled with whole exome sequencing (WES), followed by Sanger validation. Genome-wide genotyping analysis mapped the phenotype to chromosome 8q24.3. Using an autosomal recessive model, considering deleterious variants with minor allele frequency of less than 0.001 in WES data, a homozygous missense variant (NM_025251.2; ARHGAP39; c.1301G > T; p.Cys434Phe) was selected as a potential candidate for the phenotype. The variant (c.1301G > T) in the ARHGAP39 is in the region of homozygosity on chromosome 8q24.3. ARHGAP39 is a Rho GTPase-activating protein 39 and has been known to regulate apoptosis, cell migration, neurogenesis, and cerebral and hippocampal dendritic spine morphology. Mice homozygous for arhgap39 knockouts have shown premature embryonic lethality. Our findings present the first ever human phenotype associated with ARHGAP39 alteration.

Application of Whole-Exome Sequencing in the Prenatal Diagnosis of Foetuses With Central Nervous System Abnormalities.

OBJECTIVE: To investigate the clinical value of whole-exome sequencing (WES) in the diagnosis of foetuses with central nervous system (CNS) abnormalities but having a normal karyotyping and chromosomal microarray result. METHOD: During the period of 2016-2022, there were a total of 149 foetuses with CNS abnormalities but having negative karyotyping and chromosomal microarray analysis results; WES was performed on these foetuses and their parents. Variants were classified according to ACMG guidelines, and the association of pathogenic variants with specific types of CNS abnormalities was explored. RESULTS: Among these 149 foetuses, three categories of abnormalities, namely, single CNS abnormality, multiple CNS abnormalities, CNS abnormalities along with other organ system abnormalities were identified, for which the detection rate of P/LP variants is 17.4% (12/69), 28.6% (14/49) and 54.8% (17/31), respectively. CONCLUSION: WES brought about an increase of 28.9% in diagnostic yield in the prenatal evaluation of foetuses with CNS abnormalities but having negative karyotyping and chromosome array results. WES may also be of benefit for the diagnosis of foetuses with isolated CNS abnormalities, as well as for making more informed interpretations of imaging findings and for providing better genetic counselling.

Second generation lethality in RNAseH2a knockout zebrafish.

Removal of ribonucleotides from DNA by RNaseH2 is essential for genome stability, and its impacted function causes the neurodegenerative disease, Aicardi Goutières Syndrome. We have created a zebrafish rnaseh2a mutant to model this process. Surprisingly, RNaseH2a knockouts show little phenotypic abnormality at adulthood in the first generation, unlike mouse knockout models, which are early embryonic lethal. However, the second generation offspring show reduced development, increased ribonucleotide incorporation and upregulation of key inflammatory markers, resulting in both maternal and paternal embryonic lethality. Thus, neither fathers or mothers can generate viable offspring even when crossed to wild-type partners. Despite their survival, rnaseh2a-/- adults show an accumulation of ribonucleotides in both the brain and testes that is not present in early development. Our data suggest that homozygotes possess RNaseH2 independent compensatory mechanisms that are inactive or overwhelmed by the inherited ribonucleotides in their offspring, or that zebrafish have a yet unknown tolerance mechanism. Additionally, we identify ribodysgenesis, the rapid removal of rNMPs and subsequently lethal fragmentation of DNA as responsible for maternal and paternal embryonic lethality.

Systemic complications of Aicardi Goutières syndrome using real-world data.

OBJECTIVE: Aicardi Goutières Syndrome (AGS) is a rare genetic interferonopathy associated with diverse multisystemic complications. A critical gap exists in our understanding of its longitudinal, systemic disease burden, complicated by delayed diagnosis. To address this need, real-world data extracted from existing medical records were used to characterize the longitudinal disease burden. METHODS: All subjects (n = 167) with genetically confirmed AGS enrolled in the Myelin Disorders Biorepository Project (MDBP) were included. As available in medical records, information was collected on subject demographics, age of onset, and disease complications. Information from published cases of AGS (2007-2022; n = 129) with individual-level data was also collected. Neurologic severity at the last available encounter was determined by retrospectively assigning the AGS Severity Scale [severe (0-3), moderate (4-8), and mild (9-11)]. RESULTS: The genotype frequency in the natural history cohort was TREX1 (n = 26, 15.6 %), RNASEH2B (n = 50, 29.9 %), RNASEH2C (n = 3, 1.8 %), RNASEH2A (n = 7, 4.2 %), SAMHD1 (n = 25, 15.0 %), ADAR (n = 34, 20.4 %), IFIH1 (n = 19, 11.4 %), and RNU7-1 (n = 3, 1.8 %). The median age of systemic onset was 0.15 years [IQR = 0.67 years; median range by genotype: 0 (TREX1) - 0.62 (ADAR) years], while the median neurological onset was 0.33 years [IQR = 0.82 years; median range by genotype: 0.08 (TREX1) - 0.90 (ADAR) year]. The most common early systemic complications were gastrointestinal, including dysphagia or feeding intolerance (n = 124) and liver abnormalities (n = 67). Among postnatal complications, thrombocytopenia appeared earliest (n = 29, median 0.06 years). Tone abnormalities (axial hypotonia: n = 145, 86.8 %; dystonia: n = 123, 73.7 %), irritability (n = 115, 68.9 %), and gross motor delay (n = 112, 7.1 %) emerged as the most prevalent neurological symptoms. Previously published case reports demonstrated similar patterns. The median AGS score for the entire cohort was 4 (IQR = 7). The most severe neurologic phenotype occurred in TREX1-related AGS (n = 19, median AGS severity score 2, IQR = 2). Time to feeding tube placement, chilblains, early gross motor delay, early cognitive delay, and motor regression were significantly associated with genotype (Fleming-Harrington log-rank: p = 0.0002, p < 0.0001, p = 0.0038, p < 0.0001, p = 0.0001, respectively). Microcephaly, feeding tube placement, and seizures were associated with lower AGS scores (All: Wilcoxon rank sum test, p < 0.0001). Among the qualifying case reports (n = 129), tone abnormalities were the most prevalent disease feature, with spastic quadriplegia reported in 37 of 96 cases (38.5 %) and dystonia in 30 of 96 cases (31.2 %). CONCLUSIONS: AGS is a heterogeneous disease with multi-organ system dysfunction that compounds throughout the clinical course, resulting in profound neurological and extra-neurological disease impact. Systemic symptoms precede neurologic disease features in most cases. Disease onset before the age of one year, microcephaly, feeding tube placement, and seizures were associated with worse neurological outcomes. This work will inform evidence-based clinical monitoring guidelines and clinical trial design.

cGAS activation in classical dendritic cells causes autoimmunity in TREX1-deficient mice.

Detection of cytosolic DNA by the cyclic GMP-AMP (cGAMP) synthase (cGAS)-stimulator of interferon genes (STING) pathway provides immune defense against pathogens and cancer but can also cause autoimmunity when overactivated. The exonuclease three prime repair exonuclease 1 (TREX1) degrades DNA in the cytosol and prevents cGAS activation by self-DNA. Loss-of-function mutations of the TREX1 gene are linked to autoimmune diseases such as Aicardi-Goutières syndrome, and mice deficient in TREX1 develop lethal inflammation in a cGAS-dependent manner. In order to determine the type of cells in which cGAS activation drives autoinflammation, we generated conditional cGAS knockout mice on the Trex1-/- background. Here, we show that genetic ablation of the cGAS gene in classical dendritic cells (cDCs), but not in macrophages, was sufficient to rescue Trex1-/- mice from all observed disease phenotypes including lethality, T cell activation, tissue inflammation, and production of antinuclear antibodies and interferon-stimulated genes. These results show that cGAS activation in cDC causes autoinflammation in response to self-DNA accumulated in the absence of TREX1.

Detection of genomic variants by genome sequencing in foetuses with central nervous system abnormalities.

OBJECTIVE: Clinical validity of genome sequencing (GS) (>30×) has been preliminarily verified in the post-natal setting. This study is to investigate the potential utility of trio-GS as a prenatal test for diagnosis of central nervous system (CNS) anomalies. METHODS: We performed trio-based GS on a prospective cohort of 17 foetuses with CNS abnormalities. Single nucleotide variation (SNV), small insertion and deletion (Indel), copy number variation (CNV), structural variant (SV), and regions with absence of heterozygosity (AOH) were analyzed and classified according to ACMG guidelines. RESULTS: Trio-GS identified diagnostic findings in 29.4% (5/17) of foetuses, with pathogenic variants found in SON, L1CAM, KMT2D, and ASPM. Corpus callosum (CC) and cavum septum pellucidum (CSP) abnormalities were the most frequent CNS abnormalities (47.1%, 8/17) with a diagnostic yield of 50%. A total of 29.4% (5/17) foetuses had variants of uncertain significance (VUS). Particularly, maternal uniparental disomy 16 and a de novo mosaic 4p12p11 duplication were simultaneously detected in one foetus with abnormal sulcus development. In addition, parentally inherited chromosomal inversions were identified in two foetuses. CONCLUSION: GS demonstrates its feasibility in providing genetic diagnosis for foetal CNS abnormalities and shows the potential to expand the application to foetuses with other ultrasound anomalies in prenatal diagnosis.

Perinatal lethal form Gaucher disease with compound heterozygosity of single nucleotide variants and copy number variations presenting as nonimmune hydrops fetalis and cerebellar hypoplasia: A case report.

OBJECTIVE: To present the ultrasound imaging and genetic diagnosis of a fetus with prenatal lethal form of Gaucher disease. CASE REPORT: A 37-year-old primiparous woman was pregnant at her 23 weeks of gestation and the prenatal fetal ultrasound revealed hydrops fetalis, cerebellum hypoplasia, and fetal immobility. The pregnancy was terminated due to major fetal anomaly, and whole exome sequencing (WES) analysis of fetal tissue and parental blood unveiled a pathogenic variant in exon 10 of the GBA gene (NM_001005741.3: c.1265T > G: p.L422R) originating from the mother. Additionally, a novel CNV (chr1: 155204785-155205635 deletion, 0.85 kb) spanning exon 10-12 in the GBA gene was identified from the father. This compound heterozygosity confirmed the diagnosis of prenatal lethal form of Gaucher disease and was informative for genetic counseling. CONCLUSION: WES is a powerful tool to detect pathogenic variants among fetuses with nonimmune hydrops fetalis and complex abnormality from prenatal ultrasound. Compound heterozygosity consisted of single nucleotide variants (SNV) and copy number variations (CNVs) may lead rare inherited metabolic disorders including prenatal lethal form of Gaucher disease.

Childhood-inherited white matter disorders with calcification.

Intracranial calcification (ICC) occurs in many neurologic disorders both acquired and genetic. In some inherited white matter disorders, it is a common or even invariable feature where the presence and pattern of calcification provides an important pointer to the specific diagnosis. This is particularly the case for the Aicardi-Goutières syndrome (AGS) and for Coats plus (CP) and leukoencephalopathy with calcifications and cysts (LCC), which are discussed in detail in this chapter. AGS is a genetic disorder of type 1 interferon regulation, caused by mutations in any of the nine genes identified to date. In its classic form, AGS has very characteristic clinical and neuroimaging features which will be discussed here. LCC is a purely neurologic disorder caused by mutations in the SNORD118 gene, whereas CP is a multisystem disorder of telomere function that may result from mutations in the CTC1, POT1, or STN genes. In spite of the different pathogenetic basis for LCC and CP, they share remarkably similar neuroimaging and neuropathologic features. Cockayne syndrome, in which ICC is usually present, is discussed elsewhere in this volume. ICC may occur as an occasional feature of many other white matter diseases, including Alexander disease, Krabbe disease, X-ALD, and occulodentodigital dysplasia.

Interferonopathies: From concept to clinical practice.

The horror autoinflammaticus derived from aberrant type I interferon secretion determines a special group of autoinflammatory diseases named interferonopathies. Diverse mechanisms involved in nucleic acids sensing, metabolizing or the lack of interferon signaling retro-control are responsible for the phenotypes associated to Aicardi-Goutières Syndrome (AGS), Proteasome-Associated Autoinflammatory Diseases (PRAAS), STING-Associated Vasculopathy with Infancy Onset (SAVI) and certain forms of monogenic Systemic lupus erythematosus (SLE). This review approaches interferonopathies from the basic immunogenetic concept to diagnosis and treatment.

The brain microvasculature is a primary mediator of interferon-α neurotoxicity in human cerebral interferonopathies.

Aicardi-Goutières syndrome (AGS) is an autoinflammatory disease characterized by aberrant interferon (IFN)-α production. The major cause of morbidity in AGS is brain disease, yet the primary source and target of neurotoxic IFN-α remain unclear. Here, we demonstrated that the brain was the primary source of neurotoxic IFN-α in AGS and confirmed the neurotoxicity of intracerebral IFN-α using astrocyte-driven Ifna1 misexpression in mice. Using single-cell RNA sequencing, we demonstrated that intracerebral IFN-α-activated receptor (IFNAR) signaling within cerebral endothelial cells caused a distinctive cerebral small vessel disease similar to that observed in individuals with AGS. Magnetic resonance imaging (MRI) and single-molecule ELISA revealed that central and not peripheral IFN-α was the primary determinant of microvascular disease in humans. Ablation of endothelial Ifnar1 in mice rescued microvascular disease, stopped the development of diffuse brain disease, and prolonged lifespan. These results identify the cerebral microvasculature as a primary mediator of IFN-α neurotoxicity in AGS, representing an accessible target for therapeutic intervention.

Presentation of Rare Phenotypes Associated with the FKBP10 Gene.

Pathogenic variants in the FKBP10 gene lead to a spectrum of rare autosomal recessive phenotypes, including osteogenesis imperfecta (OI) Type XI, Bruck syndrome Type I (BS I), and the congenital arthrogryposis-like phenotype (AG), each with variable clinical manifestations that are crucial for diagnosis. This study analyzed the clinical-genetic characteristics of patients with these conditions, focusing on both known and newly identified FKBP10 variants. We examined data from 15 patients, presenting symptoms of OI and joint contractures. Diagnostic methods included genealogical analysis, clinical assessments, radiography, whole exome sequencing, and direct automated Sanger sequencing. We diagnosed 15 patients with phenotypes due to biallelic FKBP10 variants-4 with OI Type XI, 10 with BS I, and 1 with the AG-like phenotype-demonstrating polymorphism in disease severity. Ten pathogenic FKBP10 variants were identified, including three novel ones, c.1373C>T (p.Pro458Leu), c.21del (p.Pro7fs), and c.831_832insCG (p.Gly278Argfs), and a recurrent variant, c.831dup (p.Gly278Argfs). Variant c.1490G>A (p.Trp497Ter) was found in two unrelated patients, causing OI XI in one and BS I in the other. Additionally, two unrelated patients with BS I and epidermolysis bullosa shared identical homozygous FKBP10 and KRT14 variants. This observation illustrates the diversity of FKBP10-related pathology and the importance of considering the full spectrum of phenotypes in clinical diagnostics.

IFN-signaling gene expression as a diagnostic biomarker for monogenic interferonopathies.

IFN-signaling gene (ISG) expression scores are potential markers of inflammation with significance from cancer to genetic syndromes. In Aicardi Goutières Syndrome (AGS), a disorder of abnormal DNA and RNA metabolism, this score has potential as a diagnostic biomarker, although the approach to ISG calculation has not been standardized or validated. To optimize ISG calculation and validate ISG as a diagnostic biomarker, mRNA levels of 36 type I IFN response genes were quantified from 997 samples (including 334 AGS), and samples were randomized into training and test data sets. An independent validation cohort (n = 122) was also collected. ISGs were calculated using all potential combinations up to 6 genes. A 4-gene approach (IFI44L, IFI27, USP18, IFI6) was the best-performing model (AUC of 0.8872 [training data set], 0.9245 [test data set]). The majority of top-performing gene combinations included IFI44L. Performance of IFI44L alone was 0.8762 (training data set) and 0.9580 (test data set) by AUC. The top approaches were able to discriminate individuals with genetic interferonopathy from control samples. This study validates the context of use for the ISG score as a diagnostic biomarker and underscores the importance of IFI44L in diagnosis of genetic interferonopathies.

Neurological Findings and a Brief Review of the Current Literature in a Severe Case of Aicardi-Goutières Syndrome Due to an IFIH1 Mutation.

Aicardi-Goutières syndrome (AGS) is a rare genetic early-onset progressive encephalopathy with variable clinical manifestations. The IFIH1 mutation has been confirmed to be responsible for type I interferon production and activation of the Janus kinase signaling pathway. We herein stress neurological observations and neuroimaging findings in a severe case report of an infant with AGS type 7 due to an IFIH1 mutation who was diagnosed in the first month of life. We also review neurological characteristics of IFIH1 mutations through recent literature.

CASK pathogenic variant which expands the clinical spectrum for MICPCH syndrome in an adult patient.

The CASK gene and its product protein kinase have been associated with microcephaly with pontine and cerebellar hypoplasia (MICPCH) syndrome and various other neurodevelopmental disorders. Clinical presentation is highly variable and generally includes intellectual disability, neurological disorders, and dysmorphic features, at a minimum. We present the case of one of the oldest known currently living patients with MICPCH syndrome with additional features not previously described in the literature (midface retrusion, macroglossia, dental crowding, adolescent-onset contractures at large joints, laxity at finger joints, and prominent wrist dystonia). Progressive hypertonicity throughout the patient's life has been managed with serial botulinum toxin injections. A comprehensive multimodal care team including physiatry, physical therapy, exercise therapy, and audiology has been assisting her with hearing deficits, communication skills, and mobility. This potentially expands the phenotype of MICPCH syndrome and provides information about the management of this condition into adulthood.

Mutations in the non-catalytic polyproline motif destabilize TREX1 and amplify cGAS-STING signaling.

The cGAS-STING pathway detects cytosolic DNA and activates a signaling cascade that results in a type I interferon (IFN) response. The endoplasmic reticulum (ER)-associated exonuclease TREX1 suppresses cGAS-STING by eliminating DNA from the cytosol. Mutations that compromise TREX1 function are linked to autoinflammatory disorders, including systemic lupus erythematosus (SLE) and Aicardi-Goutières syndrome (AGS). Despite key roles in regulating cGAS-STING and suppressing excessive inflammation, the impact of many disease-associated TREX1 mutations-particularly those outside of the core catalytic domains-remains poorly understood. Here, we characterize a recessive AGS-linked TREX1 P61Q mutation occurring within the poorly characterized polyproline helix (PPII) motif. In keeping with its position outside of the catalytic core or ER targeting motifs, neither the P61Q mutation, nor aggregate proline-to-alanine PPII mutation, disrupts TREX1 exonuclease activity, subcellular localization, or cGAS-STING regulation in overexpression systems. Introducing targeted mutations into the endogenous TREX1 locus revealed that PPII mutations destabilize the protein, resulting in impaired exonuclease activity and unrestrained cGAS-STING activation. Overall, these results demonstrate that TREX1 PPII mutations, including P61Q, impair proper immune regulation and lead to autoimmune disease through TREX1 destabilization.

Central nervous system anomalies in 41 Chinese children incontinentia pigmenti.

INTRODUCTION: Incontinentia pigmenti (IP) is a rare neuroectodermal dysplasia caused by a defect in the IKBKG gene. The pathogenesis of central nervous system injury is believed to be related to microvascular ischemia. Currently, few treatment strategies are available for the inflammatory phase. MATERIALS AND METHODS: This retrospective descriptive analysis included the clinical data of 41 children with IP collected from 2007 to 2021 in Xi'an, China, comprising clinical characteristics, imaging findings, blood cell analysis, skin histopathology, and genetic data. RESULTS: Fourteen children (34%) aged 4 days to 5 months exhibited clinical signs and symptoms, including convulsions, delayed psychomotor development following neurological damage, and revealed significant MRI abnormalities, including ischemia, hypoxia, cerebral hypoperfusion, hemorrhage, encephalomalacia, and cerebral atrophy. Eight of the 24 patients (33%) presented with retinal vascular tortuosity and telangiectasis, accompanied by neovascularization and hemorrhage. Thirty-eight children (93%) had elevated eosinophils (mean: 3.63 ± 4.46 × 109), and 28 children (68%) had significantly elevated platelets (mean: 420.16 ± 179.43 × 109). Histopathology of skin revealed microvascular extravasation and vasodilation with perivascular and intravascular eosinophilic infiltration. CONCLUSION: Brain injury in IP occurs during infancy until 5 months of age, which is also the acute dermatitis phase accompanied by eosinophilia and an increased platelet count. This study provides evidence of microvascular damage to the skin and fundus during the inflammatory phase. The mechanism of microvascular damage may be similar to that in the brain.

Indomethacin restrains cytoplasmic nucleic acid-stimulated immune responses by inhibiting the nuclear translocation of IRF3.

The recognition of cytosolic nucleic acid triggers the DNA/RNA sensor-IRF3 axis-mediated production of type I interferons (IFNs), which are essential for antiviral immune responses. However, the inappropriate activation of these signaling pathways is implicated in autoimmune conditions. Here, we report that indomethacin, a widely used nonsteroidal anti-inflammatory drug, inhibits nucleic acid-triggered IFN production. We found that both DNA- and RNA-stimulated IFN expression can be effectively blocked by indomethacin. Interestingly, indomethacin also prohibits the nuclear translocation of IRF3 following cytosolic nucleic acid recognition. Importantly, in cell lines and a mouse model of Aicardi-Goutières syndrome, indomethacin administration blunts self-DNA-induced autoimmune responses. Thus, our study reveals a previously unknown function of indomethacin and provides a potential treatment for cytosolic nucleic acid-stimulated autoimmunity.

[Congenital brain malformations]. / Angeborene Hirnfehlbildungen.

CLINICAL ISSUE: Malformations of the central nervous system belong to the most common developmental disorders in humans. The clinical presentation of brain malformations is nonspecific including developmental delay, hypotonia, and/or epilepsy. The great heterogeneity concerning etiology, mechanisms of development and morphology is challenging for diagnosis and classification of brain malformations. Thereby recognizing specific malformations is essential for optimal patient management and prognostic evaluation. The aim of this article is to give an overview of several clinically relevant brain malformations occurring from different disrupted developmental processes in brain formation. STANDARD RADIOLOGICAL METHODS: Several brain malformations are already diagnosed during routine ultrasound in pregnancy. However pre- and postnatal magnetic resonance imaging remains the gold standard in detecting the partially subtle changes and to classify the malformations. METHODICAL INNOVATIONS: Advances in pre- and postnatal neuroimaging techniques and increasing investigation of genetic mechanisms underlying brain formation and its abnormalities have led to a better understanding of embryologic development and pathogeneses of brain malformations. CONCLUSION: Besides patient's history and clinical phenotype, neuroimaging plays a key role in diagnosis. Not always a specific diagnosis can be made, but neuroimaging patterns often enable a focused genetic testing and therefore are revolutionary for etiologic and prognostic assignment. Basic knowledge of brain development facilitates understanding and classifying of structural brain abnormalities.

[Expression changes of RNA m6A regulators in mouse cerebellum affected by hypobaric hypoxia stimulation].

Objective: To investigate the role of RNA m6A methylation in mediating cerebellar dysplasia through analyzing the phenotypes of the mouse cerebella and the expression of several key m6A regulators upon hypobaric hypoxia treatment. Methods: Five-day old C57/BL6 mice were exposed to hypobaric hypoxia for 9 days. The status of mouse cerebellar development was analyzed by comparing the body weights, brain weights and histological features. Immunostaining of cell-type-specific markers was performed to analyze the cerebellar morphology. Real-time PCR, Western blot and immunohistochemical staining were performed to detect the expression of key m6A regulators in the mouse cerebella. Results: Compared with the control, the body weights, brain weights and cerebellar volumes of hypobaric hypoxic mice were significantly reduced (P<0.01). The expression of specific markers in different cells, including NeuN (mature neuron), Calbindin-D28K (Purkinje cell) and GFAP (astrocyte), was decreased in hypobaric hypoxic mouse cerebella (P<0.01), accompanied with disorganized cellular structure. The expression of methyltransferase METTL3 was significantly down-regulated in the cerebella of hypobaric hypoxic mice (P<0.05). Conclusions: Hypobaric hypoxia stimulation causes mouse cerebellar dysplasia, with structural abnormalities in mature granular neurons, Purkinje cells and astrocytes. Expression of METTL3 is decreased in hypobaric hypoxic mice cerebellum compared with that of normobaric normoxic mice, suggesting that its mediated RNA m6A methylation may play an important role in hypobaric hypoxia-induced mouse cerebellar dysplasia.

Characterization of Fine Motor and Visual Motor Skills in Aicardi-Goutières Syndrome.

Aicardi-Goutières syndrome is a genetic inflammatory disorder resulting in dispersed neurologic dysfunction. Despite a recognition of overall motor impairment, fine and visual motor skills are undercharacterized. We hypothesize that there is a spectrum of fine and visual motor skills in the Aicardi-Goutières syndrome population as captured by a standard outcome measure, the Peabody Developmental Motor Scales (PDMS-2), which will be proportional to overall disease severity.In a cohort of 74 subjects, the Peabody Developmental Motor Scales-2 grasping and visual-motor integration subtests were administered concurrently with the Aicardi-Goutières syndrome Severity Scale (severe [range 0-3], moderate [range 4-8], and attenuated [range 9-11]). The cohort was also compared by genotype and performance as defined by raw scores. The distribution of Peabody Developmental Motor Scales-2 scores within a genotype was assessed by interquartile ranges (IQRs).Peabody Developmental Motor Scales-2 grasping and visual-motor integration performance was the least variable in the TREX1-cohort (IQR: 10.00-12.00) versus the SAMHD1 and IFIH1 cohorts (IQR: 51.00-132.00 and 48.50-134.00, respectively). Neurologic severity highly correlated with both fine and visual motor skills (Spearman correlation: r = 0.87, 0.91, respectively). A floor effect (lowest 10% of possible scores) was observed within the severe cohort (n = 32/35), whereas a ceiling effect (top 10%) was observed in the attenuated cohort (n = 13/17).This study characterized the spectrum of fine and visual motor function in the Aicardi-Goutières syndrome population, which correlated with overall neurologic dysfunction. The Peabody Developmental Motor Scales-2 grasping and visual-motor integration showed promise as potential assessment tools in moderate and attenuated Aicardi-Goutières syndrome cohorts. A better understanding of fine and visual motor function in this population will benefit clinical care and clinical trial design.