Expanding the molecular landscape of childhood apraxia of speech: evidence from a single-center experience.

Background: Childhood apraxia of speech (CAS) is a genetically heterogeneous pediatric motor speech disorder. The advent of whole exome sequencing (WES) and whole genome sequencing techniques has led to increased identification of pathogenic variants in CAS genes. In an as yet uncharacterized Italian cohort, we aimed both to identify new pathogenic gene variants associated with CAS, and to confirm the disease-related role of genes already reported by others. We also set out to refine the clinical and neurodevelopmental characterization of affected children, with the aim of identifying specific, gene-related phenotypes. Methods: In a single-center study aiming to explore the genetic etiology of CAS in a cohort of 69 Italian children, WES was performed in the families of the 34 children found to have no copy number variants. Each of these families had only one child affected by CAS. Results: High-confidence (HC) gene variants were identified in 7/34 probands, in two of whom they affected KAT6A and CREBBP, thus confirming the involvement of these genes in speech impairment. The other probands carried variants in low-confidence (LC) genes, and 20 of these variants occurred in genes not previously reported as associated with CAS. UBA6, ZFHX4, and KAT6A genes were found to be more enriched in the CAS cohort compared to control individuals. Our results also showed that most HC genes are involved in epigenetic mechanisms and are expressed in brain regions linked to language acquisition processes. Conclusion: Our findings confirm a relatively high diagnostic yield in Italian patients.

Generation and Characterization of hiPS Lines from Three Patients Affected by Different Forms of HPDL-Related Neurological Disorders.

Hereditary spastic paraplegias are rare genetic disorders characterized by corticospinal tract impairment. Spastic paraplegia 83 (SPG83) is associated with biallelic mutations in the HPDL gene, leading to varied severities from neonatal to juvenile onset. The function of HPDL is unclear, though it is speculated to play a role in alternative coenzyme Q10 biosynthesis. Here, we report the generation of hiPS lines from primary skin fibroblasts derived from three SPG83 patients with different HPDL mutations, using episomal reprogramming. The patients' clinical characteristics are carefully listed. The hiPS lines were meticulously characterized, demonstrating typical pluripotent characteristics through immunofluorescence assays for stemness markers (OCT4, TRA1-60, NANOG, and SSEA4) and RT-PCR for endogenous gene expression. Genetic integrity and identity were confirmed via Sanger sequencing and short tandem repeat analysis. These hiPS cells displayed typical pluripotent characteristics and were able to differentiate into neocortical neurons via a dual SMAD inhibition protocol. In addition, HPDL mutant neurons assessed via long-term culturing were able to achieve effective maturation, similarly to their wild-type counterparts. The HPDL hiPS lines we generated will provide a valuable model for studying SPG83, offering insights into its molecular mechanisms and potential for developing targeted therapies.

Glucose metabolism impairment as a hallmark of progressive myoclonus epilepsies: a focus on neuronal ceroid lipofuscinoses.

Glucose is the brain's main fuel source, used in both energy and molecular production. Impaired glucose metabolism is associated with adult and pediatric neurodegenerative diseases such as Alzheimer's disease (AD), Parkinson's disease (PD), GLUT1 deficiency syndrome, and progressive myoclonus epilepsies (PMEs). PMEs, a group of neurological disorders typical of childhood and adolescence, account for 1% of all epileptic diseases in this population worldwide. Diffuse glucose hypometabolism is observed in the brains of patients affected by PMEs such as Lafora disease (LD), dentatorubral-pallidoluysian (DRPLA) atrophy, Unverricht-Lundborg disease (ULD), and myoclonus epilepsy with ragged red fibers (MERRFs). PMEs also include neuronal ceroid lipofuscinoses (NCLs), a subgroup in which lysosomal and autophagy dysfunction leads to progressive loss of vision, brain atrophy, and cognitive decline. We examine the role of impaired glucose metabolism in neurodegenerative diseases, particularly in the NCLs. Our literature review, which includes findings from case reports and animal studies, reveals that glucose hypometabolism is still poorly characterized both in vitro and in vivo in the different NCLs. Better identification of the glucose metabolism pathway impaired in the NCLs may open new avenues for evaluating the therapeutic potential of anti-diabetic agents in this population and thus raise the prospect of a therapeutic approach able to delay or even halt disease progression.

Charcot-Marie-Tooth type 2CC misdiagnosed as Chronic Inflammatory Demyelinating Polyradiculoneuropathy.

BACKGROUND AND AIMS: Charcot-Marie-Tooth (CMT) is a heterogeneous group of genetic neuropathies and is typically characterized by distal muscle weakness, sensory loss, pes cavus and areflexia. Herein we describe a case of CMT2CC presenting with proximal muscle weakness and equivocal electrophysiological features, that was misdiagnosed as chronic inflammatory demyelinating polyneuropathy (CIDP). CASE REPORT: A 30-year-old woman complained of proximal muscle weakness with difficulty climbing stairs. Neurological examination showed weakness in lower limb (LL) muscles, that was marked proximally and mild distally, and absence of deep tendon reflexes in the ankles. Nerve conduction studies (NCS) showed sensory-motor neuropathy with non-uniform NC velocity and a partial conduction block (CBs) in peroneal nerve and tibial nerves. Thus, a diagnosis of CIDP was entertained and the patient underwent ineffective treatment with intravenous immunoglobulins. At electrophysiological revaluation CB in peroneal nerve was undetectable as also distal CMAP had decreased whereas the CBs persisted in tibial nerves. Hypothesizing a hereditary neuropathy, we examined the proband's son, who presented mild weakness of distal and proximal muscles at lower limbs. Neurophysiological investigation showed findings consistent with an intermediate-axonal electrophysiological pattern. A targeted-NGS including 136 CMT genes showed the heterozygous frameshift mutation (c.3057dupG; p.K1020fs*43) in the NEFH gene, coding for the neurofilament heavy chain and causing CMT2CC. INTERPRETATION: Diagnosis of a genetic neuropathy may be challenging when clinical features are atypical and/or electrophysiological features are misleading. The most common misdiagnosis is CIDP. Our report suggests that also CMT2CC patients with proximal muscle weakness and equivocal electrophysiological features might be misdiagnosed as CIDP.

Pseudodominance in RFC1-Spectrum Disorder.

Cerebellar ataxia, neuropathy, vestibular areflexia syndrome (CANVAS) and disease spectrum is an autosomal recessive disorder associated with biallelic repeat expansion (RE) in the RFC1 gene. A high carrier frequency in the healthy population determines the possibility of having affected members in two consecutive generations. We describe pseudodominance in two families affected with RFC1 disorder (10 affected, 5 oligo/asymptomatic individuals). In Family A, after the 75-year-old index case was diagnosed with CANVAS, the 73-year-old wife decided to undergo screening for carrier testing. Although she did not report any symptoms, she resulted positive for the biallelic AAGGG RE thus leading to a diagnosis in the asymptomatic offspring as well and revealing a pseudodominant pattern of inheritance. In Family B pseudodominance was suspected after the identification of the RFC1 RE in the proband affected by sensitive neuropathy because of a positive family history for undetermined polyneuropathy in the mother. The post-mortem identification of the RFC1 RE in a sample specimen from the deceased mother, who had been under our care, allowed the solution of a "cold case". Our report suggests that pseudodominance is a confounding phenomenon to consider in RFC1-spectrum disorder and genetic counselling is instrumental in families with affected individuals.

Severe mitochondrial encephalomyopathy caused by de novo variants in OPA1 gene.

Background: Mitochondria adjust their shape in response to the different energetic and metabolic requirements of the cell, through extremely dynamic fusion and fission events. Several highly conserved dynamin-like GTPases are involved in these processes and, among those, the OPA1 protein is a key player in the fusion of inner mitochondrial membranes. Hundreds of monoallelic or biallelic pathogenic gene variants have been described in OPA1, all associated with a plethora of clinical phenotypes without a straightforward genotype-phenotype correlation. Methods: Here we report two patients harboring novel de novo variants in OPA1. DNA of two patients was analyzed using NGS technology and the pathogenicity has been evaluated through biochemical and morphological studies in patient's derived fibroblasts and in yeast model. Results: The two patients here reported manifest with neurological signs resembling Leigh syndrome, thus further expanding the clinical spectrum associated with variants in OPA1. In cultured skin fibroblasts we observed a reduced amount of mitochondrial DNA (mtDNA) and altered mitochondrial network characterized by more fragmented mitochondria. Modeling in yeast allowed to define the deleterious mechanism and the pathogenicity of the identified gene mutations. Conclusion: We have described two novel-single OPA1 mutations in two patients characterized by early-onset neurological signs, never documented, thus expanding the clinical spectrum of this complex syndrome. Moreover, both yeast model and patients derived fibroblasts showed mitochondrial defects, including decreased mtDNA maintenance, correlating with patients' clinical phenotypes.

CCDC78: Unveiling the Function of a Novel Gene Associated with Hereditary Myopathy.

CCDC78 was identified as a novel candidate gene for autosomal dominant centronuclear myopathy-4 (CNM4) approximately ten years ago. However, to date, only one family has been described, and the function of CCDC78 remains unclear. Here, we analyze for the first time a family harboring a CCDC78 nonsense mutation to better understand the role of CCDC78 in muscle. METHODS: We conducted a comprehensive histopathological analysis on muscle biopsies, including immunofluorescent assays to detect multiple sarcoplasmic proteins. We examined CCDC78 transcripts and protein using WB in CCDC78-mutated muscle tissue; these analyses were also performed on muscle, lymphocytes, and fibroblasts from healthy subjects. Subsequently, we conducted RT-qPCR and transcriptome profiling through RNA-seq to evaluate changes in gene expression associated with CCDC78 dysfunction in muscle. Lastly, coimmunoprecipitation (Co-Ip) assays and mass spectrometry (LC-MS/MS) studies were carried out on extracted muscle proteins from both healthy and mutated subjects. RESULTS: The histopathological features in muscle showed novel histological hallmarks, which included areas of dilated and swollen sarcoplasmic reticulum (SR). We provided evidence of nonsense-mediated mRNA decay (NMD), identified the presence of novel CCDC78 transcripts in muscle and lymphocytes, and identified 1035 muscular differentially expressed genes, including several involved in the SR. Through the Co-Ip assays and LC-MS/MS studies, we demonstrated that CCDC78 interacts with two key SR proteins: SERCA1 and CASQ1. We also observed interactions with MYH1, ACTN2, and ACTA1. CONCLUSIONS: Our findings provide insight, for the first time, into the interactors and possible role of CCDC78 in skeletal muscle, locating the protein in the SR. Furthermore, our data expand on the phenotype previously associated with CCDC78 mutations, indicating potential histopathological hallmarks of the disease in human muscle. Based on our data, we can consider CCDC78 as the causative gene for CNM4.

CACNA1G Causes Dominantly Inherited Myoclonus-Ataxia with Intellectual Disability: A Case Report.

Spinocerebellar ataxias (SCAs) are characterized by substantial phenotypic variability. Among them, SCA42 is a rare non-expansion entity presenting with slowly progressive cerebellar syndrome but whose clinical spectrum may be also wider. A 53-year-old male presented with progressive myoclonus-ataxia and intellectual disability. Genetic screening revealed a novel c.3835G > A (p. Asp1279Asn) variant in the CACNA1G gene. SCA42 is a rare non-expansion SCA caused by mutations in CACNA1G on chromosome 17q21, encoding the Ca(V)3.1, a low-threshold voltage-gated T-type calcium channel. The novel variant we identified is potentially involved in channel activity. This case expands the knowledge regarding CACNA1G-associated phenotype and highlights the importance of genetic screening in myoclonus-ataxia disorders.

Extracellular Vesicles Induce Nuclear Factor-κB Activation and Interleukin-8 Synthesis through miRNA-191-5p Contributing to Inflammatory Processes: Potential Implications in the Pathogenesis of Chronic Obstructive Pulmonary Disease.

Extracellular vesicles (EVs) play a pivotal role in a variety of physiologically relevant processes, including lung inflammation. Recent attention has been directed toward EV-derived microRNAs (miRNAs), such as miR-191-5p, particularly in the context of inflammation. Here, we investigated the impact of miR-191-5p-enriched EVs on the activation of NF-κB and the expression of molecules associated with inflammation such as interleukin-8 (IL-8). To this aim, cells of bronchial epithelial origin, 16HBE, were transfected with miR-191-5p mimic and inhibitor and subsequently subjected to stimulations to generate EVs. Then, bronchial epithelial cells were exposed to the obtained EVs to evaluate the activation of NF-κB and IL-8 levels. Additionally, we conducted a preliminary investigation to analyze the expression profiles of miR-191-5p in EVs isolated from the plasma of patients diagnosed with chronic obstructive pulmonary disease (COPD). Our initial findings revealed two significant observations. First, the exposure of bronchial epithelial cells to miR-191-5p-enriched EVs activated the NF-kB signaling and increased the synthesis of IL-8. Second, we discovered the presence of miR-191-5p in peripheral blood-derived EVs from COPD patients and noted a correlation between miR-191-5p levels and inflammatory and functional parameters. Collectively, these data corroborate and further expand the proinflammatory role of EVs, with a specific emphasis on miR-191-5p as a key cargo involved in this process. Consequently, we propose a model in which miR-191-5p, carried by EVs, plays a role in airway inflammation and may contribute to the pathogenesis of COPD.

Combined generalized and focal epilepsy with reflex features in Adaptor protein complex 4-associated hereditary spastic paraplegias: A cohort observational study.

BACKGROUND: Patients with genetic deficiency of the adaptor protein complex 4 (AP-4) exhibit earlyonset developmental delay, spastic diplegia, intellectual disability, speech impairment. The phenotype overlaps with other hereditary spastic paraplegias and cerebral palsies. Febrile seizures are common at onset. Epilepsy has been described in more than half of cases, arising in early infancy often with status epilepticus, but no typical seizure semiology or electroencephalographic features have been identified thus far. PURPOSE: We aimed to specifically investigate the epileptological characteristics of the syndrome to unveil possible biomarkers of seizure development and prognosis in AP-4 deficiency. METHODS: Observational cohort study on patients with bi-allelic pathogenic variants in AP-4 subunits and epilepsy. We focused on the seizure semiology, electroencephalographic characteristics and response to antiseizure medications. RESULTS: Patients harboured pathogenic variants in AP4S1 (n = 5) or AP4M1 (n = 1). The phenotype included spastic paraparesis, intellectual disability, speech/language impairment, microcephaly, and MRI evidence of hypoplasia of the corpus callosum. In 66 % of the patients, febrile seizures preceded the onset of epilepsy, which spanned from infancy to adolescence (range=14 months-13 years). Absences (66 %) and focal motor seizures (50 %) were common. No patient met the criteria for drug-resistance. Peculiar electroencephalographic features arose after the epilepsy onset and persisted at long-term follow-up: bilateral and asynchronous focal discharges combined with independent diffuse spike-wave-discharges (100 %) and reflex abnormalities (66 %). CONCLUSION: In AP-4 complex disease, epilepsy could arise beyond early infancy, until adolescence, with variable combination of generalized and focal seizures. The prognosis was favourable. We observed a common electroencephalographic signature - combined focal/generalized and reflex abnormalities - which may constitute a biomarker of AP-4 deficiency with epilepsy, applicable to inform genetic testing and disentangle the differential diagnosis.

Children and Young Adults with Epilepsy Exhibit an Interictal Autonomic Dysfunction: A Prospective Exploratory Study.

Dysautonomic disorders are an increasingly studied group of conditions, either as isolated diseases or associated with other neurological disorders. There is growing interest in understanding how dysautonomia affects people with epilepsy, who may report autonomic symptoms before, during and after seizures. Furthermore, autonomic abnormalities appear to play a role in sudden unexpected death in epilepsy, likely contributing to the increased mortality rate described in epilepsy. To better understand the association between epilepsy and dysautonomia, we explored electrochemical skin conductance in a group of 18 children and young adults with epilepsy compared to 15 age- and sex-matched healthy controls by the SudoscanTM test. We found a significant difference in terms of electrochemical skin conductance, suggesting that people with epilepsy suffer significantly reduced conductance in small nerve fibers. Within patients, values were significantly different according to the type of epilepsy and to neuroimaging results, with lower conductance values in epilepsies of unknown origin and in patients with morphological abnormalities of the brain. Using a non-invasive test, we identified altered conductance of small sympathetic nerve fibers in children and young adults with epilepsy, suggesting underlying dysautonomia. Further studies are needed to investigate this association and to clarify its neurobiological substrates.

Convolutional Neural Network-Based Automated Segmentation of Skeletal Muscle and Subcutaneous Adipose Tissue on Thigh MRI in Muscular Dystrophy Patients.

We aim to develop a deep learning-based algorithm for automated segmentation of thigh muscles and subcutaneous adipose tissue (SAT) from T1-weighted muscle MRIs from patients affected by muscular dystrophies (MDs). From March 2019 to February 2022, adult and pediatric patients affected by MDs were enrolled from Azienda Ospedaliera Universitaria Pisana, Pisa, Italy (Institution 1) and the IRCCS Stella Maris Foundation, Calambrone-Pisa, Italy (Institution 2), respectively. All patients underwent a bilateral thighs MRI including an axial T1 weighted in- and out-of-phase (dual-echo). Both muscles and SAT were manually and separately segmented on out-of-phase image sets by a radiologist with 6 years of experience in musculoskeletal imaging. A U-Net1 and U-Net3 were built to automatically segment the SAT, all the thigh muscles together and the three muscular compartments separately. The dataset was randomly split into the on train, validation, and test set. The segmentation performance was assessed through the Dice similarity coefficient (DSC). The final cohort included 23 patients. The estimated DSC for U-Net1 was 96.8%, 95.3%, and 95.6% on train, validation, and test set, respectively, while the estimated accuracy for U-Net3 was 94.1%, 92.9%, and 93.9%. Both of the U-Nets achieved a median DSC of 0.95 for SAT segmentation. The U-Net1 and the U-Net3 achieved an optimal agreement with manual segmentation for the automatic segmentation. The so-developed neural networks have the potential to automatically segment thigh muscles and SAT in patients affected by MDs.

Proteomics and lipidomic analysis reveal dysregulated pathways associated with loss of sacsin.

Introduction: Autosomal recessive spastic ataxia of Charlevoix-Saguenay (ARSACS) is a rare incurable neurodegenerative disease caused by mutations in the SACS gene, which codes for sacsin, a large protein involved in protein homeostasis, mitochondrial function, cytoskeletal dynamics, autophagy, cell adhesion and vesicle trafficking. However, the pathogenic mechanisms underlying sacsin dysfunction are still largely uncharacterized, and so attempts to develop therapies are still in the early stages. Methods: To achieve further understanding of how processes are altered by loss of sacsin, we used untargeted proteomics to compare protein profiles in ARSACS fibroblasts versus controls. Results: Our analyses confirmed the involvement of known biological pathways and also implicated calcium and lipid homeostasis in ARSACS skin fibroblasts, a finding further verified in SH-SY5Y SACS -/- cells. Validation through mass spectrometry-based analysis and comparative quantification of lipids by LC-MS in fibroblasts revealed increased levels of ceramides coupled with a reduction of diacylglycerols. Discussion: In addition to confirming aberrant Ca2+ homeostasis in ARSACS, this study described abnormal lipid levels associated with loss of sacsin.

Generation of a human induced pluripotent stem cell line (FSMi001-A) from fibroblasts of a patient carrying heterozygous mutation in the REEP1 gene.

Hereditary spastic paraplegias (HSPs) a group of rare, clinically, and genetically heterogeneous disorders characterized by progressive degeneration of the corticospinal tract. Among these HSPs, SPG31 is due to autosomal dominant mutations in the receptor expression-enhancing protein 1 (REEP1) gene. Over 80 genes have been associated with HSPs, and the list is constantly growing as research progresses. This study is aimed to create a patient-derived human induced pluripotent stem cell (hiPSC) line with a specific nonsense mutation to better characterize the etiopathogenesis of the disease.

An MRI evaluation of white matter involvement in paradigmatic forms of spastic ataxia: results from the multi-center PROSPAX study.

BACKGROUND: Autosomal Recessive Spastic Ataxia of Charlevoix-Saguenay (ARSACS) and Spastic Paraplegia Type 7 (SPG7) are paradigmatic spastic ataxias (SPAX) with suggested white matter (WM) involvement. Aim of this work was to thoroughly disentangle the degree of WM involvement in these conditions, evaluating both macrostructure and microstructure via the analysis of diffusion MRI (dMRI) data. MATERIAL AND METHODS: In this multi-center prospective study, ARSACS and SPG7 patients and Healthy Controls (HC) were enrolled, all undergoing a standardized dMRI protocol and a clinimetrics evaluation including the Scale for the Assessment and Rating of Ataxia (SARA). Differences in terms of WM volume or global microstructural WM metrics were probed, as well as the possible occurrence of a spatially defined microstructural WM involvement via voxel-wise analyses, and its correlation with patients' clinical status. RESULTS: Data of 37 ARSACS (M/F = 21/16; 33.4 ± 12.4 years), 37 SPG7 (M/F = 24/13; 55.7 ± 10.7 years), and 29 HC (M/F = 13/16; 42.1 ± 17.2 years) were analyzed. While in SPG7, only a mild mean microstructural damage was found compared to HC, ARSACS patients present a severe WM involvement, with a reduced global volume (p < 0.001), an alteration of all microstructural metrics (all with p < 0.001), without a spatially defined pattern of damage but with a prominent involvement of commissural fibers. Finally, in ARSACS, a correlation between microstructural damage and SARA scores was found (p = 0.004). CONCLUSION: In ARSACS, but not SPG7 patients, we observed a complex and multi-faced involvement of brain WM, with a clinically meaningful widespread loss of axonal and dendritic integrity, secondary demyelination and, overall, a reduction in cellularity and volume.

SCAR32: Functional characterization and expansion of the clinical-genetic spectrum.

OBJECTIVE: Biallelic mutations in PRDX3 have been linked to autosomal recessive spinocerebellar ataxia type 32. In this study, which aims to contribute to the growing body of knowledge on this rare disease, we identified two unrelated patients with mutations in PRDX3. We explored the impact of PRDX3 mutation in patient skin fibroblasts and the role of the gene in neurodevelopment. METHODS: We performed trio exome sequencing that identified mutations in PRDX3 in two unrelated patients. We also performed functional studies in patient skin fibroblasts and generated a "crispant" zebrafish (Danio rerio) model to investigate the role of the gene during nervous system development. RESULTS: Our study reports two additional patients. Patient 1 is a 19-year-old male who showed a novel homozygous c.525_535delGTTAGAAGGTT (p. Leu176TrpfsTer11) mutation as the genetic cause of cerebellar ataxia. Patient 2 is a 20-year-old male who was found to present the known c.425C>G/p. Ala142Gly variant in compound heterozygosity with the p. Leu176TrpfsTer11 one. While the fibroblast model failed to recapitulate the pathological features associated with PRDX3 loss of function, our functional characterization of the prdx3 zebrafish model revealed motor defects, increased susceptibility to reactive oxygen species-triggered apoptosis, and an impaired oxygen consumption rate. CONCLUSIONS: We identified a new variant, thereby expanding the genetic spectrum of PRDX3-related disease. We developed a novel zebrafish model to investigate the consequences of prdx3 depletion on neurodevelopment and thus offered a potential new tool for identifying new treatment opportunities.

MRI-ARSACS: An Imaging Index for Autosomal Recessive Spastic Ataxia of Charlevoix-Saguenay (ARSACS) Identification Based on the Multicenter PROSPAX Study.

BACKGROUND: Autosomal recessive spastic ataxia of Charlevoix-Saguenay (ARSACS) and hereditary spastic paraplegia type 7 (SPG7) represent the most common genotypes of spastic ataxia (SPAX). To date, their magnetic resonance imaging (MRI) features have only been described qualitatively, and a pure neuroradiological differential diagnosis between these two conditions is difficult to achieve. OBJECTIVES: To test the performance of MRI measures to discriminate between ARSACS and SPG7 (as an index of common SPAX disease). METHODS: In this prospective multicenter study, 3D-T1-weighted images of 59 ARSACS (35.4 ± 10.3 years, M/F = 33/26) and 78 SPG7 (54.8 ± 10.3 years, M/F = 51/27) patients of the PROSPAX Consortium were analyzed, together with 30 controls (45.9 ± 16.9 years, M/F = 15/15). Different linear and surface measures were evaluated. A receiver operating characteristic analysis was performed, calculating area under the curve (AUC) and corresponding diagnostic accuracy parameters. RESULTS: The pons area proved to be the only metric increased exclusively in ARSACS patients (P = 0.02). Other different measures were reduced in ARSACS and SPG7 compared with controls (all with P ≤ 0.005). A cut-off value equal to 1.67 of the pons-to-superior vermis area ratio proved to have the highest AUC (0.98, diagnostic accuracy 93%, sensitivity 97%) in discriminating between ARSACS and SPG7. CONCLUSIONS: Evaluation of the pons-to-superior vermis area ratio can discriminate ARSACS from other SPAX patients, as exemplified here by SPG7. Hence, we hereby propose this ratio as the Magnetic Resonance Index for the Assessment and Recognition of patients harboring SACS mutations (MRI-ARSACS), a novel diagnostic tool able to identify ARSACS patients and useful for discriminating ARSACS from other SPAX patients undergoing MRI. © 2024 International Parkinson and Movement Disorder Society.

Non-Specific Epileptic Activity, EEG, and Brain Imaging in Loss of Function Variants in SATB1: A New Case Report and Review of the Literature.

SATB1 (MIM #602075) is a relatively new gene reported only in recent years in association with neurodevelopmental disorders characterized by variable facial dysmorphisms, global developmental delay, poor or absent speech, altered electroencephalogram (EEG), and brain abnormalities on imaging. To date about thirty variants in forty-four patients/children have been described, with a heterogeneous spectrum of clinical manifestations. In the present study, we describe a new patient affected by mild intellectual disability, speech disorder, and non-specific abnormalities on EEG and neuroimaging. Family studies identified a new de novo frameshift variant c.1818delG (p.(Gln606Hisfs*101)) in SATB1. To better define genotype-phenotype associations in the different types of reported SATB1 variants, we reviewed clinical data from our patient and from the literature and compared manifestations (epileptic activity, EEG abnormalities and abnormal brain imaging) due to missense variants versus those attributable to loss-of-function/premature termination variants. Our analyses showed that the latter variants are associated with less severe, non-specific clinical features when compared with the more severe phenotypes due to missense variants. These findings provide new insights into SATB1-related disorders.