Clinical and Molecular Spectrum of Autosomal Recessive CA8-Related Cerebellar Ataxia

BACKGROUND

Based on a limited number of reported families, biallelic CA8 variants have currently been associated with a recessive neurological disorder named, cerebellar ataxia, mental retardation, and dysequilibrium syndrome 3 (CAMRQ-3).

OBJECTIVES

We aim to comprehensively investigate CA8-related disorders (CA8-RD) by reviewing existing literature and exploring neurological, neuroradiological, and molecular observations in a cohort of newly identified patients.

METHODS

We analyzed the phenotype of 27 affected individuals from 14 families with biallelic CA8 variants (including data from 15 newly identified patients from eight families), ages 4 to 35 years. Clinical, genetic, and radiological assessments were performed, and zebrafish models with ca8 knockout were used for functional analysis.

RESULTS

Patients exhibited varying degrees of neurodevelopmental disorders (NDD), along with predominantly progressive cerebellar ataxia and pyramidal signs and variable bradykinesia, dystonia, and sensory impairment. Quadrupedal gait was present in only 10 of 27 patients. Progressive selective cerebellar atrophy, predominantly affecting the superior vermis, was a key diagnostic finding in all patients. Seven novel homozygous CA8 variants were identified. Zebrafish models demonstrated impaired early neurodevelopment and motor behavior on ca8 knockout.

CONCLUSION

Our comprehensive analysis of phenotypic features indicates that CA8-RD exhibits a wide range of clinical manifestations, setting it apart from other subtypes within the category of CAMRQ. CA8-RD is characterized by cerebellar atrophy and should be recognized as part of the autosomal-recessive cerebellar ataxias associated with NDD. Notably, the presence of progressive superior vermis atrophy serves as a valuable diagnostic indicator. © 2024 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.

Biallelic variation in the choline and ethanolamine transporter FLVCR1 underlies a pleiotropic disease spectrum from adult neurodegeneration to severe developmental disorders

FLVCR1 encodes Feline leukemia virus subgroup C receptor 1 (FLVCR1), a solute carrier (SLC) transporter within the Major Facilitator Superfamily. FLVCR1 is a widely expressed transmembrane protein with plasma membrane and mitochondrial isoforms implicated in heme, choline, and ethanolamine transport. While Flvcr1 knockout mice die in utero with skeletal malformations and defective erythropoiesis reminiscent of Diamond-Blackfan anemia, rare biallelic pathogenic FLVCR1 variants are linked to childhood or adult-onset neurodegeneration of the retina, spinal cord, and peripheral nervous system. We ascertained from research and clinical exome sequencing 27 individuals from 20 unrelated families with biallelic ultra-rare missense and predicted loss-of-function (pLoF) FLVCR1 variant alleles. We characterize an expansive FLVCR1 phenotypic spectrum ranging from adult-onset retinitis pigmentosa to severe developmental disorders with microcephaly, reduced brain volume, epilepsy, spasticity, and premature death. The most severely affected individuals, including three individuals with homozygous pLoF variants, share traits with Flvcr1 knockout mice and Diamond-Blackfan anemia including macrocytic anemia and congenital skeletal malformations. Pathogenic FLVCR1 missense variants primarily lie within transmembrane domains and reduce choline and ethanolamine transport activity compared with wild-type FLVCR1 with minimal impact on FLVCR1 stability or subcellular localization. Several variants disrupt splicing in a mini-gene assay which may contribute to genotype-phenotype correlations. Taken together, these data support an allele-specific gene dosage model in which phenotypic severity reflects residual FLVCR1 activity. This study expands our understanding of Mendelian disorders of choline and ethanolamine transport and demonstrates the importance of choline and ethanolamine in neurodevelopment and neuronal homeostasis.

Variants in DOK7 results in fetal akinesia deformation sequence: A case report and review of literature

We report the third case of FADS due to biallelic DOK7 variants, which further strengthens the association of DOK7 with this lethal phenotype and lack of genotype phenotype correlation.

Landscape of genetic infantile epileptic spasms syndrome-A multicenter cohort of 124 children from India

OBJECTIVE

Literature on the genotypic spectrum of Infantile Epileptic Spasms Syndrome (IESS) in children is scarce in developing countries. This multicentre collaboration evaluated the genotypic and phenotypic landscape of genetic IESS in Indian children.

METHODS

Between January 2021 and June 2022, this cross-sectional study was conducted at six centers in India. Children with genetically confirmed IESS, without definite structural-genetic and structural-metabolic etiology, were recruited and underwent detailed in-person assessment for phenotypic characterization. The multicentric data on the genotypic and phenotypic characteristics of genetic IESS were collated and analyzed.

RESULTS

Of 124 probands (60% boys, history of consanguinity in 15%) with genetic IESS, 105 had single gene disorders (104 nuclear and one mitochondrial), including one with concurrent triple repeat disorder (fragile X syndrome), and 19 had chromosomal disorders. Of 105 single gene disorders, 51 individual genes (92 variants including 25 novel) were identified. Nearly 85% of children with monogenic nuclear disorders had autosomal inheritance (dominant-55.2%, recessive-14.2%), while the rest had X-linked inheritance. Underlying chromosomal disorders included trisomy 21 (n = 14), Xq28 duplication (n = 2), and others (n = 3). Trisomy 21 (n = 14), ALDH7A1 (n = 10), SCN2A (n = 7), CDKL5 (n = 6), ALG13 (n = 5), KCNQ2 (n = 4), STXBP1 (n = 4), SCN1A (n = 4), NTRK2 (n = 4), and WWOX (n = 4) were the dominant single gene causes of genetic IESS. The median age at the onset of epileptic spasms (ES) and establishment of genetic diagnosis was 5 and 12 months, respectively. Pre-existing developmental delay (94.3%), early age at onset of ES (<6 months; 86.2%), central hypotonia (81.4%), facial dysmorphism (70.1%), microcephaly (77.4%), movement disorders (45.9%) and autistic features (42.7%) were remarkable clinical findings. Seizures other than epileptic spasms were observed in 83 children (66.9%). Pre-existing epilepsy syndrome was identified in 21 (16.9%). Nearly 60% had an initial response to hormonal therapy.

SIGNIFICANCE

Our study highlights a heterogenous genetic landscape and phenotypic pleiotropy in children with genetic IESS.

Clinical, neuroradiological, and molecular characterization of mitochondrial threonyl-tRNA-synthetase (TARS2)-related disorder

PURPOSE

Biallelic variants in TARS2, encoding the mitochondrial threonyl-tRNA-synthetase, have been reported in a small group of individuals displaying a neurodevelopmental phenotype but with limited neuroradiological data and insufficient evidence for causality of the variants.

METHODS

Exome or genome sequencing was carried out in 15 families. Clinical and neuroradiological evaluation was performed for all affected individuals, including review of 10 previously reported individuals. The pathogenicity of TARS2 variants was evaluated using in vitro assays and a zebrafish model.

RESULTS

We report 18 new individuals harboring biallelic TARS2 variants. Phenotypically, these individuals show developmental delay/intellectual disability, regression, cerebellar and cerebral atrophy, basal ganglia signal alterations, hypotonia, cerebellar signs, and increased blood lactate. In vitro studies showed that variants within the TARS2301-381 region had decreased binding to Rag GTPases, likely impairing mTORC1 activity. The zebrafish model recapitulated key features of the human phenotype and unraveled dysregulation of downstream targets of mTORC1 signaling. Functional testing of the variants confirmed the pathogenicity in a zebrafish model.

CONCLUSION

We define the clinico-radiological spectrum of TARS2-related mitochondrial disease, unveil the likely involvement of the mTORC1 signaling pathway as a distinct molecular mechanism, and establish a TARS2 zebrafish model as an important tool to study variant pathogenicity.

Mitochondrial Complex I Deficiency Masquerading as Stroke-Like Episode Clinically and as Alexander Disease Radiologically Following Chicken Pox

Mitochondrial disorders are a group of metabolic disorders with variable presentation and usually affect organs with high energy requirements like the brain, eye, and heart. Seventeen-month-old girl child presented with right hemiparesis and regression of milestones following chicken pox. Investigations showed elevated lactate, white matter signal changes in both periventricular and subcortical white matter with frontal predominance in the MRI of the brain, cardiomyopathy in the echocardiography, with complex I deficiency in respiratory enzyme assay in the muscle biopsy. A homozygous missense variant c.304C>T (p. Arg102Cys) in exon 5 of NDUFS8 gene (chr11:67800682C>T; NM_002496.4) was detected on whole exome sequencing with positive parental Sanger for the same gene. The child was started on a mitochondrial cocktail, ramipril, and frusemide. Mitochondrial complex deficiency should be considered in cases with stroke-like episodes, and predominant white matter involvement on imaging mimicking classical genetic leukodystrophy like Alexander disease.

Pure cerebellar ataxia due to bi-allelic PRDX3 variants including recurring p.Asp202Asn

Bi-allelic variants in peroxiredoxin 3 (PRDX3) have only recently been associated with autosomal recessive spinocerebellar ataxia characterized by early onset slowly progressive cerebellar ataxia, variably associated with hyperkinetic and hypokinetic features, accompanied by cerebellar atrophy and occasional olivary and brainstem involvement. Herein, we describe a further simplex case carrying a reported PRDX3 variant as well as two additional cases with novel variants. We report the first Brazilian patient with SCAR32, replicating the pathogenic status of a known variant. All presented cases from the Brazilian and Indian populations expand the phenotypic spectrum of the disease by displaying prominent neuroradiological findings. SCAR32, although rare, should be included in the differential diagnosis of sporadic or recessive childhood and adolescent-onset pure and complex cerebellar ataxia.

Case Series of Ethylmalonic Encephalopathy from Southern India

Ethylmalonic encephalopathy is a rare neurometabolic disorder with central nervous system involvement and vasculopathy. It is presented in infancy with developmental delay, acrocyanosis, petechiae, chronic diarrhea, and early death. This was a retrospective study of confirmed cases of ethylmalonic aciduria from a tertiary care hospital over a period of 5 years from January 2015 to December 2020. Case details including analysis of clinical history, investigations, and outcomes are presented. Of six cases, male-to-female ratio was 4:2. Mean age of presentation was 35.5 months (range: 14-83 months). Consanguinity, global developmental delay, failure to thrive, skin rashes, microcephaly, hypotonia, and exaggerated deep tendon reflexes were observed in all cases. Chronic diarrhea was presented in five cases. The serum levels of C4 carnitine and urinary levels of ethylmalonic acid were increased in all cases. Magnetic resonance imaging (MRI) of the brain showed heterogenous bilateral symmetrical changes in the basal ganglia in five cases, and in one case, MRI could not be done. Genetic testing in two cases showed a homozygous variant in ETHE1 gene. Four children died, while the other two cases showed a decreased in recurrent encephalopathies and diarrhea after starting metronidazole. All children had global developmental delay, failure to thrive, skin rashes, central hypotonia, increased C4 carnitine levels in the serum, and increased ethylmalonic acid in the urine. Chronic diarrhea, acrocyanosis, and basal ganglia change in the MRI of the brain also give important clues for diagnosis. Metronidazole is useful in preventing recurrent episodes of encephalopathy.

A novel biallelic frameshift variant in C2orf69 causing developmental regression, seizures, microcephaly, autistic features, and hypertonia

Combined oxidative phosphorylation deficiency type 53 (COXPD53) is an autosomal recessive neurodevelopmental disorder (NDD) caused by homozygous variants in the gene C2orf69. Here, we report a novel frameshift variant c.187_191dupGCCGA, p.D64Efs*56 identified in an individual with clinical presentation of COXPD53 with developmental regression and autistic features. The variant c.187_191dupGCCGA, p.D64Efs*56 represents the most N-terminal part of C2orf69. Notable clinical features of COXPD53of the proband include developmental delay, developmental regression, seizures, microcephaly, and hypertonia. Structural brain defects of cerebral atrophy, cerebellar atrophy, hypomyelination, and thin corpus callosum were also observed. While we observe strong phenotypic overlap among affected individuals with C2orf69 variants, developmental regression and autistic features have not been previously described in individuals with COXPD53. Together, this case expands the genetic and clinical phenotypic spectrum of C2orf69-associated COXPD53.

Infantile Systemic Hyalinosis Presenting as Pseudo-Paralysis in Infancy: Study of Six Cases

Infantile systemic hyalinosis is a very rare fatal autosomal recessive genetic disorder with a mutation in capillary morphogenesis gene-2- CMG2 /Human anthrax toxin-2 ANTXR2 resulting in spindle cell proliferation, altered collagen metabolism along with extensive deposition of hyaline material in the skin and several tissues. To date only a few cases have been reported in the literature, hence we reported this series. This study is a retrospective chart review of infants diagnosed with infantile systemic hyalinosis from January 2015 through December 2020 at a tertiary care children's hospital in South India. The mean age of presentation was 9.4 months, with a male to female ratio of 1:5. All children were born of consanguineous marriage except one child. All children had symptoms at birth, painful limb movements, multiple joint stiffness, gingival thickening, skin lesions around perianal, perioral areas, and frog-like position. Three (50%) children had stiff skin. Routine tests including complete blood count, liver function test, renal function test, creatine phosphokinase, nerve conduction studies, and metabolic tests were normal in all children. Skin biopsy showed hyalinized collagenous tissue in the dermis. Genetic study results of two cases revealed pathogenic variants in ANTXR2 gene. Infantile systemic hyalinosis should be considered in infants presenting with painful limb movements. The diagnosis helped in avoiding unnecessary investigations and prognostications. The genetic information from proband mutation helped in prenatal diagnosis in two families.

Snijders Blok-Campeau Syndrome: Description of 20 Additional Individuals with Variants in CHD3 and Literature Review

Snijders Blok-Campeau syndrome (SNIBCPS, OMIM# 618205) is an extremely infrequent disease with only approximately 60 cases reported so far. SNIBCPS belongs to the group of neurodevelopmental disorders (NDDs). Clinical features of patients with SNIBCPS include global developmental delay, intellectual disability, speech and language difficulties and behavioral disorders like autism spectrum disorder. In addition, patients with SNIBCPS exhibit typical dysmorphic features including macrocephaly, hypertelorism, sparse eyebrows, broad forehead, prominent nose and pointed chin. The severity of the neurological effects as well as the presence of other features is variable among subjects. SNIBCPS is caused likely by pathogenic and pathogenic variants in CHD3 (Chromodomain Helicase DNA Binding Protein 3), which seems to be involved in chromatin remodeling by deacetylating histones. Here, we report 20 additional patients with clinical features compatible with SNIBCPS from 17 unrelated families with confirmed likely pathogenic/pathogenic variants in CHD3. Patients were analyzed by whole exome sequencing and segregation studies were performed by Sanger sequencing. Patients in this study showed different pathogenic variants affecting several functional domains of the protein. Additionally, none of the variants described here were reported in control population databases, and most computational predictors suggest that they are deleterious. The most common clinical features of the whole cohort of patients are global developmental delay (98%) and speech disorder/delay (92%). Other frequent features (51-74%) include intellectual disability, hypotonia, hypertelorism, abnormality of vision, macrocephaly and prominent forehead, among others. This study expands the number of individuals with confirmed SNIBCPS due to pathogenic or likely pathogenic variants in CHD3. Furthermore, we add evidence of the importance of the application of massive parallel sequencing for NDD patients for whom the clinical diagnosis might be challenging and where deep phenotyping is extremely useful to accurately manage and follow up the patients.

Genotype-phenotype correlations in RHOBTB2-associated neurodevelopmental disorders

PURPOSE

Missense variants clustering in the BTB domain region of RHOBTB2 cause a developmental and epileptic encephalopathy with early-onset seizures and severe intellectual disability.

METHODS

By international collaboration, we assembled individuals with pathogenic RHOBTB2 variants and a variable spectrum of neurodevelopmental disorders. By western blotting, we investigated the consequences of missense variants in vitro.

RESULTS

In accordance with previous observations, de novo heterozygous missense variants in the BTB domain region led to a severe developmental and epileptic encephalopathy in 16 individuals. Now, we also identified de novo missense variants in the GTPase domain in 6 individuals with apparently more variable neurodevelopmental phenotypes with or without epilepsy. In contrast to variants in the BTB domain region, variants in the GTPase domain do not impair proteasomal degradation of RHOBTB2 in vitro, indicating different functional consequences. Furthermore, we observed biallelic splice-site and truncating variants in 9 families with variable neurodevelopmental phenotypes, indicating that complete loss of RHOBTB2 is pathogenic as well.

CONCLUSION

By identifying genotype-phenotype correlations regarding location and consequences of de novo missense variants in RHOBTB2 and by identifying biallelic truncating variants, we further delineate and expand the molecular and clinical spectrum of RHOBTB2-related phenotypes, including both autosomal dominant and recessive neurodevelopmental disorders.

Endovascular Treatment of Cerebrovascular Lesions Using Nickel- or Nitinol-Containing Devices in Patients with Nickel Allergies

Nickel is used in many cerebral endovascular treatment devices. However, nickel hypersensitivity is the most common metal allergy, and the relative risk of treatment in these patients is unknown. This retrospective analysis identified patients with nickel or metal allergies who underwent cerebral endovascular treatment with nickel-containing devices. Seven patients with nickel and/or other metal allergies underwent treatment with 9 nickel-containing devices. None experienced periprocedural complications. No patient received treatment with corticosteroids or antihistamines. At a mean clinical follow-up for all patients of 22.8 months (range, 10.5-38.0 months), no patients had symptoms attributable to nickel allergic reactions. The mean radiographic follow-up for all patients at 18.4 months (range, 2.5-37.5 months) showed successful treatment of the targeted vascular pathologies, with no evidence of in-stent stenosis or other allergic or hypersensitivity sequelae. The treatment of cerebrovascular lesions with a nickel-containing device resulted in no adverse outcomes among these patients and was safe and effective.

Biotinidase Deficiency in the Second Decade with Atypical Neuroimaging Findings

Biotinidase deficiency is a rare autosomal recessive neurometabolic disorder resulting in biotin deficiency. Our patient presented with seizures and developmental delay since infancy and was started on megavitamin supplements. At 14 years, she presented with motor regression with encephalopathy after discontinuation of vitamins. There were no skin and hair changes. Magnetic resonance imaging (MRI) of the brain showed bilateral symmetrical posterior putamen signal changes. Tandem mass spectroscopy showed increased methyl malonyl carnitine and 3-OH isovaleryl carnitine. There was a low biotinidase level, and a pathogenic variant in the BTD gene in the next-generation sequencing was identified. Special importance is placed on the unusual symmetric posterior putamen involvement seen in MRI of the brain.

In Silico Characterization of RNASEH2A Pathogenic Variants and Identification of Novel Splice Site Donor Variant c.549+1G>T in Indian Population

Background Aicardi-Goutieres syndrome (AGS) is a genetic disorder that has variable manifestations including neurological, immunological, and sometimes other system involvement in various combinations. Considering the high genetic and clinical diversity of AGS and the importance of RNASEH2 complex in the biological system, it is important to take a systematic approach to delineate the genetic diagnosis and impact of missense mutations. Methods Clinical targeted gene sequencing followed by Sanger validation was performed in an individual with the clinical features of AGS. Protein modeling studies of all the reported RNASEH2A missense variants till date were performed using freely available web servers BioGrid, ShinyGO. Protein structures were visualized using Pymol. Results and discussion We identified a novel homozygous splice site donor variant c.549+1G>T in RNASEH2A. Furthermore protein-interactome studies identifiedpotential genetic interactors that include RNASEH2A, RNASEH2B, TYMS, RNASEH2C, RPA1, ORC3, ORC2, CDC6, PCNA, LIG1, PRIM1, RFC2, DUT, GINS1, MCM7, FEN1, MCM4, GINS2, CDK4, and MCM5. Identified genes were mapped to specific pathways using SHINY GO. DNA replication and cell cycle, centrosome cycle, post-replication repair, nucleic acid and metabolic process, cellular response to stress, DNA metabolic process, nucleic acid phosphodiester bond hydrolysis, RNA phosphodiester bond hydrolysis, and DNA biosynthetic process were identified as the linked pathways with the prioritized genes. Conclusion In conclusion, a sophisticated genotype and phenotype correlation followed by linking the genes to the key biological pathways opens new avenues to understand disease pathology and plan for therapeutic interventions.

CERT1 mutations perturb human development by disrupting sphingolipid homeostasis

Neural differentiation, synaptic transmission, and action potential propagation depend on membrane sphingolipids, whose metabolism is tightly regulated. Mutations in the ceramide transporter CERT (CERT1), which is involved in sphingolipid biosynthesis, are associated with intellectual disability, but the pathogenic mechanism remains obscure. Here, we characterize 31 individuals with de novo missense variants in CERT1. Several variants fall into a previously uncharacterized dimeric helical domain that enables CERT homeostatic inactivation, without which sphingolipid production goes unchecked. The clinical severity reflects the degree to which CERT autoregulation is disrupted, and inhibiting CERT pharmacologically corrects morphological and motor abnormalities in a Drosophila model of the disease, which we call ceramide transporter (CerTra) syndrome. These findings uncover a central role for CERT autoregulation in the control of sphingolipid biosynthetic flux, provide unexpected insight into the structural organization of CERT, and suggest a possible therapeutic approach for patients with CerTra syndrome.

Brain monoamine vesicular transport disease caused by homozygous SLC18A2 variants: A study in 42 affected individuals

PURPOSE

Brain monoamine vesicular transport disease is an infantile-onset movement disorder that mimics cerebral palsy. In 2013, the homozygous SLC18A2 variant, p.Pro387Leu, was first reported as a cause of this rare disorder, and dopamine agonists were efficient for treating affected individuals from a single large family. To date, only 6 variants have been reported. In this study, we evaluated genotype-phenotype correlations in individuals with biallelic SLC18A2 variants.

METHODS

A total of 42 affected individuals with homozygous SLC18A2 variant alleles were identified. We evaluated genotype-phenotype correlations and the missense variants in the affected individuals based on the structural modeling of rat VMAT2 encoded by Slc18a2, with cytoplasm- and lumen-facing conformations. A Caenorhabditis elegans model was created for functional studies.

RESULTS

A total of 19 homozygous SLC18A2 variants, including 3 recurrent variants, were identified using exome sequencing. The affected individuals typically showed global developmental delay, hypotonia, dystonia, oculogyric crisis, and autonomic nervous system involvement (temperature dysregulation/sweating, hypersalivation, and gastrointestinal dysmotility). Among the 58 affected individuals described to date, 16 (28%) died before the age of 13 years. Of the 17 patients with p.Pro237His, 9 died, whereas all 14 patients with p.Pro387Leu survived. Although a dopamine agonist mildly improved the disease symptoms in 18 of 21 patients (86%), some affected individuals with p.Ile43Phe and p.Pro387Leu showed milder phenotypes and presented prolonged survival even without treatment. The C. elegans model showed behavioral abnormalities.

CONCLUSION

These data expand the phenotypic and genotypic spectra of SLC18A2-related disorders.

Expanding SPTAN1 monoallelic variant associated disorders: From epileptic encephalopathy to pure spastic paraplegia and ataxia

PURPOSE

Nonerythrocytic αII-spectrin (SPTAN1) variants have been previously associated with intellectual disability and epilepsy. We conducted this study to delineate the phenotypic spectrum of SPTAN1 variants.

METHODS

We carried out SPTAN1 gene enrichment analysis in the rare disease component of the 100,000 Genomes Project and screened 100,000 Genomes Project, DECIPHER database, and GeneMatcher to identify individuals with SPTAN1 variants. Functional studies were performed on fibroblasts from 2 patients.

RESULTS

Statistically significant enrichment of rare (minor allele frequency < 1 × 10-5) probably damaging SPTAN1 variants was identified in families with hereditary ataxia (HA) or hereditary spastic paraplegia (HSP) (12/1142 cases vs 52/23,847 controls, p = 2.8 × 10-5). We identified 31 individuals carrying SPTAN1 heterozygous variants or deletions. A total of 10 patients presented with pure or complex HSP/HA. The remaining 21 patients had developmental delay and seizures. Irregular αII-spectrin aggregation was noted in fibroblasts derived from 2 patients with p.(Arg19Trp) and p.(Glu2207del) variants.

CONCLUSION

We found that SPTAN1 is a genetic cause of neurodevelopmental disorder, which we classified into 3 distinct subgroups. The first comprises developmental epileptic encephalopathy. The second group exhibits milder phenotypes of developmental delay with or without seizures. The final group accounts for patients with pure or complex HSP/HA.

Emergency Department Visits for Chronic Subdural Hematomas within 30 Days after Surgical Evacuation with and without Middle Meningeal Artery Embolization

BACKGROUND AND PURPOSE

Middle meningeal artery embolization after surgical evacuation of a chronic subdural hematomas is associated with fewer treatment failures than surgical evacuation. We compared emergency department visits within 30 days for patients with chronic subdural hematomas with and without adjunctive middle meningeal artery embolization.

MATERIALS AND METHODS

All cases of chronic subdural hematoma treated from January 1, 2018, through December 31, 2020, were retrospectively reviewed. Treatment was classified as surgery only or surgery combined with middle meningeal artery embolization. The primary outcome was 30-day emergency department presentation and readmission.

RESULTS

Of 137 patients who met the study criteria, 28 (20%) underwent surgery combined with middle meningeal artery embolization. Of these 28 patients, 15 (54%) underwent planned middle meningeal artery embolization and 13 (46%) underwent embolization after surgical failure. The mean chronic subdural hematoma size at presentation in the group with surgery only (n = 109, 20.5 [SD, 6.9] mm) was comparable with that in the combined group (n = 28, 18.7 [SD, 4.5] mm; P = .16). A significantly higher percentage of the surgery-only group presented to the emergency department within 30 days compared with the combined group (32 of 109 [29%] versus 2 of 28 [7%] patients; P = .02). No significant difference was found with respect to readmission (16 [15%] versus 1 [4%] patient; P = .11). Nine patients (8%) in the surgery-only group were readmitted for significant reaccumulation or residual subdural hematoma compared with only 1 patient (4%) in the combined group (P = .40).

CONCLUSIONS

Surgical evacuation combined with middle meningeal artery embolization in patients with chronic subdural hematoma is associated with fewer 30-day emergency department visits compared with surgery alone.

Biallelic ADAM22 pathogenic variants cause progressive encephalopathy and infantile-onset refractory epilepsy

Pathogenic variants in A Disintegrin And Metalloproteinase (ADAM) 22, the postsynaptic cell membrane receptor for the glycoprotein leucine-rich repeat glioma-inactivated protein 1 (LGI1), have been recently associated with recessive developmental and epileptic encephalopathy. However, so far, only two affected individuals have been described and many features of this disorder are unknown. We refine the phenotype and report 19 additional individuals harbouring compound heterozygous or homozygous inactivating ADAM22 variants, of whom 18 had clinical data available. Additionally, we provide follow-up data from two previously reported cases. All affected individuals exhibited infantile-onset, treatment-resistant epilepsy. Additional clinical features included moderate to profound global developmental delay/intellectual disability (20/20), hypotonia (12/20) and delayed motor development (19/20). Brain MRI findings included cerebral atrophy (13/20), supported by post-mortem histological examination in patient-derived brain tissue, cerebellar vermis atrophy (5/20), and callosal hypoplasia (4/20). Functional studies in transfected cell lines confirmed the deleteriousness of all identified variants and indicated at least three distinct pathological mechanisms: (i) defective cell membrane expression; (ii) impaired LGI1-binding; and/or (iii) impaired interaction with the postsynaptic density protein PSD-95. We reveal novel clinical and molecular hallmarks of ADAM22 deficiency and provide knowledge that might inform clinical management and early diagnostics.

Rare Treatable Cause of Demyelinating Leukoencephalopathy That One Cannot Afford to Miss

Biotinidase deficiency is a treatable neurometabolic disorder. It usually presents during the first year of life with seizures, ataxia, hypotonia, vision and hearing disturbance, alopecia, and skin rashes. It can have various neuroimaging findings but demyelinating leukoencephalopathy is an unusual finding in children with biotinidase deficiency that can cause diagnostic challenge as it can radiologically mimic perinatal hypoxic–ischemic encephalopathy or other leukodystrophies. It reverses with early diagnosis and treatment with biotin supplementation and the outcome is rewarding.

Compressive Myelopathy Secondary to TRPV4 Skeletal Dysplasia: Spondylometaphyseal Dysplasia, Kozlowski Type

Transient receptor potential vanilloid 4 channel (TRPV4) gene mutations have been described in skeletal system and peripheral nervous system pathology. The case described here is a 9-year-old male child patient, born to a nonconsanguineous marriage with normal birth history who had difficulty in walking and stiffness of joints for the last 7 years, and progressive weakness of all four limbs and urine incontinence for 1 year following falls. Physical examination showed below-average weight and height and short trunk. Musculoskeletal examination revealed bony prominence bilaterally in the knee joints and contractures in knee and elbow joints with brachydactyly; muscle tone was increased, with brisk deep tendon reflexes. Skeletal survey showed platyspondyly with anterior beaking with metaphyseal dysplasia. Magnetic resonance imaging of the spine revealed atlantoaxial instability with hyperintense signal changes at a cervicomedullary junction and upper cervical cord with thinning and spinal canal stenosis suggestive of compressive myelopathy with platyspondyly and anterior beaking of the spine at cervical, thoracic and lumbar vertebrae. Exome sequencing revealed a heterozygous de novo variant c.2389G > A in exon 15 of TRPV4, which results in the amino acid substitution p.Glu797Lys in the encoded protein. The characteristics observed indicated spondylometaphyseal dysplasia, Kozlowski type (SMD-K). The child underwent surgical intervention for compressive myelopathy by reduction of atlantoaxial dislocation with C1 lateral mass and C2 pars fusion using rib graft and fixation using screws and rods. To conclude, for any child presenting with progressive kyphoscoliosis, short stature, platyspondyly, and metaphyseal changes, a diagnosis of SMD-K should be considered and the patient and family should be advised to avoid spinal injuries.

Profile of Indian Children with Childhood Ataxia and Central Nervous System Hypomyelination/Vanishing White Matter Disease: A Single Center Experience from Southern India

Background  Childhood ataxia with central nervous system hypomyelination (CACH) is a recently described childhood inherited white matter disease, caused by mutations in any of the five genes encoding eukaryotic translation initiation factor ( eIF2B ). Methods  Retrospective review of the charts of children with CACH was performed from January 2014 to March 2020 at tertiary care center from Southern India. Diagnosis was based on magnetic resonance imaging (MRI) criteria or genetic testing. Results  Total number of children with CACH enrolled were 18. Male/female ratio was 10:8. Mean age of presentation was 37.11 months (range =  6-144 months). Affected siblings were seen in five (28%) cases. All children had spasticity, ataxia, and diffuse white matter changes with similar signal as cerebrospinal fluid on all pulse sequences on MRI brain. Of the 18 children, only nine are alive. Duration of illness among deceased children was 9.6667 months (range = 2-16 months). Waxing and waning of symptoms were seen in seven cases. Genetic analysis of EIF2B gene was performed in five cases, among which three mutations were novel. Conclusion  A diagnosis of childhood ataxia with central nervous system hypomyelination should be considered in patients presenting with acute onset neuroregression following infection or trauma with associated neuroimaging showing classical white matter findings.

Siblings with Glutaric Aciduria Type 1 with Atypical Phenotype with Novel Pathogenic Variant in GCDH Gene

Glutaric aciduria type 1 (GA1) is caused by a deficiency of the enzyme glutaryl CoA dehydrogenase. It generally presents with developmental delay, dystonia, and large head. We are reporting siblings of GA1, presenting with an atypical phenotype with novel pathogenic variant. Thirteen-year-old boy presented with global developmental delay and stiffness of limbs. Examination revealed normocephaly and generalized dystonia. MRI T2WI was suggestive of symmetrical posterior putaminal atrophy. Tandem mass spectroscopy (TMS) and urinary gas chromatography-mass spectrometry (GCMS) were normal. Genetic analysis revealed a novel pathogenic homozygous missense variant in GCDH gene. An 8-year-old girl younger sibling of above child also had developmental delay and dystonia, posterior putamen atrophy in the MRI of brain, and same pathogenic variant in GCDH gene. Parents screening showed heterozygous status in both parents of same pathogenic variant. Any child who presents with global developmental delay with dystonia even with normocephaly, isolated symmetrical posterior putamen changes, with normal TMS and GCMS, a possibility of glutaric aciduria type 1 has to be considered.

Cohort of Phenotype, Genotype, and Outcome of SCN Developmental and Epileptic Encephalopathies from Southern Part of India

The SCN encephalopathies are one of the rare early childhood intractable epileptic encephalopathies associated with pleomorphic seizures, cognitive decline, motor, and behavioral abnormalities that begin in early infancy. There is a dearth of data on phenotype and genotype of SCN encephalopathies from the Indian subcontinent, hence we are reporting clinical and molecular profile and outcome of SCN developmental and epileptic encephalopathies. This is a retrospective chart review of SCN developmental and epileptic encephalopathies in a tertiary care center, Bangalore, India between January 2015 and March 2020. All children with clinical features of SCN developmental and epileptic encephalopathies and confirmed with pathogenic variants were included. A total of 50 cases of SCN developmental and epileptic encephalopathies were analyzed, 31 of them were male and the mean age of presentation was 7.8 months. Precipitating factors for the first episode of seizure were fever and vaccination accounting for 33 and 8 children, respectively. Forty (80%) children had prolonged seizures and 15 (30%) had epileptic spasms. All children had a normal birth history and normal development before the onset of seizures, which was followed by developmental delay and regression. Thirty (60%) children had behavioral difficulties, notable hyperactivity, and autistic features. Neuroimaging and the initial electroencephalogram (EEG) were normal in all patients. The mean age of abnormal EEG was 14 months. The various subtypes of SCN variants were SCN1A in 31 children followed by SCN2A and SCN9A in eight children each and SCN1B in three children. Frameshift and nonsense mutations were associated with more severe phenotype and poor outcome compared with missense mutations. Thirty-four patients partially responded to treatment and the rest were refractory. The results of genetic testing were used to guide treatment; sodium channel blocking antiepileptic drugs were discontinued in 15 patients and sodium channel blocking agents were started in 3 patients with partial response. Three out of four children on stiripentol had a partial response. The SCN developmental and epileptic encephalopathies can present with epileptic spasms in addition to other types of seizures. Epileptic spasms are more common in nonsense and frameshift mutations. The outcome is poor in children with epileptic spasms compared with those without epileptic spasms. Genetic testing helps to select antiepileptic drugs that lead to seizure reduction.

Novel ALDH3A2 mutations in structural and functional domains of FALDH causing diverse clinical phenotypes in Sjögren-Larsson syndrome patients

Mutations in ALDH3A2 cause Sjögren-Larsson syndrome (SLS), a neuro-ichthyotic condition due to the deficiency of fatty aldehyde dehydrogenase (FALDH). We screened for novel mutations causing SLS among Indian ethnicity, characterized the identified mutations in silico and in vitro, and retrospectively evaluated their role in phenotypic heterogeneity. Interestingly, asymmetric distribution of nonclassical traits was observed in our cases. Nerve conduction studies suggested intrinsic-minus-claw hands in two siblings, a novel neurological phenotype to SLS. Genetic testing revealed five novel homozygous ALDH3A2 mutations in six cases: Case-1-NM_000382.2:c.50C>A, NP_000373.1:p.(Ser17Ter); Case-2-NM_000382.2:c.199G>T, NP_000373.1:p.(Glu67Ter); Case-3-NM_000382.2:c.1208G>A, NP_000373.1:p.(Gly403Asp); Case-4-NM_000382.2:c.1325C>T, NP_000373.1:p.(Pro442Leu); Case-5 and -6 NM_000382.2:c.1349G>A, NP_000373.1:p.(Trp450Ter). The mutations identified were predicted to be pathogenic and disrupt the functional domains of the FALDH. p.(Pro442Leu) at the C-terminal α-helix, might impair the substrate gating process. Mammalian expression studies with exon-9 mutants confirmed the profound reduction in the enzyme activity. Diminished aldehyde-oxidizing activity was observed with cases-2 and 3. Cases-2 and 3 showed epidermal hyperplasia with mild intracellular edema, spongiosis, hypergranulosis, and perivascular-interstitial lymphocytic infiltrate and a leaky eosinophilic epidermis. The presence of keratin-containing milia-like lipid vacuoles implies defective lamellar secretion with p.(Gly403Asp). This study improves our understanding of the clinical and mutational diversity in SLS, which might help to fast-track diagnostic and therapeutic interventions of this debilitating disorder.