Evaluation of the Patients with the Diagnosis of Pontocerebellar Hypoplasia: A Multicenter National Study.

Pontocerebellar hypoplasia (PCH) is a heterogeneous group of neurodegenerative disorders characterized by hypoplasia and degeneration of the cerebellum and pons. We aimed to identify the clinical, laboratory, and imaging findings of the patients with diagnosed PCH with confirmed genetic analysis. We collected available clinical data, laboratory, and imaging findings in our retrospective multicenter national study of 64 patients with PCH in Turkey. The genetic analysis included the whole-exome sequencing (WES), targeted next-generation sequencing (NGS), or single gene analysis. Sixty-four patients with PCH were 28 female (43.8%) and 36 (56.3%) male. The patients revealed homozygous mutation in 89.1%, consanguinity in 79.7%, pregnancy at term in 85.2%, microcephaly in 91.3%, psychomotor retardation in 98.4%, abnormal neurological findings in 100%, seizure in 63.8%, normal biochemistry and metabolic investigations in 92.2%, and dysmorphic findings in 51.2%. The missense mutation was found to be the most common variant type in all patients with PCH. It was detected as CLP1 (n = 17) was the most common PCH related gene. The homozygous missense variant c.419G > A (p.Arg140His) was identified in all patients with CLP1. Moreover, all patients showed the same homozygous missense variant c.919G > T (p.A307S) in TSEN54 group (n = 6). In Turkey, CLP1 was identified as the most common causative gene with the identical variant c.419G > A; p.Arg140His. The current study supports that genotype data on PCH leads to phenotypic variability over a wide phenotypic spectrum.

Biallelic NAA60 variants with impaired n-terminal acetylation capacity cause autosomal recessive primary familial brain calcifications.

Primary familial brain calcification (PFBC) is characterized by calcium deposition in the brain, causing progressive movement disorders, psychiatric symptoms, and cognitive decline. PFBC is a heterogeneous disorder currently linked to variants in six different genes, but most patients remain genetically undiagnosed. Here, we identify biallelic NAA60 variants in ten individuals from seven families with autosomal recessive PFBC. The NAA60 variants lead to loss-of-function with lack of protein N-terminal (Nt)-acetylation activity. We show that the phosphate importer SLC20A2 is a substrate of NAA60 in vitro. In cells, loss of NAA60 caused reduced surface levels of SLC20A2 and a reduction in extracellular phosphate uptake. This study establishes NAA60 as a causal gene for PFBC, provides a possible biochemical explanation of its disease-causing mechanisms and underscores NAA60-mediated Nt-acetylation of transmembrane proteins as a fundamental process for healthy neurobiological functioning.

Optic neuritis in Turkish children and adolescents: A multicenter retrospective study.

BACKGROUND: Various etiologies may underlie optic neuritis, including autoantibody-mediated disorders described in the last decade. We re-examined demographic, clinical, laboratory features and prognostic factors in pediatric patients with autoimmune optic neuritis according to current knowledge. METHODS: Cases of pediatric ON from 27 centers in Türkiye diagnosed between 2009 and 2022 were included for retrospective evaluation. RESULTS: The study included 279 patients, 174 females and 105 males, with a female-to-male ratio of 1.65. The average age at onset was 12.8 ± 3.4 years, and mean follow-up, 2.1 years (range: 1-12.1 years). Patients <10 years old were grouped as "prepubertal" and those ≥10 years old as "others". The diagnoses made at the end of follow-up were multiple sclerosis associated optic neuritis (n = 90, 32.3 %), single isolated optic neuritis (n = 86, 31 %), clinically isolated syndrome (n = 41, 14.7 %), myelin oligodendrocyte glycoprotein antibody associated optic neuritis (n = 22, 7.9 %), and relapsing isolated optic neuritis (n = 18, 6.5 %). Predominant diagnoses were myelin oligodendrocyte glycoprotein antibody associated optic neuritis and acute disseminated encephalomyelitis associated optic neuritis in the prepubertal group and multiple sclerosis associated optic neuritis in the older group. Recurrences were observed in 67 (24 %) patients, including 28 with multiple sclerosis associated optic neuritis, 18 with relapsing isolated optic neuritis, 11 with myelin oligodendrocyte glycoprotein antibody associated optic neuritis, 8 with aquaporin-4 antibody related optic neuritis, and 2 with chronic relapsing inflammatory optic neuropathy. Recurrences were more common among female patients. Findings supporting the diagnosis of multiple sclerosis included age of onset ≥ 10 years (OR=1.24, p = 0.027), the presence of cranial MRI lesions (OR=26.92, p<0.001), and oligoclonal bands (OR=9.7, p = 0.001). Treatment in the acute phase consisted of intravenous pulse methylprednisolone (n = 46, 16.5 %), pulse methylprednisolone with an oral taper (n = 212, 76 %), and combinations of pulse methylprednisolone, plasmapheresis, or intravenous immunoglobulin (n = 21, 7.5 %). Outcome at 12 months was satisfactory, with 247 out of 279 patients (88.5 %) demonstrating complete recovery. Thirty-two patients exhibited incomplete recovery and further combination treatments were applied. Specifically, patients with relapsing isolated optic neuritis and aquaporin-4 antibody related optic neuritis displayed a less favorable prognosis. CONCLUSION: Our results suggest optic neuritis is frequently bilateral in prepubertal and unilateral in peri­ or postpubertal patients. Age of onset 10 or older, presence of oligoclonal bands, and brain MRI findings reliably predict the development of multiple sclerosis. The risk of developing multiple sclerosis increases mostly during the second and third years of follow-up. Relapsing isolated optic neuritis remains a separate group where the pathogenesis and outcome remain unclear. Investigation of predisposing and diagnostic biomarkers and long follow-up could help to define this group.

Retracted: Clinical and genetic evaluations of rare childhood epilepsies in Turkey's national cohort.

Aycan Ünalp, Yigithan Güzin, Bülent Ünay, Ayse Tosun, Dilek Çavusoglu, Hande Gazeteci Tekin, Semra Hiz Kurul, Ebru Arhan, Selvinaz Edizer, Gülten Öztürk, Uluç Yis, Ünsal Yilmaz, Turkish Rare Epilepsies Study Group, Clinical and genetic evaluations of rare childhood epilepsies in Turkey's national cohort, Epileptic Disorders, 2023, (https://doi.org/10.1002/epd2.20150) The above article, published online on 16 August 2023 on Wiley Online Library (www.onlinelibrary.wiley.com), has been retracted by agreement between the authors, the Editor-in-Chief, Sándor Beniczky, and John Wiley & Sons Ltd. The authors asked for a retraction based on an experimental error which would alter the results of the study if corrected.

Evaluation of risk factors for recurrence of cutaneous adverse reactions due to anti-seizure medications in children: A retrospective study.

Background: Cutaneous adverse reactions (CARs) are one of the most important reasons for anti-seizure medication (ASM) discontinuation in epilepsy. However, such discontinuations can cause an increase in seizures. This study investigates the risk factors for ASM-related rash recurrence in children. Methods: This retrospective case-control study consisted of the patient group with a single rash due to ASMs (group 1), the patient group with rash recurrence (group 2), and the control group. While the demographic and clinical features of group 1 and the control group were compared in terms of a single rash, group 1 and group 2 were compared for rash recurrence. Results: Group 1, group 2, and control group consisted of 112, 33, and 166 patients, respectively. Female gender was a risk factor for a single rash (P < 0.001) but not for recurrence (P = 0.439). Presence of atopic disease [odds ratio (OR): 9.5, 95% confidence interval (CI): 3.8-23.1, P < 0.001], family history of drug allergy (OR: 26.3, 95% CI: 9.6-72.1, P < 0.001), and polytherapy (OR: 23.5, 95% CI: 8.7-62.9, P < 0.001) were risk factors for rash recurrence. Aromatic nature of both the ASMs associated with the first rash (OR: 14.4, 95% CI: 3.2-63.2, P < 0.001) and rash recurrence (OR: 11.3, 95% CI: 4.6-27.5, P < 0.001) were determined as risk factors separately. Conclusion: Careful use of aromatic drugs may prevent recurrence of ASM-related CAR in children, particularly in cases of personal history of allergic disease and family history of drug allergy.

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.

Novel biallelic variants affecting the OTU domain of the gene OTUD6B associate with severe intellectual disability syndrome and molecular dynamics simulations.

Intellectual developmental disorder with dysmorphic facies, seizures, and distal limb anomalies (IDDFSDA) is an autosomal recessive multisystem disorder caused by compound heterozygous or homozygous variants in the gene OTUD6B. Herein, we describe novel pathogenic compound heterozygous variants in OTUD6B identified via whole-exome sequencing in an index case exhibited the severe IDDFSDA phenotype. The potential pathogenicity of the novel frameshift and missense variants in the index case was investigated using in silico tools. The truncating frameshift variant in one allele was predicted to undergo degradation via nonsense-mediated decay of the mRNA molecule. To predict the severity of the damage to the protein caused by the missense variant in the other allele and its effects on phenotypic severity was further investigated together with a previously reported first homozygous missense variant in the same domain in another patient with a less severe IDDFSDA phenotype using structural modeling and molecular dynamics (MD) simulations for the first time. Based on these analyzes, it is anticipated that Tyr216Cys in the earlier reported case with less severe IDDFSDA will lead to localized destabilization, whereas Ile274Arg in the presented index case with the severe IDDFSDA phenotype will lead to significant distortion in the overall fold of OTUD6B. Our findings suggest that compound LOF and ultrarare missense variants may be contribute to the underlying variability expressivity associated with this disorder. In conclusion, our findings support that the clinical severity could be related with the predicted functional severity of the variations in OTUD6B. However, additional functional studies are required.

Rotavirus encephalopathy with concomitant acute cerebellitis: report of a case and review of the literature.

Rotavirus is a leading cause of gastroenteritis in children under 5 years of age. It is known that neurological manifestations like seizures, encephalopathy and encephalitis can rarely be seen due to rotavirus infections. Cerebellar involvement is extremely rare. We present an uncommon neurological manifestation of rotavirus infection in a 4-year-old Turkish child who presented with hypotonia, reduced consciousness and mutism. Magnetic resonance imaging revealed diffusion abnormalities in the splenium of corpus callosum and nucleus dentatus bilaterally. She was diagnosed with rotavirus cerebellitis. She improved well with dexamethasone and intravenous immunoglobulin but still has dysarthria and poor fine motor coordination.

Clinico-Genetic, Imaging and Molecular Delineation of COQ8A-Ataxia: A Multicenter Study of 59 Patients.

OBJECTIVE: To foster trial-readiness of coenzyme Q8A (COQ8A)-ataxia, we map the clinicogenetic, molecular, and neuroimaging spectrum of COQ8A-ataxia in a large worldwide cohort, and provide first progression data, including treatment response to coenzyme Q10 (CoQ10). METHODS: Cross-modal analysis of a multicenter cohort of 59 COQ8A patients, including genotype-phenotype correlations, 3D-protein modeling, in vitro mutation analyses, magnetic resonance imaging (MRI) markers, disease progression, and CoQ10 response data. RESULTS: Fifty-nine patients (39 novel) with 44 pathogenic COQ8A variants (18 novel) were identified. Missense variants demonstrated a pleiotropic range of detrimental effects upon protein modeling and in vitro analysis of purified variants. COQ8A-ataxia presented as variable multisystemic, early-onset cerebellar ataxia, with complicating features ranging from epilepsy (32%) and cognitive impairment (49%) to exercise intolerance (25%) and hyperkinetic movement disorders (41%), including dystonia and myoclonus as presenting symptoms. Multisystemic involvement was more prevalent in missense than biallelic loss-of-function variants (82-93% vs 53%; p = 0.029). Cerebellar atrophy was universal on MRI (100%), with cerebral atrophy or dentate and pontine T2 hyperintensities observed in 28%. Cross-sectional (n = 34) and longitudinal (n = 7) assessments consistently indicated mild-to-moderate progression of ataxia (SARA: 0.45/year). CoQ10 treatment led to improvement by clinical report in 14 of 30 patients, and by quantitative longitudinal assessments in 8 of 11 patients (SARA: -0.81/year). Explorative sample size calculations indicate that ≥48 patients per arm may suffice to demonstrate efficacy for interventions that reduce progression by 50%. INTERPRETATION: This study provides a deeper understanding of the disease, and paves the way toward large-scale natural history studies and treatment trials in COQ8A-ataxia. ANN NEUROL 2020;88:251-263.

Electrophysiological Subtypes and Prognostic Factors of Childhood Guillain-Barré Syndrome.

INTRODUCTION: We assessed the clinical, epidemiologic, electrophysiological and prognostic characteristics of childhood Guillain-Barré Syndrome admitted to 13 pediatric neurology centers in Turkey. METHOD: Using a standard data recording form age, sex, duration of symptoms, distribution of weakness at onset, cranial nerve involvement, cerebrospinal fluid findings, electrophysiological findings, duration of hospitalization, requirement of ventilation, treatment and clinical evaluation scale at onset, discharge and 1, 3, 6, and 12 months after discharge were recorded. RESULTS: Among the 236 children with a median age of 6.8 years there was a male to female ratio of 1.3. Based on the electrophysiological features; 84 patients were classified as acute inflammatory demyelinating polyrediculoneuropathy (AIDP), 61 as acute motor axonal neuropathy (AMAN), 21 as acute motor-sensory axonal neuropathy (AMSAN). The incidence of cranial nerve involvement was 16%, and was related to lower clinical scores at discharge and 6 months after discharge. Clinical scale scores between axonal and demyelinating subgroups did not show statistically significant difference except for admission (p<0.05). CONCLUSION: Electrophysiological subtypes are not important in prognosis in our series. However, duration of weakness, duration of hospitalization and ventilation requirement can affect prognosis negatively.

Genetic Landscape of Congenital Myasthenic Syndromes From Turkey: Novel Mutations and Clinical Insights.

Congenital myasthenic syndromes are clinically and genetically heterogeneous disorders of neuromuscular transmission. Most are treatable, but certain subtypes worsen with cholinesterase inhibitors. This underlines the importance of genetic diagnosis. Here, the authors report on cases with genetically proven congenital myasthenic syndromes from Turkey. The authors retrospectively reviewed their experience of all patients with congenital myasthenic syndromes, referred over a 5-year period (2011-2016) to the Child Neurology Department of Dokuz Eylül University, Izmir, Turkey. In addition, PubMed was searched for published cases of genetically proven congenital myasthenic syndromes originating from Turkey. In total, the authors identified 43 (8 new patients, 35 recently published patients) cases. Defects in the acetylcholine receptor (n = 15; 35%) were the most common type, followed by synaptic basal-lamina associated (n = 14; 33%) and presynaptic syndromes (n = 10; 23%). The authors had only 3 cases (7%) who had defects in endplate development. One patient had mutation GFPT1 gene (n = 1; 2%). Knowledge on congenital myasthenic syndromes and related genes in Turkey will lead to prompt diagnosis and treatment of these rare neuromuscular disorders.

Schwartz-Jampel syndrome with gastroduodenal bleeding.

Schwartz-Jampel syndrome is a rare autosomal recessive disorder with joint contractures, generalized myotonia, skeletal anomalies, and facial dysmorphism. The patients with Schwartz-Jampel syndrome have muscle stiffness and electromyography reveals complex, repetitive discharges as myotonic discharges. It is unusual for a Schwartz-Jampel syndrome case to have recurrent gastrointestinal bleeding episodes. The stable endothelial barrier is provided by perlecan which is an important component of vascular structures. Thus, perlecan deficiency may cause recurrent gastroduodenal bleeding. Our report is unique with being the first reported Schwartz-Jampel syndrome case with gastrointestinal bleeding.

Myelin Oligodendrocyte Glycoprotein Antibody Persistency in a Steroid-Dependent ADEM Case.

Myelin oligodendrocyte glycoprotein (MOG) is a candidate target antigen in demyelinating central nervous system diseases, including acute disseminated encephalomyelitis (ADEM), neuromyelitis optica, and multiple sclerosis. It may give prognostic information regarding monophasic or recurrent course of the disease. MOG antibodies have been shown to be positive in high titers during the first episode of ADEM with rapidly decreasing to undetectable limits after recovery. However, persistent MOG antibodies are considered as a predicting factor for multiple sclerosis, optic neuritis relapses, and incomplete recovery of ADEM. Here we report a unique case with persistent MOG antibodies presented with multiphasic ADEM-like attacks. A 6-year-old girl was consulted with encephalopathy, gait disturbance, and oculomotor nerve palsy. Periventricular white matter lesions were seen on cranial magnetic resonance imaging studies. ADEM was diagnosed and treated with steroid. During follow-up, she experienced repeated episodes after steroid therapy termination. We were able to search MOG antibody at the ninth attack. The positivity of this antibody remained. It was thought to be associated with steroid-dependent course, and azathioprine and intravenous human immunoglobulin treatment were added. Patients with persistent MOG antibodies may benefit from addition of immunosuppressant agents, which may decrease the number of attacks.

Posterior reversible leukoencephalopathy syndrome with spinal cord involvement in a 9-year-old girl.

We report the youngest pediatric case of posterior reversible leukoencephalopathy syndrome confined to brainstem and spinal cord. At presentation bicytopenia, renal derangement, visual disturbances, magnetic resonance imaging findings, increased protein content, IgG index and cell count in the cerebrospinal fluid led us to extensive search for myelitis. She received a short course of steroid treatment. The final diagnosis was hypertension due to reflux nephropathy. Severe hypertension that exceeds the range of autoregulation in anterior spinal territory may result in spinal posterior reversible leukoencephalopathy syndrome. Clinicians should be aware of spinal posterior reversible leukoencephalopathy syndrome when cases have extensive lesions in the brainstem and spinal cord with none or minimal clinical findings, so called "clinical radiologic dissociation".

A novel mutation in the mitochondrial DNA cytochrome b gene (MTCYB) in a patient with Prader Willi syndrome.

In recent years, it has been suggested that defects in energy metabolism may accompany Prader Willi syndrome. Mutations in the mitochondrial cytochrome b gene have been commonly associated isolated mitochondrial myopathy and exercise intolerance, rarely with multisystem disorders. The authors describe a novel mutation (mt. 15209T>C) in mitochondrial cytochrome b gene in a 2-year-old girl with Prader-Willi syndrome with a clinical history of lactic acidosis attacks, renal sodium loss, hepatopathy, progressive cerebral atrophy, and sudden death. The authors suggest that atypical clinical findings in patients with Prader-Willi syndrome should direct the physician to search for a mitochondrial disease.

Expression patterns of micro-RNAs 146a, 181a, and 155 in subacute sclerosing panencephalitis.

Subacute sclerosing panencephalitis is caused by persistent brain infection of mutated virus, showing inflammation, neurodegeneration, and demyelination. Although many factors are emphasized in the pathogenesis of subacute sclerosing panencephalitis, the exact mechanism of neurodegeneration remains unknown. Micro-RNAs are small, noncoding RNAs that regulate gene expression at the posttranscriptional levels. Micro-RNAs are essential for normal immune system development; besides they are also implicated in the pathogenesis of many chronic inflammatory disorders. The aim of this study is to investigate the expression patterns of micro-RNAs 146a, 181a, and 155 in peripheral blood mononuclear cells of patients with subacute sclerosing panencephalitis. We enrolled 39 patients with subacute sclerosing panencephalitis and 41 healthy controls. Quantitative analysis of micro-RNAs 146a, 181a, and 155 were performed using specific stem-loop primers followed by real-time polymerase chain reaction. All of 3 micro-RNAs were upregulated in subacute sclerosing panencephalitis patients. In addition, the level of micro-RNA 155 expression was higher in stage 3 patients. But, micro-RNA 146a and 181a expression levels showed no association or correlation with clinically relevant data. Alteration of peripheral blood mononuclear cell micro-RNAs in subacute sclerosing panencephalitis may shed new light on the pathogenesis of disease and may contribute to the aberrant systemic rise in mRNA levels in subacute sclerosing panencephalitis.