Distinct neurological phenotypes associated with biallelic loss of NOTCH3 function: evidence for recessive inheritance.

BACKGROUND: NOTCH3 variants are known to be linked to cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL). However, some null NOTCH3 variants with homozygous inheritance cause neurological symptoms distinct from CADASIL. The aim of this study was to expand the clinical spectrum of this distinct condition and provide further evidence of its autosomal recessive inheritance. METHODS AND RESULTS: Whole exome sequencing (WES) was performed on a proband who exhibited livedo racemosa, ataxia, cognitive decline, seizures, and MRI white matter abnormalities without anterior temporal pole lesions. Segregation analysis was conducted with Sanger sequencing. WES of the proband identified a novel homozygous NOTCH3 null variant (c.2984delC). The consanguineous parents were confirmed as heterozygous variant carriers. In addition, three heterozygous NOTCH3 null variants were reported as incidental findings in three unrelated cases analyzed in our center. CONCLUSION: The findings of this study suggest an autosomal recessive inheritance pattern in this early-onset leukoencephalopathy, in contrast to CADASIL's dominant gain-of-function mechanism; which is a clear example of genotype-phenotype correlation. Comprehensive genetic analysis provides valuable insights into disease mechanisms and facilitates diagnosis and family planning for NOTCH3-associated neurological disorders.

A comparative study on prophylactic efficacy of cinnarizine and amitriptyline in childhood migraine: a randomized double-blind clinical trial.

BACKGROUND: Pediatric migraine prophylaxis is indicated when headaches are frequent and/or disabling. We aimed to conduct a study to compare the efficacy of cinnarizine and amitriptyline in pediatric migraine prophylaxis. METHODS: In a randomized, double-blind trial, patients aged 4-17 years with migraine who were eligible for prophylaxis enrolled. The primary outcome was a reduction response rate of ≥50% with p < 0.005 with respect to headache characteristics. The secondary outcome was migraine disability assessment. We evaluated patients every four weeks for three months: T1: week 4, T2: week 8 and T3: week 12. The safety profile was also assessed. RESULTS: Thirty patients were randomly assigned to each group. However, 43 patients completed the trial. Headache frequency decreased in amitriptyline group more effectively in T1 (p = 0.004). Amitriptyline was more successful in reducing the headache duration in all three periods (p < 0.005). There was no significant difference in severity improvement and reducing disability score between the two groups (p > 0.005). No serious adverse events were observed. CONCLUSIONS: Both medications are effective in ameliorating migraine headaches and related disabilities. However, amitriptyline appears be a preferable option over cinnarizine, given its faster onset of action, efficacy in reducing headache duration and longer-lasting effects.Trial Registration: The study was registered with the Iranian Registry of Clinical Trials (IRCT) under the code IRCT-20191112045413N1.

The genetic basis of early-onset hereditary ataxia in Iran: results of a national registry of a heterogeneous population.

BACKGROUND: To investigate the genetics of early-onset progressive cerebellar ataxia in Iran, we conducted a study at the Children's Medical Center (CMC), the primary referral center for pediatric disorders in the country, over a three-year period from 2019 to 2022. In this report, we provide the initial findings from the national registry. METHODS: We selected all early-onset patients with an autosomal recessive mode of inheritance to assess their phenotype, paraclinical tests, and genotypes. The clinical data encompassed clinical features, the Scale for the Assessment and Rating of Ataxia (SARA) scores, Magnetic Resonance Imaging (MRI) results, Electrodiagnostic exams (EDX), and biomarker features. Our genetic investigations included single-gene testing, Whole Exome Sequencing (WES), and Whole Genome Sequencing (WGS). RESULTS: Our study enrolled 162 patients from various geographic regions of our country. Among our subpopulations, we identified known and novel pathogenic variants in 42 genes in 97 families. The overall genetic diagnostic rate was 59.9%. Notably, we observed PLA2G6, ATM, SACS, and SCA variants in 19, 14, 12, and 10 families, respectively. Remarkably, more than 59% of the cases were attributed to pathogenic variants in these genes. CONCLUSIONS: Iran, being at the crossroad of the Middle East, exhibits a highly diverse genetic etiology for autosomal recessive hereditary ataxia. In light of this heterogeneity, the development of preventive strategies and targeted molecular therapeutics becomes crucial. A national guideline for the diagnosis and management of patients with these conditions could significantly aid in advancing healthcare approaches and improving patient outcomes.

TPP1 Variants in Iranian patients: A Novel Pathogenic Homozygous Variant Causing Neuronal Ceroid Lipofuscinosis 2.

Introduction: TPP1 variants have been identified as a causative agent of neuronal ceroid lipofuscinosis 2 disease, that ataxia is one of its clinical features. Therefore, here, molecular study of TPP1 variants is presented in an Iranian cohort and a novel pathogenic variant is described. Methods: This investigation was conducted as a cross-sectional study in a tertiary referral hospital, Children's Medical Center, Pediatrics Center of Excellence. Clinical presentations and pedigrees were documented. Patients with cerebellar ataxia were enrolled in this study. Next-generation sequencing was applied to confirm the diagnosis. Segregation and bioinformatics analyses were also done for the variants using Sanger sequencing. Results: Forty-five patients were included in our study. The mean age of onset was 104 (+55.60) months (minimum = 31 months, maximum = 216 months). The majority of cases (73.3%) were born to consanguineous parents and only 1 patient (2.2%) had an affected sibling. Of the 45 patients, only 1 patient with a novel pathogenic variant (c.1425_1425+1delinsAT, p.A476Cfs*15) in the TPP1 gene was identified. Discussion: The main strength of current study is the relatively large sample size. Besides, a novel pathogenic variant could be important toward the diagnosis and management of this condition. With significant advances in various therapies, early diagnosis could improve the treatments using personalized-based medicine.

Clinical application of next generation sequencing for Mendelian disease diagnosis in the Iranian population.

Next-generation sequencing (NGS) has been proven to be one of the most powerful diagnostic tools for rare Mendelian disorders. Several studies on the clinical application of NGS in unselected cohorts of Middle Eastern patients have reported a high diagnostic yield of up to 48%, correlated with a high level of consanguinity in these populations. We evaluated the diagnostic utility of NGS-based testing across different clinical indications in 1436 patients from Iran, representing the first study of its kind in this highly consanguineous population. A total of 1075 exome sequencing and 361 targeted gene panel sequencing were performed over 8 years at a single clinical genetics laboratory, with the majority of cases tested as proband-only (91.6%). The overall diagnostic rate was 46.7%, ranging from 24% in patients with an abnormality of prenatal development to over 67% in patients with an abnormality of the skin. We identified 660 pathogenic or likely pathogenic variants, including 241 novel variants, associated with over 342 known genetic conditions. The highly consanguineous nature of this cohort led to the diagnosis of autosomal recessive disorders in the majority of patients (79.1%) and allowed us to determine the shared carrier status of couples for suspected recessive phenotypes in their deceased child(ren) when direct testing was not possible. We also highlight the observations of recessive inheritance of genes previously associated only with dominant disorders and provide an expanded genotype-phenotype spectrum for multiple less-characterized genes. We present the largest mutational spectrum of known Mendelian disease, including possible founder variants, throughout the Iranian population, which can serve as a unique resource for clinical genomic studies locally and beyond.

Persistent basal ganglia involvement in aminoacylase-1 deficiency: expanding imaging findings and review of literature.

BACKGROUND: Aminoacylase-1 deficiency (ACY1D) is an autosomal recessive rare inborn error of metabolism, which is caused by disease-causing variants in the ACY1. This disorder is characterized by increased urinary excretion of specific N-acetyl amino acids. Affected individuals demonstrate heterogeneous clinical manifestations which are primarily neurologic problems. In neuroimaging, corpus callosum hypoplasia, cerebellar vermis atrophy, and delayed myelination of cerebral white matter have been reported. AIMS: Finding disease-causing variant and expanding imaging findings in a patient with persistent basal ganglia involvement. METHODS: Whole-exome sequencing was performed in order to identify disease-causing variants in an affected 5-year-old male patient who presented with neurologic regression superimposed on neurodevelopmental delay following a febrile illness. He had inability to walk, cognitive impairment, speech delay, febrile-induced seizures, truncal hypotonia, moderate to severe generalized dystonia, and recurrent metabolic decompensation. RESULTS: All metabolic tests were normal except for a moderate metabolic acidosis following febrile illnesses. The results of serial brain magnetic resonance imaging (MRI) at ages 1 and 4.5 years revealed persistent bilateral and symmetric abnormal signals in basal ganglia mainly caudate and globus pallidus nuclei with progression over time in addition to a mild supratentorial atrophy. A homozygous missense variant [NM_000666.3: c.1057C>T; p.(Arg353Cys)] was identified in the ACY1, consistent with aminoacylase-1 deficiency. Variant confirmation in patient and segregation analysis in his family were performed using Sanger sequencing. CONCLUSIONS: Our findings expanded the phenotype spectrum of ACY1-related neurodegeneration by demonstrating persistent basal ganglia involvement and moderate to severe generalized dystonia.

A comprehensive study of mutation and phenotypic heterogeneity of childhood mitochondrial leukodystrophies.

OBJECTIVE: Mitochondrial leukodystrophies (MLs) are mainly caused by impairments of the mitochondrial respiratory chains. This study reports the mutation and phenotypic spectrum of a cohort of 41 pediatric patients from 39 distinct families with MLs among 320 patients with a molecular diagnosis of leukodystrophies. METHODS: This study summarizes the clinical, imaging, and molecular data of these patients for five years. RESULTS: The three most common symptoms were neurologic regression (58.5%), pyramidal signs (58.5%), and extrapyramidal signs (43.9%). Because nuclear DNA mutations are responsible for a high percentage of pediatric MLs, whole exome sequencing was performed on all patients. In total, 39 homozygous variants were detected. Additionally, two previously reported mtDNA variants were identified with different levels of heteroplasmy in two patients. Among 41 mutant alleles, 33 (80.4%) were missense, 4 (9.8%) were frameshift (including 3 deletions and one duplication), and 4 (9.8%) were splicing mutations. Oxidative phosphorylation in 27 cases (65.8%) and mtDNA maintenance pathways in 8 patients (19.5%) were the most commonly affected mitochondrial pathways. In total, 5 novel variants in PDSS1, NDUFB9, FXBL4, SURF1, and NDUSF1 were also detected. In silico analyses showed how each novel variant may contribute to ML pathogenesis. CONCLUSIONS: The findings of this study suggest whole-exome sequencing as a strong diagnostic genetic tool to identify the causative variants in pediatric MLs. In comparison between oxidative phosphorylation (OXPHOS) and mtDNA maintenance groups, brain stem and periaqueductal gray matter (PAGM) involvement were more commonly seen in OXPHOS group (P value of 0.002 and 0.009, respectively), and thinning of corpus callosum was observed more frequently in mtDNA maintenance group (P value of 0.042).

Evaluation of the Effectiveness of Risperidone in Treating Breath-Holding Spells in Children.

Objectives: Breath holding spells (BHS) are a type of syncope in children that is commonly seen in the first years of life. Although these attacks do not cause serious damage to the child's brain, in severe or repeated cases, they expose the brain to hypoxia and cause a lot of stress in parents. In these cases, the clinician should consider therapy. The purpose of this study is to investigate the effectiveness of Risperidone in the treatment of BHS in children visiting the neurology clinic of the Children's Medical Center Hospital. Materials & Methods: In this randomized clinical trial, the statistical population included patients with the history of Breath Holding spells grades 2 to 3 (after ruling out of seizure disorders) over one year old, visiting the neurology clinic of Tehran Children's Medical Center in 2019. The subjects were randomly selected from patients visiting the clinic using a table of random numbers from the admit ion list. After providing the necessary explanations and obtaining informed consent from their parents, they were treated with low-dose Risperidone (maximum 1 mg) for three months. The patients were observed for three months in terms of frequency and severity of spells monthly. Results: In this study, the median (25th and 75th percentile) age of subjects was 2.3 (2.0-2.6) years. Both the number and severity of seizures in the subjects had a statistically significant decrease in the period after treatment with Risperidone (P<0.001). The studied boys and girls experienced statistically significant decrease in terms of both the frequency of spells (P-value of 0.002 and 0.039) and intensity of seizures (P=0.016) and P=0.008), respectively after treatment with Risperidone. Also, in the studied children under 2 years old and over 2 years old, both the frequency (P=0.021 and P=0.004) and intensity of spells (P=0.008) 0.016 for subjects under and over 2 years, respectively) had a statistically significant decrease after treatment with risperidone compared to pretreatment. Conclusion: According to the results of this study, it seems that both the frequency and the intensity of spells in children (regardless of gender and age group), experienced a statistically significant decrease after treatment with Risperidone. We suggest conducting a more comprehensive study considering a larger sample size in order to estimate this issue more correctly.

A Comparative Study of EEG and aEEG in Seizure Diagnosis in Infants Admitted to the NICU.

Objectives: Seizure is a common sign in neonates hospitalized in the neonatal intensive care units (NICU) that may lead to morbidity and mortality. Most neonatal seizures are subclinical. Conventional EEG (cEEG) is the gold standard for detecting and monitoring seizures but is not widely available. Amplitude-integrated electroencephalography (aEEG) has been used for over a decade to evaluate infants with seizures. In this study, we tried to determine the efficacy of aEEG as a widely available diagnostic tool in diagnosing seizures. Materials & Methods: All cases with seizures or suspicious seizures were admitted to the NICU of the Children's Medical Center for one year. cEEG and aEEG were performed for these infants. aEEG was recorded for at least six hours with a description of the tracing. Clinical information, outcomes, and questionnaires (patient information) were recorded in detail. The obtained data were analyzed with the SPSS version 24 software. Results: Eleven out of twenty-five aEEG recordings were abnormal; other patients showed normal aEEGs. The most common clinical and neurological manifestations were seizure (68%) and hypotonia (28%); the mortality rate was 12%. No significant correlation was observed between aEEG findings and gender, age, familial relation, outcome, ultrasound result, type of seizure, and underlying disease. Conclusion: Studies showed variable sensitivity and specificity values for aEEG. aEEG cannot be recommended as the only way to diagnose and manage seizures in neonates. However, Good accessibility and ease of working with aEEG promote a tendency to use this procedure as a screening tool.

Novel homozygous frameshift variant in the ATCAY gene in an Iranian patient with Cayman cerebellar ataxia; expanding the neuroimaging and clinical features: a case report.

BACKGROUND: Pathogenic variants in the ATCAY gene are associated with a rare autosomal recessive disorder called Cayman cerebellar ataxia. Affected individuals display psychomotor retardation, cerebellar dysfunction, nystagmus, intention tremor, ataxic gait and dysarthric in some cases. CASE PRESENTATION: Whole exome sequencing was performed for a 21-month-old girl suffering from developmental delay specifically in motor and language aspects, hypotonia, nystagmus, pes planus and strabismus. The detected variant in the patient was confirmed by family segregation analysis by Sanger sequencing in both of her parents. Previously three homozygous variants in the ATCAY gene (missense, splice site and frameshift deletion) have been reported in patients with Cayman cerebellar ataxia. Here we report the fourth homozygous variant and the second homozygous frameshift deletion in this gene to be associated with autosomal recessive Cayman cerebellar ataxia. CONCLUSION: The identification of this novel homozygous frameshift deletion in the ATCAY gene expands our understanding of the genetic landscape underlying Cayman cerebellar ataxia. Furthermore, the occurrence of this variant in Iran, in addition to Pakistan, signifies the importance of considering genotypic and phenotypic factors beyond ethnicity when studying this disorder. These findings contribute to the ongoing efforts to unravel the molecular basis of Cayman cerebellar ataxia and improve diagnostic approaches and potential therapeutic interventions.

Neurologic Manifestations of Coronavirus Disease 2019 in Children: An Iranian Hospital-Based Study.

BACKGROUND: COVID-19 infection and its neurological manifestations were seen in children although less common than adults. The aim of this study was to determine the frequency of different types of neurologic findings of hospitalized children with COVID-19. ]. METHODS: This retrospective study was performed on hospitalized pediatric patients aged≤18 years with confirmed SARS-CoV-2 at Children's Medical Center Hospital. Neurological manifestations were defined as the presence of any of the following symptoms: seizure, altered mental status, behavioral/personality change, ataxia, stroke, muscle weakness, smell and taste dysfunctions, and focal neurological disorders. RESULTS: Fifty-four children with COVID-19 were admitted and their mean age was 6.94±4.06 years. Thirty-four of them (63%) were male. The most frequent neurological manifestation was seizure (19 [45%]) followed by muscle weakness (11 [26%]), loss of consciousness (10 [23%]), and focal neurological disorders (10 [23%]). Other neurological manifestations consisted of headache (n=7), movement disorders (n=6), behavioral/personality change (n=5), ataxia (n=3), and stroke (n=3). Twenty-nine percent of our patients had leukocytosis. A neutrophil count above 70% was seen in 31% of participants. Among our patients, 81% had a positive reverse-transcription polymerase chain reaction (RT-PCR) test for SARS-CoV-2. CONCLUSION: During the current pandemic outbreak, hospitalized children with COVID-19 should be evaluated for neurological signs because it is common among them and should not be under-estimated.

Phenotype and genotype heterogeneity of PLA2G6-associated neurodegeneration in a cohort of pediatric and adult patients.

BACKGROUND: Phospholipase-associated neurodegeneration (PLAN) caused by mutations in the PLA2G6 gene is a rare neurodegenerative disorder that presents with four sub-groups. Infantile neuroaxonal dystrophy (INAD) and PLA2G6-related dystonia-parkinsonism are the main two subtypes. In this cohort, we reviewed clinical, imaging, and genetic features of 25 adult and pediatric patients harboring variants in the PLA2G6. METHODS: An extensive review of the patients' data was carried out. Infantile Neuroaxonal Dystrophy Rating Scale (INAD-RS) was used for evaluating the severity and progression of INAD patients. Whole-exome sequencing was used to determine the disease's underlying etiology followed by co-segregation analysis using Sanger sequencing. In silico prediction analysis based on the ACMG recommendation was used to assess the pathogenicity of genetic variants. We aimed to survey a genotype-genotype correlation in PLA2G6 considering all reported disease-causing variants in addition to our patients using the HGMD database and the chi-square statistical approach. RESULTS: Eighteen cases of INAD and 7 cases of late-onset PLAN were enrolled. Among 18 patients with INAD, gross motor regression was the most common presenting symptom. Considering the INAD-RS total score, the mean rate of progression was 0.58 points per month of symptoms (Standard error 0.22, lower 95% - 1.10, and upper 95% - 0.15). Sixty percent of the maximum potential loss in the INAD-RS had occurred within 60 months of symptom onset in INAD patients. Among seven adult cases of PLAN, hypokinesia, tremor, ataxic gate, and cognitive impairment were the most frequent clinical features. Various brain imaging abnormalities were also observed in 26 imaging series of these patients with cerebellar atrophy being the most common finding in more than 50%. Twenty unique variants in 25 patients with PLAN were detected including nine novel variants. Altogether, 107 distinct disease-causing variants from 87 patient were analyzed to establish a genotype-phenotype correlation. The P value of the chi-square test did not indicate a significant relationship between age of disease onset and the distribution of reported variants on PLA2G6. CONCLUSION: PLAN presents with a wide spectrum of clinical symptoms from infancy to adulthood. PLAN should be considered in adult patients with parkinsonism or cognition decline. Based on the current knowledge, it is not possible to foresee the age of disease onset based on the identified genotype.

Spinal Muscular Atrophy with Progressive Myoclonic Epilepsy (SMA-PME): three new cases and review of the mutational spectrum.

BACKGROUND: Spinal muscular atrophy (SMA) could be classified as 5q and non-5q, based on the chromosomal location of causative genes. A rare form of non-5q SMA is an autosomal-recessive condition called spinal muscular atrophy with progressive myoclonic epilepsy (SMA-PME), phenotypically characterized by myoclonic and generalized seizures with progressive neurological deterioration. SMA-PME is a clinically heterogeneous disorder that arises from biallelic pathogenic variants in ASAH1 gene. METHODS: Following clinical and primary laboratory assessments, whole-exome sequencing was performed to detect the disease-causing variants in three cases of SMA-PME from different families. Also, Multiplex ligation-dependent probe amplification (MLPA) was employed for determining the copy numbers of SMN1 and SMN2 genes to rule out 5q SMA. RESULTS: Exome sequencing revealed two different homozygous missense mutations (c.109 C > A [p.Pro37Thr] or c.125 C > T [p.Thr42Met]) in exon 2 of the ASAH1 gene in the affected members of the families. Sanger sequencing of the other family members showed the expected heterozygous carriers. In addition, no clinically relevant variant was identified in patients by MLPA. CONCLUSION: This study describes two different ASAH1 mutations and the clinical picture of 3 SMA-PME patients. In addition, previously reported mutations have been reviewed. This study could help to fortify the database of this rare disease with more clinical and genomic data.

Evaluation of patients presenting with febrile seizures in an Iranian referral hospital: emphasis on the frequency of meningitis and co-infections.

INTRODUCTION: Febrile seizures are one of the most common diseases that physicians encounter in pediatric emergency departments. Two important aspects of managing patients presenting with a febrile seizure are meningitis exclusion and co-infection investigation. This study was designed to determine any infection that occurs concomitantly with a febrile seizure episode and also to assess the frequency of meningitis among children presenting with febrile seizures. METHODS: This retrospective cross-sectional study was conducted at the Children's Medical Center, an Iranian pediatric referral hospital. All patients aged 6 months to 5 years presenting with febrile seizures from 2020 to 2021 were included. Patients' data were collected from the medical report files. The presence of respiratory, gastrointestinal, and urinary infections was evaluated. Moreover, the detection of SARS-CoV-2 using reverse transcription polymerase chain reaction (RT-PCR) was performed for suspicious cases. The results of urine and stool analysis, as well as blood, urine, and stool cultures were checked. The frequency of lumbar puncture (LP) performance and its results were studied. The relationship between white blood cells (WBC), erythrocyte sedimentation rate (ESR), and C-reactive protein in meningitis was evaluated. RESULTS: A total of 290 patients were referred to the Children's Medical Center, Tehran, Iran, due to fever and seizures. The mean age of the patients was 21.5 ± 13.0 months, and 134 (46.2%) were female. Out of 290 patients, 17% presented with respiratory infections. Nasopharyngeal SARS-CoV-2 RT-PCR was requested for 50 patients (17%), of which nine (3%) were reported positive and two patients had multi-inflammatory syndrome in children (MIS-C). Fever without local signs, gastroenteritis, and urinary tract infections were found in 40%, 19%, and 14% of the patients, respectively. LP was requested for 97 participants (33.4%) to evaluate central nervous system infection, of which 22 cases were suggestive of aseptic meningitis. Among laboratory tests, leukocytosis was significantly related to aseptic meningitis (odds ratio = 11.1, 95% CI = 3.0- 41.5). The blood culture testing result was positive in seven patients; all of them were due to skin contamination. CONCLUSION: Evaluation of patients for possible meningitis is necessary for febrile seizure management. Although the prevalence of bacterial meningitis in these patients is not high, according to this study and other studies conducted in Iran, aseptic meningitis, especially after Measles, Mumps, and Rubella (MMR) vaccination should be considered. Leukocytosis and increased CRP can predict the occurrence of aseptic meningitis in these patients. However, further studies with a larger sample size are highly recommended. Moreover, during the COVID-19 pandemic, it is recommended to pay attention to an acute COVID-19 infection or evidence of MIS-C in children with fever and seizure.

Efficacy and safety of miglustat in the treatment of GM2 gangliosidosis: A systematic review.

BACKGROUND: Since the results of previous studies regarding the safety and efficacy of miglustat in GM2 gangliosidosis (GM2g) were inconsistent, we aimed to assess miglustat therapy in GM2g patients. METHODS: This study followed the latest version of PRISMA. We included the observational or interventional studies reporting GM2g patients under miglustat therapy by searching PubMed, Web of Science, and Scopus. Data extracted included the natural history of individual patient data, as well as the safety and efficacy of miglustat in GM2g patients. The quality assessment was performed using the Joanna Briggs Institute Critical Appraisal checklist. RESULTS: A total of 1023 records were identified and reduced to 621 after removing duplicates. After screening and applying the eligibility criteria, 10 articles and 2 abstracts met the inclusion criteria. Overall, the studies represented 54 patients with GM2g under treatment with miglustat and 22 patients with GM2g in the control group. Among patients with available data, 14 and 54 have been diagnosed with Sandhoff disease and Tay-Sachs disease, respectively. Patients included in this review consisted of 23 infantile, 4 late-infantile, 18 juvenile, and 31 adult-onset GM2g. CONCLUSIONS: Although miglustat should not be considered a definite treatment for GM2g, it appears that patients, particularly those with infantile or late-infantile GM2g, could benefit from miglustat therapy to some extent. We also make some suggestions regarding future studies presenting their findings in a standard format to facilitate pooling the available data in such rare diseases for a more comprehensive conclusion.

Expanding the genetic spectrum of giant axonal neuropathy: Two novel variants in Iranian families.

BACKGROUND: Giant axonal neuropathy (GAN) is a progressive childhood hereditary polyneuropathy that affects both the peripheral and central nervous systems. Disease-causing variants in the gigaxonin gene (GAN) cause autosomal recessive giant axonal neuropathy. Facial weakness, nystagmus, scoliosis, kinky or curly hair, pyramidal and cerebellar signs, and sensory and motor axonal neuropathy are the main symptoms of this disorder. Here, we report two novel variants in the GAN gene from two unrelated Iranian families. METHODS: Clinical and imaging data of patients were recorded and evaluated, retrospectively. Whole-exome sequencing (WES) was undertaken in order to detect disease-causing variants in participants. Confirmation of a causative variant in all three patients and their parents was carried out using Sanger sequencing and segregation analysis. In addition, for comparing to our cases, we reviewed all relevant clinical data of previously published cases of GAN between the years 2013-2020. RESULTS: Three patients from two unrelated families were included. Using WES, we identified a novel nonsense variant [NM_022041.3:c.1162del (p.Leu388Ter)], in a 7-year-old boy of family 1, and a likely pathogenic missense variant [NM_022041.3:c.370T>A (p.Phe124Ile)], in two affected siblings of the family 2. Clinical examination revealed typical features of GAN-1 in all three patients, including walking difficulties, ataxic gait, kinky hair, sensory-motor polyneuropathy, and nonspecific neuroimaging abnormalities. Review of 63 previously reported cases of GAN indicated unique kinky hair, gait problem, hyporeflexia/areflexia, and sensory impairment were the most commonly reported clinical features. CONCLUSIONS: One homozygous nonsense variant and one homozygous missense variant in the GAN gene were discovered for the first time in two unrelated Iranian families that expand the mutation spectrum of GAN. Imaging findings are nonspecific, but the electrophysiological study in addition to history is helpful to achieve the diagnosis. The molecular test confirms the diagnosis.

The First Report of Iranian Registry of Patients with Spinal Muscular Atrophy.

BACKGROUND: Insufficient amounts of survival motor neuron protein is leading to one of the most disabling neuromuscular diseases, spinal muscular atrophy (SMA). Before the current study, the detailed characteristics of Iranian patients with SMA had not been determined. OBJECTIVE: To describe the key demographic, clinical, and genetic characteristics of patients with SMA registered in the Iranian Registry of SMA (IRSMA). METHODS: IRSMA has been established since 2018, and the demographic, clinical, and genetic characteristics of patients with SMA were recorded according to the methods of treat neuromuscular disease (TREAT-NMD) project. RESULTS: By October 1, 2022, 781 patients with 5q SMA were registered. Of them, 164 patients died, the majority of them had SMA type 1 and died during the first 20 months of life. The median survival of patients with type 1 SMA was 23 months. The consanguinity rate in 617 alive patients was 52.4%, while merely 24.8% of them had a positive family history. The most common type of SMA in live patients was type 3. Morbidities were defined as having scoliosis (44.1%), wheelchair dependency (36.8%), tube feeding (8.1%), and requiring mechanical ventilation (9.9%). Most of the registered patients had a homozygous deletion of SMN1, while the frequency of patients with higher copy numbers of SMN2, was less in more severe types of the disease. Earlier onset of the disease was significantly seen in patients with lower copy numbers of SMN2. The neuronal apoptosis inhibitory protein (NAIP) gene deletion was associated with a higher incidence of more severe types of SMA, higher dependency on ventilators, tube feeding, and earlier onset of the disease. CONCLUSIONS: The IRSMA is the first established Iranian nationwide registry of patients with SMA. Using this registry, decision-makers, researchers, and practitioners can precisely understand the epidemiology, characteristics, and genetics of patients with SMA in Iran.

A comprehensive overview of SMN and NAIP copy numbers in Iranian SMA patients.

Spinal muscular atrophy (SMA) is among the most common autosomal recessive disorders with different incidence rates in different ethnic groups. In the current study, we have determined SMN1, SMN2 and NAIP copy numbers in an Iranian population using MLPA assay. Cases were recruited from Genome-Nilou Laboratory, Tehran, Iran and Pars-Genome Laboratory, Karaj, Iran during 2012-2022. All enrolled cases had a homozygous deletion of exon 7 of SMN1. Moreover, except for 11 cases, all other cases had a homozygous deletion of exon 8 of SMN1. Out of 186 patients, 177 (95.16%) patients showed the same copy numbers of exons 7 and 8 of SMN2 gene. In addition, 53 patients (28.49%) showed 2 copies, 71 (38.17%) showed 3 copies and 53 patients (28.49%) showed 4 copies of SMN2 gene exons 7 and 8. The remaining 9 patients showed different copy numbers of exons 7 and 8 of SMN2 gene. The proportions of SMA patients with different numbers of normal NAIP were 0 copy in 73 patients (39.24%), 1 copy in 59 patients (31.72%), 2 copies in 53 patients (28.49%) and 4 copies in one patient (0.5%). These values are different from values reported in other populations. Integration of the data of the SMN1/2 and NAIP genes showed 17 genotypes. Patients with genotype 0-0-3-3-1 (0 copies of SMN1 (E7,8), 3 copies of SMN2 (E7,8) and 1 copy of NAIP (E5)) were the most common genotype in this study. Patients with 0-0-2-2-0 genotype were more likely to have type I SMA. The results of the current study have practical significance, particularly in the genetic counseling of at-risk families.

Expanding the neuroimaging findings of guanidinoacetate methyltransferase deficiency in an Iranian girl with a homozygous frameshift variant in the GAMT.

Guanidinoacetate methyltransferase deficiency (GAMTD) is a treatable neurodevelopmental disorder with normal or nonspecific imaging findings. Here, we reported a 14-month-old girl with GAMTD and novel findings on brain magnetic resonance imaging (MRI).A 14-||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||month-old female patient was referred to Myelin Disorders Clinic due to onset of seizures and developmental regression following routine vaccination at 4 months of age. Brain MRI, prior to initiation of treatment, showed high signal intensity in T2-weighted imaging in bilateral thalami, globus pallidus, subthalamic nuclei, substantia nigra, dentate nuclei, central tegmental tracts in the brainstem, and posterior periventricular white matter which was masquerading for mitochondrial leukodystrophy. Basic metabolic tests were normal except for low urine creatinine; however, exome sequencing identified a homozygous frameshift deletion variant [NM_000156: c.491del; (p.Gly164AlafsTer14)] in the GAMT. Biallelic pathogenic or likely pathogenic variants cause GAMTD. We confirmed the homozygous state for this variant in the proband, as well as the heterozygote state in the parents by Sanger sequencing.MRI features in GAMTD can mimic mitochondrial leukodystrophy. Pediatric neurologists should be aware of variable MRI findings in GAMTD since they would be misleading to other diagnoses.