Neurofibromatosis type 1 is a multisystem genetic disorder associated with an increased risk of benign and malignant tumors due to mutations in the NF1 gene. Clinical manifestations of the disease vary and depend on the patient’s age. One of the most common complications of neurofibromatosis type 1 is plexiform neurofibroma – a benign tumor affecting peripheral nerves. For a long time, there had been no standard care for such patients in the Russian Federation; treatment of plexiform neurofibromas was usually limited to symptomatic therapy and repeated surgical interventions. In the last few years, treatment approach to patients with neurofibromatosis type 1 complicated by plexiform neurofibromas changed, since a targeted drug, selumetinib became available. In clinical trials, 65 % of children receiving selumetinib demonstrated a partial response (reduction in the volume of plexiform neurofibromas by 20 % or more) for more than 3 cycles (months), 56 % of children demonstrated a long-term response (a year or more) without traumatic surgical interventions. In our country, more than 200 children have already received selumetinib under the early access program after its registration in the Russian Federation (January 2021). In Yu.E. Veltischev Research and Clinical Institute for Pediatrics and Pediatric Surgery, the drug was prescribed to 104 patients; of them, 54 patients were followed up between April 2021 and October 2023. The most common adverse events associated with selumetinib in our patients included skin rash (acne/maculopapular rash or eczema), dry skin, hair discoloration and hair loss, paronychia, and an asymptomatic elevation of creatine phosphokinase. This article provides information on the most common adverse events of selumetinib therapy, preventive measures, and recommendations for patient follow-up.

Background. The problem of antiepileptic therapy in children remains highly relevant due to the insufficient efficacy of standard drugs, adverse events, and limitations of clinical guidelines.
Aim. To assess the efficacy, tolerability, and continuation of zonisamide (Zonegran) therapy in children with epilepsy.
Materials and methods. This retrospective multicenter study was conducted in epileptology centers in various regions of the Russian Federation, including Moscow, Novosibirsk, Krasnodar, Tyumen, Krasnoyarsk, Voronezh, Ryazan). We included 340 patients under the age of 18 (202 boys and 138 girls) with various epileptic syndromes receiving zonisamide (mean age was 10.63 years). Zonisamide was administered to patients with the following epileptic syndromes: age-dependent self-limited focal epilepsy of childhood (n = 49; 14 %) structural focal epilepsy (n = 102; 30 %), focal epilepsy of childhood with structural brain changes and benign epileptiform discharges of childhood visualized at electroencephalography (n = 38; 11.2 %), idiopathic generalized epilepsy (n = 23; 6.7 %), developmental and epileptic encephalopathies (n = 44; 12.9 %) (including developmental and epileptic encephalopathies with spike-and-wave activation during sleep (n = 23; 6.7 %)), Lennox–Gastaut syndrome and infantile epileptic spasms syndrome (n = 32; 9.4 %), genetic epilepsy with generalized and focal seizures (n = 81; 23.8 %). The type of the seizures was distributed as follows: focal motor (n = 205), bilateral tonic-clonic (n = 192), generalized (n = 197), including generalized convulsive (n = 44), tonic (n = 70), atonic (n = 2), myoclonic (n = 26), epileptic spasms (n = 36), absence seizures (n = 19). One patient could have more than one type of seizures. Magnetic resonance imaging demonstrated some changes in 185 patients, whereas 117 patients had no magnetic resonance imaging changes. Thirty-eight patients did not undergo magnetic resonance imaging as they had no indications to it. The most common structural epileptogenic changes were the consequences of perinatal lesions manifesting as cystic-gliotic transformation, atrophy (125 cases in total); less common changes included focal cortical dysplasia, developmental abnormalities (such as polymicrogyria, lissencephaly, holoprosencephaly), mesial temporal sclerosis, and tumors. Zonegran (zonisamide) as an additional therapy was administered at a dose of 3–8 mg/kg/day (mean dose 5 mg/kg/day) to 321 patients.
Results. Zonegran (zonisamide) therapy was effective in 257 (75.6 %) of patients; remission was achieved in 174 patients (67.7 %), while reduced seizure frequency (50 % and greater) was registered in 83 patients (32.3 %). A total of 72 patients (21.2 %) reported no adverse events. Twenty participants (5.8 %) had some adverse events; in 4 cases, they were resolved after dosage decrease; in 16 cases, treatment with zonisamide was discontinued.
Conclusion. Zonegran (zonisamide) is effective for comprehensive treatment of both focal and generalized epilepsy in children*.

Among rather rare but extremely interesting and important conditions, myelitis stands apart due to its complexity and diversity of clinical manifestations. In this article, in addition to the well-known data on this group of diseases, we present the results of the analysis of eight cases of myelitis, which may serve as a starting point for the development of more effective and streamlined strategies in diagnosis and treatment. It may also contribute to deeper understanding of difficult cases in neurological practice.

Pontocerebellar hypoplasia caused by the TSEN54 mutation is a severe hereditary disease with an autosomal recessive mode of inheritance, which is characterized by a combination of epileptic encephalopathy, motor disorders in the form of spasticity and hyperknesis, dysphagia and central respiratory failure. At birth there may be multiple joint contractures, muscle hypotonia, and central respiratory failure. Epilepsy occurs in 82 % of cases. Seizures may begin after birth, with an average age of onset of 2.5 years. Various types of seizures are noted (febrile seizures, bilateral tonic-clonic, atypical absence, myoclonic, tonic, focal and atonic seizures), usually resistant to antiepileptic drugs. Magnetic resonance imaging reveals hypoplasia of the pons and cerebellum, which makes it possible to distinguish this disease from cerebral palsy. In the literature there are few descriptions of the clinical picture and electroencephalogram of patients. In this regard, our description of 3 cases of epilepsy and electroencephalographic data in patients with TSEN54 mutation (all female) is of interest to child neurologists and epileptologists.

Diffuse leptomeningeal glioneuronal tumor was introduced into the World Health Organization classification of central nervous system tumors in 2016. According to the actual World Health Organization classification of central nervous system tumors emerged in 2021, its reliable verification requires the combination of specific pathomorphological and molecular-genetic features as well as data of the neuroimaging. Typically occurring in children and adolescents these tumors are characterized by widespread diffuse leptomeningeal dissemination along the neuraxis and demonstrate a tendency to abundant contrast enhancement resulting in a specific magnetic resonance imaging appearance. Despite this, and the rather rare incidence, a number of publications have reported an increasing number of atypical cases of diffuse leptomeningeal glioneuronal tumor suggesting that the spectrum of clinical manifestations, molecular-genetic and radiological criteria of this tumor is not fully disclosed and requiring further comprehensive investigations. The article presents the experience of complex, interdisciplinary diagnosis of diffuse leptomeningeal glioneuronal tumor with atypical radiological picture in a child with focal structural epilepsy.

The etiology of cerebral palsy in children with intrauterine hypotrophy at birth and developmental delay is often explained by chronic intrauterine hypoxia. However, children with muscle hypotonia and developmental delay require genetic examination.
The aim of this study is to report a case of mitochondrial disease caused by FBXL4 gene mutations and to identify main diagnostic criteria for mitochondrial DNA (mtDNA) depletion syndromes (MDS) in early childhood.
Mitochondrial DNA depletion syndrome-13 is associated with FBXL4 gene mutations located in the 6q16.1–q16.27 locus. This disorder was first described in 2013 by P.E. Bonnen and X. Gai independently. MDS are a clinically and genetically heterogeneous group of diseases inherited by an autosomal recessive type and caused by mutations in genes that support the biogenesis and integrity of mtDNA.
Encephalomyopathic mtDNA depletion syndrome-13 (MTDPS13) (OMIM: 615471) is an exceedingly rare autosomal recessive disease caused by biallelic mutations in the FBXL4 gene (MIM: 605654) with an estimated prevalence of 1 case per 100,000– 400,000 newborns. The disease onset is usually observed in the neonatal period; 75 % of patients develop symptoms by the age of 3 months. In the majority of cases, mtDNA depletion syndrome-13 manifests itself in the early neonatal period; however, in some patients, the disease onset was registered by the age of 24 months. The disease is characterized by encephalopathy, hypotension, lactic acidosis, severe developmental delay, and changes in the area of basal ganglia revealed by magnetic resonance imaging of the brain. FBXL4-related encephalomyopathy is a multisystem disease primarily affecting the central nervous system, heart, and liver. It is characterized by different clinical manifestations such as lactic acidosis, developmental delay, generalized hypotension, nutritional disorders, and growth retardation. Some patients demonstrate specific facial features, including prominent forehead, sinus-shaped folds, thick eyebrows, long eyelashes, epicanthus, short eye slits, hypertelorism, wide and depressed nose bridge, long and smooth labial groove, thin upper lip, and low-set ears.
The disease prognosis is extremely poor; most children die before the age of 4 years. Approximately half of the patients suffer from microcephaly and hyperammonemia. The outcome varies; death was reported in 30 % of cases. Mean time to death was 3 years (median – 2 years).
The diagnosis is crucial for medical and genetic counseling and possible prenatal diagnosis.