This review focuses on chemotherapy-induced polyneuropathy, which is a fairly common side effect and affects not only the quality of life of patients with malignancies, but can also lead to a change in patient management tactics, namely dose modification, delay of drug administration to complete cessation of treatment, which threatens the life of the patient. Chemotherapy-induced polyneuropathy is based on different mechanisms of damaging effects depending on the type of cytotoxic agent. The most neurotoxic drugs are platinum drugs, taxanes, periwinkle alkaloids, bortezomib, and thalidomide. As a result of neurotoxic effects, damage occurs to thin and thick fibers of peripheral nerves. However, it is still a mystery why one patient develops manifestations of neurotoxicity and another does not. Therefore, the modern medical community is faced with the urgent question of further study of the mechanisms of development, risk factors, as well as the search for biomarkers and the development of prevention and treatment of chemotherapy-induced polyneuropathy. The results of studies on the mechanism of onset, clinic, diagnosis, prevention and treatment of chemotherapy-induced polyneuropathies are summarized.

Huntington’s disease is a serious inherited neurodegenerative disorder characterized by of motor, cognitive and psychiatric features. The disease is caused by an abnormally expanded CAG repeat expansion in the HTT gene and the production of mutant huntingtin protein.

The disease usually manifests in adulthood, but the manifestation in childhood and youth is also described, which is noted in 5–10 % of cases. The disease predominantly affects the neostriatum, resulting in a characteristic clinical picture.

The most promising approaches to etiotropic therapy of Huntington’s disease are a number of DNA- (CRISPR/Cas9 system) and RNA-directed methods (antisense oligonucleotides, RNA interference), methods that directly reduce the level of mutant gentingtin (chimera molecules), as well as approaches based on inactivating the DNA mismatch repair system using the FAN1 enzyme. 

Background. Duchenne muscular dystrophy (DMD) is a severe, progressive form of muscular dystrophy that occurs in children between one and three years of age. The disease is mainly characterized by weakness of the proximal muscles, which leads to difficulty in movement, and ultimately to complete disability. Becker muscular dystrophy (BMD) is a milder allelic form of the disorder characterized by late onset and slow progression. The cause of the development of DMD/BMD is mutations in the DMD gene, leading to a deficiency in the production of various isoforms of the dystrophin protein family. The most common mutations in case of DMD/BMD are gross deletions (55–65 %) and duplications (6–11 %) of one or several exons The remaining cases of DMD/BMD are due to small mutations (approximately 20–30 %). Depending on the methodological capabilities of the laboratory, the idea of the spectrum of mutations in the DMD gene changed, which is important in genetic counseling of patients and planning the therapy available today.

Aim. To analyze the spectrum of mutations in the DMD gene, including three time slices, depending on the methodological capabilities of the laboratory.

Materials and methods. We analyzed the spectrum of mutations in the DMD gene for a sample of 2957 patients admitted to the laboratory of DNA diagnostics of the Research Centre for Medical Genetics with a referral diagnosis of DMD/BMD. Depending on the time of treatment and the capabilities of the laboratory, patients were divided into three groups: 2008–2015, 2016–2018, 2019–2022.

Results. As a result of the study, the full range of mutations in the DMD gene was analyzed over three-time intervals, which makes it possible to get an idea of the distribution of mutation types in the sample among Russian patients. Regardless of the methodological capabilities of the laboratory, the spectrum of mutations in the DMD gene remains biased relative to world data. At the moment, there is a significant decrease in the proportion of extended deletions (50.7–59.6 %), while the proportion of extended duplications (11.8–17.2 %) and small mutations (23.2–35.0 %) increased. We assume that the main reason for such features of the spectrum is ethnic and population differences.

Conclusion. Duchenne/Becker muscular dystrophy (DMD/BMD) is the most common form of muscular dystrophy, accounting for more than 50 % of all cases. Determination of the spectrum of mutations provides an understanding of their frequencies, which in the future may help patients in the appointment of therapy specific to a particular type of mutation. 

Background. Progressive muscular dystrophies (PMD) are a group of genetically heterogeneous diseases that manifest in the age range from early childhood to adulthood. Depending on the predominant topography of the muscular lesion, there are: limb-girdle, distal, oculopharyngeal, facial-shoulder-scapular-peroneal variants of PMD.

Aim. Creation of algorithms for the differential diagnosis of PMD with multiple topography of muscle lesions.

Materials and methods. We observed 192 patients aged 1.5 to 66 years with PMD with a debut after a period of normal motor development. The diagnosis was established on the basis of genealogical analysis, neurological examination, assessment of non-muscular manifestations, results of instrumental, biochemical molecular genetic studies.

Results. Four groups of patients were identified, differing in the topography of muscle damage and 19 genetic variants of PMD were diagnosed. An algorithm for diagnosing PMD that manifest after a period of normal motor development is proposed, which is based on the frequency of occurrence of individual genetic variants and their proportion in the analyzed sample, the presence of major mutations in causal genes, the features of phenotypic characteristics, the gender of the patient and the possibility of conducting etiopathogenetic therapy developed by for some genetic variants.

Conclusion. The use of the proposed algorithm in clinical practice can significantly reduce the economic and time costs for confirmatory molecular genetic diagnosis, and promptly recommend etiopathogenetic therapy for some genetic variants of this group of diseases. 

Background. Today, the issues of differential diagnosis of chronic hereditary and acquired demyelinating neuropathies are still relevant. The variety of phenotypic variants of chronic inflammatory demyelinating polyradiculoneuropathy and hereditary neuropathy with liability to pressure palsies, their remitting course and the non-specificity of neurophysiological changes necessitate the identification of clear markers that can help in the differential diagnosis of the neuropathies under discussion already at the stage of the analysis of the electroneuromyographic study data.

Aim. To determine neurophysiological differential diagnostic markers in the manifestation of chronic inflammatory demyelinating polyradiculoneuropathy and hereditary neuropathy with liability to pressure palsies.

Materials and methods. A retrospective analysis of the data of neurophysiological examination of 25 patients with hereditary neuropathy with liability to pressure palsies and 25 patients with chronic inflammatory demyelinating polyradiculoneuropathy.

Results. A combination of such indicators as the age of the onset of the disease <33 years, the latency of the dM-wave with m.ADM ><3.7 ms and with m.AH ><4.8 ms (AUROC >0.7), the value of the conduction velocity along of the motor fibers of the ulnar nerve at the level of the elbow joint <37.5 m/s (AUROC >0.8), the conduction velocity along of the sensory fibers of the median nerve at the level of the wrist <48 m/s (AUROC >0.8), absence of conduction block along the median nerve in any area, and also the presence along the ulnar nerve at the level of the elbow joint is characteristic of hereditary neuropathy with liability to pressure palsies and allows to exclude chronic inflammatory demyelinating polyradiculoneuropathy.

Conclusion. Neurophysiological markers have been identified that can help in the differential diagnosis of two chronic remitting demyelinating neuropathies: chronic inflammatory demyelinating polyradiculoneuropathy and hereditary neuropathy with liability to pressure palsies. However, only a combined analysis of clinical, anamnestic and paraclinical data makes it possible to establish a final diagnosis. 

Background. The use of rating scales and questionnaires is essential in an evaluation of disease course, treatment response, the disability level and quality of life in patients with chronic inflammatory demyelinating polyneuropathy. The Medical Research Council (MRC) scale and its modification Medical Research Council sum score (MRCss) are widely used for measurement of motor deficit in patients with neuromuscular disorders. However, its usage is limited by the absence of the validated version for Russian-speaking patients.

Aim. To validate MRCss scale in patients with chronic inflammatory demyelinating polyneuropathy with development of a Russian version.

Materials and methods. We enrolled 50 patients with chronic inflammatory demyelinating polyneuropathy (25 with typical chronic inflammatory demyelinating polyneuropathy and 25 with Lewis–Sumner syndrome). At the first step we conducted linguocultural ratification according to the standard protocol. At the second step the psychometric parameters were evaluated, such as reliability, validity and sensitivity.

Results. The developed Russian version of MRCss scale demonstrated the high level of reliability, validity and sensitivity.

Conclusion. As a result, we developed a validated Russian version of MRCss scale, recommended for clinical practice and research. 

Background. Spinal muscular atrophy (SMA) affects 1 in 11,000 people. Until 2016, this was considered an incurable disease, but after the approval of nusinersen, the situation has changed. The efficacy of nusinersen therapy is also known in adult patients, although research is limited due to the majority of studies in infants and children. Nusinersen has been included in the list of “Vital and Essential Medicines” since 2021.

Aim. To analyze the experience of using nusinersen as a pathogenetic therapy for patients over 18 years of age with SMA 5q in the Republic of Bashkortostan.

Materials and methods. We examined eight patients receiving pathogenetic therapy with nusinersen (SMA type 2 – 34.5 %, SMA type 3 – 65.5 %). The Hammersmith Functional Motor Scale Expanded (HFMSE) and the Revised Upper Limb Module (RULM) were used for evaluating the effectiveness of therapy.

Results. The median increase on the HFMSE scale was +2 points (7.5, with the initial 5.5) and on the RULM scale – +4.5 points (17 points, with the initial 12.5). Clinically, this was expressed in an increase in muscle strength, an increase in daily activity; a decrease in bulbar, respiratory and vegetative disorders can also be noted. Subjectively, positive dynamics was noted in the increase in working capacity, improvement of the emotional background.

Conclusion. The use of the drug nusinersen in adult patients with SMA 5q in some cases provides clinical improvement. The presence of an “overall response” is defined as clinically significant change in one assessed measure of motor function.