Abstract The congenital dysferlinopathy phenotype is the rarest and earliest manifestation variant, described in two closely related Spanish and Turkish families, with a homozygous pathogenic frameshift variant in exon 26 of the DYSF gene. This article presents a 1.6-year-old patient from a consanguineous Uzbek family with a clinical diagnosis of congenital dysferlinopathy phenotype and Marinesco–Sjögren syndrome with transient postnatal hypotonia, motor development delay, muscle weakness in the flexors of the neck and proximal limbs, convergent strabismus, cerebellar truncal ataxia, minimal intention tremor of the upper limbs, a slight increase in the levels of creatinine phosphokinase (CK) to 353 U/L (2.4×N) and that of myoglobin to 40 µg/mL (2×N). Magnetic resonance imaging (MRI) revealed pronounced edematous changes in the gastrocnemius muscle on short tau inversion recovery (STIR). MRI signs of minimal fat replacement and hypotrophy were noted in the medial and posterior thigh and gastrocnemius muscles. MRI of the head revealed hypoplasia of the vermis and cerebellar hemispheres. Whole-exome sequencing revealed compound heterozygous DYSF variants: NM_001130987.2:c.1000 C > T (p.(Arg334Trp)) and NM_001130987.2:c.518 C > T (p.(Thr173Met)), and a previously described homozygous SIL1 variant NM_022464.5:c.178G > T (p.(Glu60Ter)). Histopathological examination revealed minimal signs of myopathy and dysferlin in only 1% of the muscle fibers. At the ultrastructural level, signs of dysferlinopathy and Marinesco–Sjögren syndrome were detected. This clinical case is an example of the cosegregation of two diseases that mutually potentiate damage to skeletal muscles.

Dysferlinopathy represents an orphan disease within the spectrum of progressive muscular dystrophies, occurring at a frequency of 1 to 9 cases per 1.000.000 individuals (Orphanet, 2024). It arises from mutations in the DYSF gene (OMIM 603009, 2p13, NM_003494.4), which is responsible for coding the transmembrane protein dysferlin. Dysferlin plays a critical role in the repair of muscle fiber membranes and the cellular processes of skeletal muscle regeneration. Although the molecular mechanisms of dysferlin-mediated repair are under active investigation, reports on the ultrastructural alterations in human skeletal muscles due to dysferlin deficiency are sparse. OBJECTIVE:To identify the ultrastructural pathomorphological features of skeletal muscles in 6 patients with dysferlinopathy. MATERIAL AND METHODS:This study presents pathomorphological, immunohistochemical, and ultrastructural data from skeletal muscle biopsies of 6 patients with molecularly confirmed dysferlinopathy. RESULTS:Examination of paraffin-embedded sections of the anterior tibialis and vastus lateralis muscles, stained with hematoxylin and eosin, identified a primarily myopathic pattern of skeletal muscle injury. Immunohistochemical staining with dysferlin antibodies revealed the absence of the protein in muscle tissue compared to the positive control. Transmission electron microscopy has revealed ultrastructural alterations characteristic of dysferlinopathy, although not specific, including thickening and fragmentation of the basal membrane, thinning and lysis of myofibrils, folding and disruptions of the sarcolemma, destruction of mitochondria, and, newly described in this disease, necrosis of myosatellite cells and telocytes in skeletal muscles. CONCLUSION:Despite the non-specificity of the identified ultrastructural alterations, electron microscopy of skeletal muscle biopsies in dysferlinopathy can provide additional information about the mechanisms underlying the disease development. The finding of myosatellite cell and telocyte necrosis indicates the impairment of skeletal muscle regenerative capacity, which may be a novel link in the pathogenesis of dysferlinopathy.

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Objective: Scientists need cell models from human tissues to develop methods of gene therapy and genome editing for monogenic diseases. It is preferable to use minimally invasive methods to obtain samples; these tissues can be applied for further screening to select the most effective approach to restore the synthesis of the target protein. Methods: We used the CRISPR/Cas9-SAM transcriptional activation system, which ensures expression of the DYSF gene in HEK293Т cells, as well as in fibroblasts from patients with dysferlinopathy (c.2779delG (Ala927LeufsX21)). Results and Discussion: After targeted activation of DYSF, it was possible to detect the main gene products: mRNA and protein (HEK293Т_ТА) and mRNA (fibroblasts). Conclusions: Transcriptionally activated dysferlin-deficient fibroblasts and HEK293 cells can be used to evaluate the in vitro efficacy of gene therapy for dysferlinopathies.

Calpainopathy, or limb-girdle muscular dystrophy type R1/2A (LGMDR1/2A), is the most prevalent form of LGMD, comprising about 32% of all cases. The disease is caused by mutations in the CAPN3 gene, leading to dysfunction of the corresponding protein-an enzyme critical for muscle fiber cytoskeleton remodeling and protein signaling regulation through selective proteolysis. Clinical manifestations demonstrate significant phenotypic polymorphisms, ranging from oligosymptomatic forms to severe early-onset cases, with the loss of ambulation occurring 10-25 years after disease onset. A characteristic feature is predominantly symmetrical involvement of limb and trunk muscles, leading to early mobility loss, disability, and reduced work capacity. Noninvasive imaging can suggest dystrophic muscle disease but requires differentiation from other myopathies. Confirming the diagnosis involves histological, immunological, and molecular genetic studies to identify calpain-3 activity or CAPN3 gene expression alterations. Currently, no targeted or etiological therapies are available for calpainopathy. Treatment focuses on symptom management, complication prevention, and slowing disease progression. Preclinical research demands the development of an appropriate animal model that displays disease phenotypes mirroring those observed in humans. Preclinical and clinical research are also investigating therapeutic options, including the use of drugs that have proven effective in other myopathies and genome editing via transgenic CAPN3 delivery to restore protein activity. Gene therapy has shown promise in murine models, but safety concerns, particularly systemic toxicity affecting the heart and other organs, remain significant. This review comprehensively analyzes the clinical features, diagnostic approaches, and advancements in modeling and therapeutic development for calpainopathy.

Wilson-Konovalov disease is a severe progressive life-threatening hereditary autosomal recessive disease from the group of metabolic disorders with multisystem manifestations. Laboratory diagnostics is the basis for early diagnosis and timely initiation of treatment, monitoring the course of the disease, selecting and evaluating the effectiveness of therapy, minimizing its side effects. Modern approaches to the diagnosis and monitoring of Wilson’s disease using laboratory research are presented in the article. Examples of phenotypic diagnosis and monitoring are demonstrated. When laboratory tests are used correctly, it is possible to approach personalized treatment of patients, increase the duration and improve their quality of life.

BACKGROUND:Dysferlinopathy is heritable progressive muscular dystrophy caused byDYSFmutation. Currently, although skeletal muscle pathology has been defined, only fragmentary and limited myocardium histopathology data are available. AIM:The study aimed to analyze the pathomorphological status of the myocardium in Bla/J mice models of dysferlinopathy at different ages. MATERIALS AND METHODS:Data from two experimental groups were analyzed: Bla/J mice withDYSFknockout on 3, 6, and 12 months old and control wild-type Balb/C mice aged 6 months. The expressions and patterns of dyeing of protein dysferlin in the immunofluorescent search method were analyzed. These were held such parameters of the histological characteristic of the myocardium of three dyeing protocols (hematoxylin and eosin, iron hematoxylin by Rego, and hematoxylin-basic fuchsin-picric acid by Lie), and morphometry of the parameters of the cardiomyocytes (length, width of cardiomyocytes, and nuclear perimeter). RESULTS:The immunofluorescent search method revealed high levels of dysferlin in the myocardium of the control group. Statistical analysis showed significant differences between Bla/J and Balb/C mice: the increasing length and width of cardiomyocytes in dysferlinopathy by 49.9% ((95% confidence interval, 45.9–57.4) and 35.6 (95% confidence interval, 32.9–37.9)), respectively. Nucleus perimeter was significantly reduced in the dysferlinopathy group with disease duration of 6 months (by 23.9 (95% confidence interval, 20.2–27.5) compared with the group with disease duration of 3 months and by 18.8% (95% confidence interval, 8.5–19.7)) and the control group. Consequently, progressive hypertrophy of cardiomyocytes, increasing deformation in cardiomyocytes, intercalated disk destruction, hypoxia features, and necrosis indication were observed, resulting in fibrosis. A pattern of cardiomyocyte size reduction dependent on the aging process was observed. CONCLUSIONS:Dysferlin deficiency leads to significant damage in the myocardium of Bla/J mice.

Background Dysferlinopathy is a phenotypically heterogeneous group of hereditary diseases caused by mutations in the DYSF gene. Early contractures are considered rare, and rigid spine syndrome in dysferlinopathy has been previously reported only once. Case presentation We describe a 23-year-old patient with Miyoshi myopathy with a rigid spine and multiple contractures, a rare phenotypic variant. The disease first manifested when the patient was 13 years old, with fatigue of the gastrocnemius muscles and the development of pronounced contractures of the Achilles tendons, flexors of the fingers, and extensors of the toes, followed by the involvement of large joints and the spine. Magnetic resonance imaging revealed signs of connective tissue and fatty replacement of the posterior muscles of the thighs and lower legs. Edema was noted in the anterior and medial muscle groups of the thighs, lower legs, and the multifidus muscle of the back. Whole genome sequencing revealed previously described mutations in the DYSF gene in exon 39 (c.4282 C > T) and intron 51 (c.5785-824 C > T). An immunohistochemical analysis and Western blot showed the complete absence of dysferlin protein expression in the muscle fibers. Conclusions This case expands the range of clinical and phenotypic correlations of dysferlinopathy and complements the diagnostic search for spine rigidity.

Dysferlinopathy is a phenotypically heterogeneous, inherited, progressive muscular dystrophy caused by mutations in the DYSF gene. Dysferlinopathy is marked by elevated serum creatine kinase (CK) and can in some cases manifest as hyperCKemia in asymptomatic or low-symptom states. Here, we describe the clinical signs and symptoms and laboratory and imaging results with quantitative MRI analysis of eight pediatric patients at asymptomatic and oligosymptomatic states of dysferlinopathy (aged 3-14 years). Seven of them with a same homozygous mutation and one with a compound heterozygous mutation in the DYSF gene. Based on this case series, we propose two stages of dysferlinopathy disease progression. The first state is asymptomatic hyperCKemia laboratory syndrome of myocytolysis, which is marked by an increase in CK (>1.5 times the upper limit of normal (ULN)) and lactic dehydrogenase (LDH). Second state (oligosymptomatic): increasing CK (2.7-12.6 × ULN), LDH, alanine aminotransferase (ALT), and myoglobin; minimal or moderate signs of fatty muscle infiltration, displacement of the center of support to the back of the foot during plantography; slight afterload fatigue of the calf muscles; slight decrease in muscle strength (imperceptible to the patient) and decrease in Achilles reflexes. Taken together, isolated hyperCKemia (asymptomatic stage) and oligosymptomatic patients form a single continuum of pre-manifest cases.

Background. Marcher’s digitalgia paresthetica is a neuropathy of the medial plantar proper digital nerve ( nervus digita lis plantaris proprii medialis halluci ) and in some cases is accompanied by the formation of Joplin’s neuroma. Despite the general population rarity, marcher’s digitalgia paresthetica is significantly common among the special military contingent, athletes and tourists. Aim . To assess the prevalence of medial digital nerve neuropathy among military personnel and to identify possible factors contributing to its development. Materials and methods . The study involved 125 male servicemen of the Russian Federation, with an average age 37 (37–40) years. A neurological examination was performed with a detailed assessment of sensory disorders in the lower extremities, electroneuromyography and ultrasound examination of the leg nerves. Results. In 83 cases, or 66 (55–76) %, of digitalgia paresthetica were identified. Among them asymptomatic – 51 people, or 61 (47–74) %. In 27 cases – 33 (21–47) % – violation of sensitivity was observed on one side. The maximum area of violation of the sensitivity of the innervation of the medial‑plantar surface of the big toes was determined in 57 cases – 68 (55–80) %. At the same time, in 14 (6–25) % of the examined, the distal part of the second toe was additionally involved. Conclusion. In our study, the hypothesis about the influence of the type of footwear, the average daily duration of wearing and the frequency of its forced removal on the likelihood of developing paresthetic digitalgia was not confirmed. It is important that doctors are informed about the possible development of this neuropathy and its benign course.

Dysferlinopathy treatment is an active area of investigation. Gene therapy is one potential approach. We studied muscle regeneration and inflammatory response after injection of an AAV-9 with a codon-optimized DYSF gene. A dual-vector system AAV.DYSF.OVERLAP with overlapping DYSF cDNA sequences was generated. Two AAV vectors were separately assembled by a standard triple-transfection protocol from plasmids carrying parts of the DYSF gene. Artificial myoblasts from dysferlin-deficient fibroblasts were obtained by MyoD overexpression. RT-PCR and Western blot were used for RNA and protein detection in vitro. A dysferlinopathy murine model (Bla/J) was used for in vivo studies. Histological assay, morphometry, and IHC were used for the muscle tissue analysis. Dysferlin was detected in vitro and in vivo at subphysiological levels. RT-PCR and Western Blot detected dysferlin mRNA and protein in AAV.DYSF.OVERLAP-transduced cells, and mRNA reached a 7-fold elevated level compared to the reference gene (GAPDH). In vivo, the experimental group showed intermediate median values for the proportion of necrotic muscle fibers, muscle fibers with internalized nuclei, and cross-sectional area of muscle fibers compared to the same parameters in the control groups of WT and Bla/J mice, although the differences were not statistically significant. The inverse relationship between the dosage and the severity of inflammatory changes in the muscles may be attributed to the decrease in the number of necrotic fibers. The share of transduced myofibers reached almost 35% in the group with the highest dose. The use of two-vector systems based on AAV is justified in terms of therapeutic efficacy. The expression of dysferlin at a subphysiological level, within a short observation period, is capable of inducing the restoration of muscle tissue structure, reducing inflammatory activity, and mitigating necrotic processes. Further research is needed to provide a more detailed assessment of the impact of the transgene and viral vector on the inflammatory component, including longer observation periods.

AbstractBackgroundDysferlinopathy has a high prevalence in relatively isolated ethnic groups where consanguineous marriages are characteristic and/or the founder effect exists. However, the frequency of endemic mutations in most isolates has not been investigated.MethodsThe prevalence of the pathological DYSF gene variant (NM_003494.4); c.200_201delinsAT, p. Val67Asp (rs121908957) was investigated in an isolated Avar population in the Republic of Dagestan. Genetic screenings were conducted in a remote mountainous region characterized by a high level of consanguinity among its inhabitants. In total, 746 individuals were included in the screenings.ResultsThis pathological DYSF gene variant causes two primary phenotypes of dysferlinopathy: limb‐girdle muscular dystrophy (LGMD) type R2 and Miyoshi muscular dystrophy type 1. Results indicated a high prevalence of the allele at 14% (95% confidence interval [CI]: 12–17; 138 out of 1518 alleles), while the allele in the homozygous state was detected in 29 cases—3.8% (CI: 2.6–5.4). The population load for dysferlinopathy was 832.3 ± 153.9 per 100,000 with an average prevalence of limb‐girdle muscular dystrophies ranging from 0.38 ± 0.38 to 5.93 ± 1.44 per 100,000.ConclusionA significant burden of the allele was due to inbreeding, as evidenced by a deficiency of heterozygotes and the Wright fixation index equal to 0.14 (CI 0.06–0.23).

Введение. Среди поясно-конечностных мышечных дистрофий (ПКМД) по частоте встречаемости дисферлинопатия занимает второе место в мире после кальпаинопатии. Заболевание характеризуется относительно поздней манифестацией, а сходная клиническая картина в группе ПКМД в ряде случаев создает значимые сложности в дифференциальной диагностике. Методом секвенирования нового поколения (NGS) можно быстро и эффективно определить вариант нуклеотидной последовательности гена DYSF, приводящий к нарушению синтеза белка дисферлина. Цель исследования: определить эффективность выявления вариантов нуклеотидных последовательностей в гене DYSF методом NGS у пациентов с клиническим диагнозом диферлинопатия и оценить возможности данного метода в дифференциальной диагностике ПКМД. Методы. Поиск генетических вариантов в гене DYSF производился у 157 пациентов при наличии клинических проявлений ПКМД, сопровождающихся повышением уровня креатинфосфокиназы (КФК) в 10-100 раз, манифестацией в возрасте 2-73 лет. У 27 пациентов выявлены изменения в последовательности гена DYSF. Методом Сэнгера было обследовано 9 из 27 человек – 34 (15-58)%. 18 пациентов было обследовано методом NGS, что составляет 67(42-85)%. У 2 родственных пациентов, у которых был выявлен только один вариант измененной последовательности гена DYSF, для поиска крупных делеций и (или) дупликаций была проведена мультиплексная лигаза-зависимая амплификация (MLPA). Выявленные методом NGS генетические варианты верифицировались референтным методом – ПЦР. Гистологическое и иммуногистологическое исследование выполнено четырем пациентам с неоднозначным результатом молекулярно-генетической диагностики. В качестве биоптата забран фрагмент (5 мм3 ) латеральной головки четырехглавой мышцы бедра. Результаты и выводы. Методом NGS в гене DYSF был выявлен 21 различный генетический вариант у 27 пациентов. 16 из 21 генетических вариантов ранее описаны; в четверти случаев (5 вариантов, 25(0-52)%) генетические варианты являются ранее не описанными (novel). Из 21 выявленного варианта на основании критериев ACMG 12 (57(31-81)%) были классифицированы как патогенные, 5 (25(0-51)%) – как вероятно патогенные, 4 (20(0-46)%) – как варианты с неизвестной клинической значимостью. Background. According to the frequency of occurrences dysferlinopathy occupies the second place in world among limb–girdle muscular dystrophy (LGMD) after calpainopathy. The disease has a relatively late manifestation and the similar clinical picture with other LGMD. In some cases, that creates significant difficulties in differential diagnostics. New generation sequencing (NGS) is method that quickly and efficiently allows to determine the variant of the DYSF gene that leads to violation of protein synthesis. Aim: to determine the effectiveness of identifying variants of nucleotide sequences in the DYSF gene by the NGS in patients with a clinical diagnosis of diferlinopathy and also to evaluate the possibilities of this method in differential diagnostics of LGMD. Methods. The search for genetic variants of the DYSF gene was performed in patients with detected phenotype of LGMD, as well as 10 to 100 times higher levels of creatine kinase (CK) and manifestation at the age of 2-73 years. In total, 157 patients with a clinical signs of LGMD were included in the study. Changes in the sequence of the DYSF gene were detected in 27 of them. 9 of 27 people – 34(15-58)% were examined with Sanger sequencing. 18 of them – 67(42-85)% were examined by the NGS method. In two patients only one changed variant in the DYSF gene was detected, in this regard multiplex ligation-dependent probe amplification (MLPA) was performed to search for large deletions and (or) duplications. The identified genetic variants were verified by the reference method – PCR. Histological and immunohistological examination was performed in four patients with ambiguous results. As a biopsy material for examination were used fragments (5 mm3 ) of the lateral head of the quadriceps femoral muscle. Results and conclusions. Using the NGS method, in 27 patients 21 genetic variant of the DYSF gene was identified. 16 variants out of 21 belong to the category of previously described; thus, in almost a quarter of cases (5) – 25(0-52)% variants weren’t described before (novel). Among the 21 identified variants, based on ACMG criteria, 12 – 57(31-81)% variants were classified as pathogenic, 5 – 25(0-51)% as probably pathogenic and 4 – 20(0-46)% as variants with uncertain significance, however, all detected variants were accompanied by a detailed clinical signs of LGMD.

We studied the effects of a dual-vector DYSF gene delivery system based on adeno-associated virus serotype 9 capsids on pathological manifestations of dysferlinopathy in skeletal muscles of Bla/J mice lacking DYSF expression. The mice received intravenous injection of 3×1013 genomic copies of the virus containing the dual-vector system. M. gastrocnemius, m. psoas major, m. vastus lateralis, and m. gluteus superficialis were isolated for histological examination in 3, 6, and 12 weeks after treatment. Healthy wild-type (C57BL/6) mice served as positive control and were sacrificed 3 weeks after injection of 150 μl of 0.9% NaCl into the caudal vein. To detect dysferlin in muscle cryosections, immunohistochemical analysis with diagnostic antibodies was performed; paraffin sections were stained with hematoxylin and eosin for morphometric analysis. After administration of gene-therapeutic constructs, muscle fibers with membrane or cytoplasmic dysferlin location were detected in all examined muscles. The proportion of necrotic muscle fibers decreased, the number of muscle fibers with central location of the nucleus increased, and the mean cross-section area of the muscle fibers decreased.

Введение. Тяжелые побочные явления лекарственных средств и возникающая фармакологическая резистентность к базисной противоревматической терапии у пациентов с ревматоидным артритом (РА) способствуют поиску новых методов лечения. Одним из перспективных направлений современной эфферентной терапии являются методики экстракорпоральной гемокоррекции, селективно воздействующие на патологические механизмы систем иммунитета и гомеостаза., в частности метод экстракорпорального фотофереза (ЭКФ), основанный на селективной экстракорпоральной фотохимической обработке мононуклеарных клеток периферической крови. В статье изложены результаты и обсуждается влияние комплексной адаптивной иммунотерапии на субпопуляционный состав лимфоцитов и Т-регуляторные клетки у пациентов с РА. Цель исследования - изучение особенностей Т-клеточного иммунитета у больных ревматоидным артритом на фоне комплексной адаптивной иммунотерапии. Методика. Обследовано 100 пациентов с верифицированным диагнозом РА, согласно критериям Американской коллегии ревматологов / Европейской антиревматической лиги (ACR/EULAR, 2010). Всех пациентов разделили на основную и контрольную группу. В основную были включены 50 пациентов, получающих базисные противоспалительные препараты в сочетании с ЭКФ в программном режиме (две процедуры в 2,5-3 мес в течение 24 мес), в контрольную группу вошли 50 пациентов, получающих только стандартную базисную монотерапию. Результаты. Установлено, что применение ЭКФ снижает функциональную активность NK-клеток и Т-лимфоцитов, экспрессирующих α-цепь рецептора ИЛ-2, за счет увеличения в периферической крови уровня Т-регуляторных клеток у большинства исследуемых пациентов с РА. Заключение. Включение ЭКФ, как компонента комплексной противоревматической терапии у пациентов с РА, усиливает иммуномодуляторный эффект за счет увеличения в периферической крови уровня Т-регуляторных клеток и снижения функциональной активности Т-активированных лимфоцитов, что в свою очередь восстанавливает дисбаланс в Т-клеточной популяции и сохраняет периферическую иммунотолерантность к собственным антигенам. Introduction. Severe side effects of drugs and emerging pharmacological resistance to basic antirheumatic therapy in patients with rheumatoid arthritis (RA) warrant the search for new methods of treatment based on selective extracorporeal photochemical processing of peripheral blood mononuclear cells. This article presents the results and discusses the impact of complex adaptive immunotherapy on the subpopulation composition of lymphocytes and T-regulatory cells in patients with RA. The aim was to study the properties of T-cell immunity in patients with RA during complex adaptive immunotherapy. Methods. We examined 100 patients with a verified diagnosis of RA, according to the criteria of the American College of Rheumatology/European Antirheumatic League (ACR/EULAR, 2010). The patients were divided into a main and a control group. The main group included 50 patients that received basic anti-inflammatory drugs in combination with extracorporeal photopheresis (ECP) in a program mode (two procedures every 2.5-3 mos. for 24 mos.). The control group included 50 patients that received only standard, basic monotherapy. Results. ECP reduced the functional activity of NK cells and T-lymphocytes that expressed the α-chain of the IL-2 receptor due to an increase in T-regulatory cells in the peripheral blood in most treated patients with RA. Conclusion. The inclusion of ECP as a component of complex antirheumatic therapy in patients with RA enhances the immunomodulatory effect. This is due to an increase in the content of T-regulatory cells in the peripheral blood and a decrease in the functional activity of T-activated lymphocytes, which, in turn, restores the imbalance in the T-cell population and preserves the peripheral immunotolerance to self-antigens.

Anti-MuSK myasthenia is a chronic autoimmune disease caused by violation of the function of the agrin-MuSK-Lrp4 complex, accompanied by the development of pathological muscle fatigue and often muscle atrophy. The disease can be a primary, as well as a complication of immunosuppressive therapy and hematopoietic stem cell transplantation. We present a case of anti-MUSK myasthenia gravis that developed after allogeneic HSCT due to acute myeloid leukemia in a 44-year-old patient (born in 1975). A distinctive feature of the case was a generalized injury, including not only extraocular, but also paravertebral muscles, dropped head syndrome in the evening. In addition, laboratory, electroneuromyographic and neuroimaging (MRI of muscles, MR-spectroscopy) data indicating the neurogenic reversible nature of changes in the involved musculature are presented.Results. This study presents MRI and EMG signs of neurogenic damage of axial musculature in a patient with weakness and swelling of the paravertebral muscles (edematous changes according to STIR, corresponding to MR signs of early functional denervation) for a period of 2–4 months, due to anti-MUSK myasthenia gravis. Clinical manifestations, as well as edematous neurogenic changes in the paravertebral muscles, regressed after pathogenetic therapy. Conclusion. The article presents up-to-date data on the clinical and instrumental characteristics of myasthenia gravis. The considered clinical example confirms the presence of neurogenic changes at an early stage of anti-MUSK myasthenia gravis and indicates the need for immediate initiation of pathogenetic therapy to avoid the development of atrophy and fatty infiltration of muscles.

The aim of the work was behavioral and pathomorphological phenotyping of the mice knockout for the DYSF gene, which plays an important role in the development and progression of dysferlinopathy.Materials and methods. A B6.A-Dysfprmd/GeneJ (Bla/J) mice subline was used in the work. During the study, a muscle activity was determined basing on the following tests: “Inverted grid”, “Grip strength”, “Wire Hanging”, “Weight-loaded swimming”, Vertical Pole”. Histological and immunofluorescent examinations of skeletal muscles (m. gastrocnemius, m. tibialis) were performed. The presence and distribution of the dysferlin protein was assessed, and general histological changes in the skeletal muscle characteristics of mice at the age of 12 and 24 weeks, were described. A morphometric analysis with the determination of the following parameters was performed: the proportion of necrotic muscle fibers; the proportion of fibers with centrally located nuclei; the mean muscle fiber diameter.Results. The “Grip strength” test and the “Weight-loaded swimming” test revealed a decrease in the strength of the forelimbs and endurance in the studied mice of the Bla/J subline compared to the control line. The safety of physical performance was checked using the “Wire Hanging” test and the “Vertical Pole” test, which showed a statistically significant difference between the studied mice and control. The coordination of movements and muscle strength of the limbs examined in the “Inverted Grid” test did not change in these age marks. Decreased grip strength of the forelimbs, decreased physical endurance with age, reflects the progression of the underlying muscular disease. Histological methods in the skeletal muscles revealed signs of a myopathic damage pattern: necrotic muscle fibers, moderate lympho-macrophage infiltration, an increase in the proportion of fibers with centrally located nuclei, and an increase in the average fiber diameter compared to the control. The dysferlin protein was not found out in the muscle tissues.Conclusion. Taking into account the results of the tests performed, it was shown that the absence of Dysf-/- gene expressionin Bla/J subline mice led to muscular dystrophy with the onset of the development of phenotypic disease manifestations at the age of 12 weeks and their peak at 24 weeks. Histopathological phenotypic manifestations of the disease are generally nonspecific and corresponded to the data of intravital pathoanatomical examination in diferlinopathy patients. The mice of the studied subline Bla/J are a representative model of dysferlinopathy and can be used to evaluate new therapeutic agents for the treatment of this disease.

Calpainopathy is the most common form of limb-girdle muscular dystrophy, prevalence in the population is approximately 1 in 15,00042,700 individuals. In the Russian Federation, there is an insufficient number of studies, which researched prevalence of calpainopathy among patients with limb-girdle muscular dystrophy, but according to available data, approximately in 43% of cases the disease is associated with mutations of the CAPN3 gene. Molecular genetic analysis is the main method for diagnosing these patients. Studies indicate many pathogenic mutations that cause calpainopathy with corresponding phenotypes, however, it is quite difficult to establish clear correlations between genotype and phenotype due to the high variability of symptoms and severity, even among patients with the same CAPN3 gene mutations. Currently, there is no effective etiotropic treatment for limb-girdle muscular dystrophy, but new technologies are developing to improve patients condition and quality of life. This research collects data from various studies on the prevalence of calpainopathy in different countries and the main molecular genetic features of the CAPN3 gene and calpain-3 protein, which will further allow the development of possible treatment options for patients with limbgirdle muscular dystrophy.

Differential diagnosis of inflammatory myopathies with hereditary muscular dystrophies accompanied by a secondary inflammatory process is a time‑consuming clinical and pathomorphological task. In particular, false diagnosis of polymyositis in patients with dysferlinopathy reaches 25 % of cases.A 40‑year‑old female patient with a limb‑girdle phenotype of dysferlinopathy, initially diagnosed as polymyositis, is presented. The reasons that led to the erroneous diagnosis were: sporadic case; subacute onset; proximal muscle weakness; myalgia, which stopped on the glucocorticosteroid therapy; high levels of creatine phosphokinase (up to 17 times); the presence of lymphocytic‑macrophage infiltrate in the muscle biopsy and the absence of magnetic resonance imaging data in primary examination of the patient.The refractoriness of clinical and laboratory signs to complex immunosuppressive therapy was the reason for revising the muscle biopsy with typing of the inflammatory infiltrate. The predominantly unexpressed perivascular infiltrate was characterized by the predominance of macrophages and, to a lesser extent, CD4+, which indicated the secondary nature of the inflammation in the muscle observed in some hereditary muscular dystrophies. When conducting an immunohistochemical reaction, the absence of the dysferlin protein in the sarcoplasmic membrane was revealed.Whole‑exome sequencing (NGS) revealed a mutation in exon 39 of the DYSF gene (p.Gln1428Ter) in the heterozygous state, which leads to the appearance of a stop codon and premature termination of protein translation. MLPA method registered 3 copies of exons 18, 19, 20, 22, 24 of the DYSF gene.Thus, this clinical example reflects the main methodological errors and possible effects of immunosuppressive therapy in patients with dysferlinopathy.