In the cohort of Russian patients with cystic fibrosis, the p.[Leu467Phe;Phe508del] complex allele (legacy name [L467F;F508del]) of the CFTR gene is understudied. In this research, we present the results of frequency evaluation of the [L467F;F508del] complex allele in the Russian Federation among patients with a F508del/F508del genotype, its effect on the clinical course of cystic fibrosis, the intestinal epithelium ionic channel function, and the effectiveness of target therapy. The frequency of the [L467F;F508del] complex allele among patients with homozygous F508del was determined with multiplex ligase-dependent probe amplification followed by polymerase chain reaction and fragment analysis. The function of ionic channels, including the residual CFTR function, and the effectiveness of CFTR modulators was analyzed using intestinal current measurements on rectal biopsy samples and the forskolin-induced swelling assay on organoids. The results showed that the F508del/[L467F;F508del] genotype is present in 8.2% of all Russian patients with F508del in a homozygous state. The clinical course of the disease in patients with the F508del/[L467F;F508del] genotype is severe and does not vary from the course in the cohort with homozygous F508del, although the CFTR channel function is significantly lower. For patients with the F508del/[L467F;F508del] genotype, we can recommend targeted therapy using a combined ivacaftor + tezacaftor + elexacaftor medication.

A registry of patients with cystic fibrosis (CF) of the Russian Federation has been compiled annually since 2011. Analysis of the national registry with large amounts of clinical and laboratory data helps understand changes in demographic indicators, plan measures to improve the quality of medical care and evaluate their effectiveness.Aim. To analyze health status of patients with cystic fibrosis in the Russian Federation and the dynamics of key clinical and laboratory parameters from 2011 to 2021. Methods. The health status of CF patients was assessed using the registry data from 2011 to 2021.Results. The analysis revealed an increase in the total number of patients from 1,026% in 2011 to 3,969 in 2021, in the number of patients identified by neonatal screening from 28.8% to 53.5%, and in coverage by genetic testing from 91.8 to 93.6%. At the same time, the number of mutations detected dropped from 80 to 90.5% and the number of patients with unidentified mutations decreased from 9.5 to 3.2%. The mean age at diagnosis of cystic fibrosis did not change (3.3 ± 5.5 in 2011 and 3.1 ± 6.2 in 2021) despite an increase in the number of patients diagnosed through neonatal screening. There was a difference in M ± SD age from 2011 to 2021 (11.5 ± 8.9 in 2011 and 14 ± 9.8 in 2021). The proportion of adult patients was 24.95% in 2011 and 27.4% in 2021. The therapy changed over 11 years - the number of courses of intravenous therapy decreased from 70.9 to 36.4%, the number of patients using inhaled antipseudomonal therapy expanded to 45%, the number of patients using hypertonic sodium chloride solution expanded from 8.7 to 70.7%, the use of glucocorticoids decreased. The targeted therapy was introduced in 2018, and the number of patients receiving pathogenetic drugs is growing.Conclusion. The observed changes are indicative of the health status of Russian patients with cystic fibrosis. Analysis of registries helps improve the organization of medical care, predict and implement sanitary and epidemic measures, plan therapy, and assist the regions in organizing outpatient monitoring and microbiological control. The registry is analyzed to organize health care for adult patients.

Primary ciliary dyskinesia (PCD) (Online Mendelian Inheritance in Man - OMIM - #242650) is a rare hereditary disease, which is based on a defect in the ultrastructure of the cilia epithelium of the respiratory tract which leads to the motor function disorder. Data about health characteristics of patients with PCD in the Russian Federation are incomplete.The aim of the study was to investigate the clinical, laboratory, and instrumental characteristics of patients with PCD.Methods. The data of 90 patients (22 adults (24.4%) and 68 children (75.6%)) from several medical centers were studied. The following methods were used: medical history, spirometry, microbiological examination of the respiratory tract, video microscopic analysis of the functional activity of the nasal mucosa ciliated epithelium, transmission electron microscopy of the ciliated epithelium, and DNA testing.Results. The median age at diagnosis was 17.0 years for adults and 5.0 years for children. Kartagener syndrome was detected in 23 (27%) people, including 6 (26.0%) adults. Hearing loss was noted in 5 (26.3%) adult patients and 15 (26.8%) children. Light microscopy of the ciliated epithelium was performed in 14 (82.3%) children and 3 (17.7%) adults. In 12 patients, cilia motor activity was not registered at each of the magnifications (x 100, x 400, x 1,000). Transmission electron microscopy showed that absence ofinternal and external dynein handles (51%) and absence of internal dynein handles (17.9%) were the most common disorders. DNA testing was performed in 55 (61.2%) patients: 16 (29.1%) adults and 38 (70.9%) children. The most common genetic variants were found in the DNAH5 and HYDIN genes. Lung function was reduced in both adults and children, but a significant decrease was noted in adult patients. P. aeruginosa predominated in the culture and accounted for 21.3% (intermittent detection in 13.2%, persistent detection in 9%). It has increased resistance to antibiotics.Conclusion. The results correlate with the European data. Infection caused by P. aeruginosa with the increased resistance to antibiotics was prevalent in patienths with PCD.

The pathogenic variant E92K (c.274G > A) of the CFTR gene is rare in America and Europe, but it is common for people with cystic fibrosis from Russia and Turkey. We studied the effect of the E92K genetic variant on the CFTR function. The function of the CFTR channel was studied using the intestinal current measurements (ICM) method. The effects of CFTR modulators on the restoration of the CFTR function were studied in the model of intestinal organoids. To assess the effect of E92K on pre-mRNA splicing, the RT-PCR products obtained from patients’ intestinal organoid cultures were analyzed. Patients with the genetic variant E92K are characterized by an older age of diagnosis compared to homozygotes F508del and a high frequency of pancreatic sufficiency. The results of the sweat test and the ICM method showed partial preservation of the function of the CFTR channel. Functional analysis of CFTR gene expression revealed a weak effect of the E92K variant on mRNA-CFTR splicing. Lumacaftor (VX-809) has been shown to restore CFTR function in an intestinal organoid model, which allows us to consider the E92K variant as a promising target for therapy with CFTR correctors.

Primary ciliary dyskinesia (PCD) is a rare hereditary disease, a ciliopathy that is based on a defect in the ultrastructure of the cilia of the epithelium of the respiratory tract and similar structures. All parts of the respiratory tract are affected. About half of the patients with PCD have transposition of the internal organs (Kartagener syndrome – KS).The aim was to investigate the clinical and genetic characteristics of patients with PCD with and without KS.Methods. An assessment of clinical and genetic characteristics was performed in a sample of 127 patients with PCD, who were divided into 2 groups: patients with KS (n = 60) and without KS (n = 67). The groups were compared on the basis of their medical history (according to the PICADAR scale), clinical, instrumental and laboratory data, including the results of light and video microscopy, transmission electron microscopy (TEM) and genetic testing.Results. According to the results of comparative characterization of patients with PCD with and without KS, there were similarities in the medical history, decreased lung function indices, videomicroscopy results – ciliated epithelium beating below 6 Hz, TEM – predominance of dynein arm defect. The PICADAR score was higher in the group with KS than in the group without it; congenital heart defects and renal pathology were found more frequently in patients with KS, while hearing loss and nasal polyposis were found more frequently in patients without KS. Electron microscopy revealed defects in the outer and inner dynein arms of the cilia in 50% of patients in both groups, and a tendency to lack of the central pair of microtubules in 18% of patients without KS. The following genes responsible for PCD were found in both groups: DNAH5, CFAP300 and HYDIN. DNAH5 gene variants were more common for KS patients (61.1%), while HYDIN gene variants were only found in patients with PCD without KS (15.8%).Conclusion. The identified differences may help in the diagnosis of the groups studied.

BACKGROUND: In recent decades, the life expectancy of patients with CF has increased, which leads to an increase in the frequency of conditions associated with impaired carbohydrate metabolism.AIM: to analyze the impact of cystic fibrosis-associated diabetes mellitus (CFDM) in children and adolescents on the course of cystic fibrosis according to the 2021 register of patients with cystic fibrosis of the Russian Federation (RF).MATERIALS AND METHODS: the data of the register of patients with cystic fibrosis of the Russian Federation for 2021 were analyzed. The study included 122 patients with diabetes mellitus requiring the use of insulin — 33 children (27%) and 89 adults (73%), the average age of children was 13.5±4.1, the average age of adult.patients aged 18 years and older was 27.4±6.6. To compare the course of cystic fibrosis in patients with and without diabetes mellitus, groups were formed that were comparable in age, gender, genotype — the group of patients without diabetes included 827 patients, 33 patients made up the group of patients with CFRD using insulin. Diagnostic criteria, indicators of respiratory function, microbiological status, nature of complications, volume of therapy were compared.RESULTS: Patients with CFRD have a lower FEV1 compared to children without diabetes mellitus — M±SD FEV1 (%) 85.2±27.5 in the group of patients without diabetes mellitus and M±SD FEV1 (%) 72.4±26.0 in patients with diabetes mellitus (p < 0.016), compared in the microbiological seeding groups — a trend towards more frequent chronic growth of Pseudomonas aeruginosa 54.50% versus 39.4% in the group without CFRD. An increase in MRSA was also more often detected — 9.1% compared with the group of children without diabetes — 3.1%. Antibacterial therapy is more commonly used — inhaled in 54.6% of patients without diabetes mellitus while children with CFRD received inhaled antibiotic therapy in 75.8% (p=0.017). There was a significant difference in the used antibacterial tablet therapy (p=0.013). A significant difference in the number of patients on oxygen therapy in the group with CFRD — 12.1%, versus 3.4% without CFRD (p=0.01) confirms a more severe course of cystic fibrosis in patients with CFRD.CONCLUSION: The prevalence of CFDM with the need for insulin therapy among children in the Russian Federation is 1.3%. Cystic fibrosis-associated diabetes mellitus significantly worsens the course of cystic fibrosis in terms of lung function, the growth of gram-negative and resistant flora, the presence of severe complications and the frequent use of antibiotic therapy, which is obviously associated with frequent exacerbations of the bronchopulmonary process in cystic fibrosis in patients with developed cystic fibrosis-associated diabetes mellitus.