Drug dosing remains one of the topical issues of modern pediatrics. Insufficient number of clinical studies, vulnerable patient populations (preterm newborns, patients with renal and/or hepatic insufficiency, obesity), and high risk of polypragmasy create additional difficulties for practicing physicians. This review provides description of currently used approaches to drugs dosing in children. It has been shown that prognostic models should be used for solving drugs dosing issues regarding characteristics of young patients. Such models include: physiologically based pharmacokinetic modelling; population pharmacokinetic analysis; model-based precision dosing; modeling and simulation approach; use of real world data; and pharmacogenetic testing-based dosing. These models use information from preclinical and clinical stu

This review provides data on the use of yogurts in infants’ nutrition. The properties of these fermented milk products and associated urgent and delayed sanogenetic effects are described. The experience of yogurts (enriched with pre- and probiotics) implementation in the nutrition therapy of children who have undergone infectious diseases is shown. The yogurt usage for intestinal microbiota disorders correction in children with functional digestive disorders and chronic somatic pathology is discussed.

Congenital aniridia manifests with total or partial absence of the iris. The association of the disease with the PAX6 gene has been proven. Changes in the PAX6 structure lead to intrauterine pathology, visual organ malformation, malformation of master regulator proteins of organogenesis affecting various cells’ differentiation (central nervous system cells included). Such disorders result into the development of PAX6-associated syndromes with various brain malformations, neurological disorders, and systemic pathology (thyroid pathology, Wilms tumor, glucose intolerance). Isolated congenital aniridia is also accompanied by psychoneurological disorders. It can be associated with brain structures’ disorders during embryogenesis and with impact of external stress factors on the child (frequent medical checkup, surgical treatments). The psychoneurological disorders’ pathogenesis as well as congenital aniridia’s genetic mechanisms remain unclear. Thus, it is crucial to review new relevant data within the context of previously obtained information to gather full picture of the clinical signs of the disease and to improve the management of children with congenital aniridia.

Background. Congenital central hypoventilation syndrome (CCHS), or Ondine’s Curse, is rare, incurable and life-threatening disease characterized by autonomic nervous system disorders, it manifests with disability to maintain ventilation function during sleep. Sensitivity to hypoxia and hypercapnia is reduced in case of CCHS, thus, it leads to recurrent episodes of deep apnea. The world literature describes just over 1000 cases of this disease. Clinical case description. An infant born at 37th week of gestation, weight of 3330 g, had episodes of apnea and hypercapnia from the first day of life. CCHS was suspected by the 28th day of life after excluding other causes of respiratory disorders, and it was genetically confirmed by the 43rd day of life — pathogenic variant of PHOX2B gene was revealed. Mechanical ventilation has been initiated by the age of 1 month after disease worsening. Analysis of CCHS cases published in Russian-language medical literature was performed. Typical symptoms and timing of their manifestation, as well as the time before correct diagnosis were mentioned. Conclusion. Symptoms that can be suggestive of CCHS presence early after birth and can urge to perform all the necessary genetic testing that are crucial for timely treatment onset and for minimizing the negative effect of hypoxemia and hypercapnia on the child are described.

Background. Abnormal uterine bleeding (AUB) in adolescence is one of the urgent problems of medicine nowadays. It is on the 2nd place among all the reasons for hospitalization in gynecological departments, and its incidence among girls during puberty is 50%. Clinical case description. This is the clinical case of 15-year-old girl admitted to the gynecology department with complaints   on long-lasting bloody vaginal discharge, fatigue, dizziness. The diagnosis of «abnormal uterine bleeding in adolescence» burdened with iron deficiency anemia (IDA) was established according to laboratory and instrumental examinations. The patient underwent RBC-transfusion with specific buffy coat and was administered with hormonal hemostatic and anti-anemic therapy. Conclusion. We can conclude (with reference to this observation and the reviewed literature) not only that IDA is one of the most common complications of AUB in adolescence, but also what management should be used in such clinical cases.

Background. Mucopolysaccharidosis type II (MPS II, Hunter syndrome) is an X-linked recessive disease caused by lysosomal enzyme iduronate-2-sulfatase deficiency resulting in progressive glycosaminoglycans (GAG) accumulation in tissues (dermatan sulfate and heparan sulfate). GAG accumulation in cells leads to the development of progressive pathological disorders, malfunction of various organs and systems, early disability, and decrease in life expectancy. Enzyme replacement therapy (ERT) reduces the rate of life-threatening conditions development in patient. ERT would be more effective if it is prescribed early, especially at preclinical stage. This is the time when there are no severe irreversible changes in the cell, thus, pathogenetic therapy will decrease GAG accumulation in lysosomes, slow down the pathological process, and improve patient's condition. Clinical case description. Male patient diagnosed with MPS II was administrated with ERT idursulfase beta at the age of 6 months. It led to milder disease course compared to proband uncle who had similar mutation in the IDS gene, severe disease phenotype, and later initiation of ERT (at the age of 2.5 years). Conclusion. Early ERT initiation in patients with MPS II significantly slows down development of severe and life-threatening complications, increases the duration and improves the quality of life.

Background. Hereditary polyposis syndromes (HPS) are a group of rare genetic diseases characterized by multiple epithelial lesions in the gastrointestinal tract (GIT) with high risk of malignancy and neoplasia development in other localizations. The case follow-up tactics in hereditary polyposes have significant differences, and differential diagnosis can be complicated due to the phenotype variability and the clinical manifestations similarity. Objective. The aim of the study is to determine the role of molecular genetic testing and endoscopic examination in the diagnosis and management of children with HPS. Materials and methods. The retrospective observational study included 17 patients with clinical signs of hereditary polyposes who applied to the L.A. Durnov Research Institute of Pediatric Oncology and Hematology during the period from 2013 to 2023. All patients underwent molecular genetic testing and comprehensive endoscopic examination of upper and lower GIT. Results. We have divided patients into 7 groups according to the results of genetic testing. Patients had various mutations in genes associated with hereditary tumor syndromes: STK11 (35.3%; n = 6), APC (17.6%; n = 3), PTEN (11.8%; n = 2), SMAD4 (5.9%; n = 1), BMPR1A (5.9%; n = 1), MUTYH (5.9%; n = 1), MLH1 (5.9%; n = 1). One female patient with colorectal cancer with history of adenomatous polyp had pathogenic variants in the ATM and CHEK2 genes; it could be considered as multi-locus tumor syndrome (MINAS) (5.9%, n = 1). Another female patient (5.9%) had multiple gastric body hamartoma polyps and multiple gastric gastrointestinal stromal tumors (GIST) but with no pathogenic mutations. Complex endoscopic examination was performed in 14 (82.3%) patients. Epithelial or non-epithelial lesions of the stomach and intestine were revealed in all cases. Malignant tumors of duodenum and colon were diagnosed in 3 out of 14 patients (21.4%). Morphological variants of these GIT lesions were represented by hamartoma, hyperplastic, and juvenile polyps, adenomas, serrated adenomas, adenocarcinoma, and GIST. The diagnosed epithelial lesions of the stomach, duodenum, and colon were removed via endoscopic polypectomy and endoscopic mucosal resection in 8 out of 14 patients (57.1%). Some cases required small bowel resection (14.3%, n = 2), total colectomy (14.3%, n = 2), and gastrectomy (14.3%, n = 2). Conclusion. Understanding the molecular and biological etiology of HPS, its endoscopic diagnosis, and treatment features allows us to optimize the management of such patients and to minimize the risks of developing malignant tumors in upper and lower GIT, as well as extraintestinal tumors by carrying out timely medical and preventive measures.