Osteogenesis imperfecta type VI is a rare autosomal recessive disorder characterized by bone fragility and defective mineralization, caused by pathogenic variants in the SERPINF1 gene. This study aimed to expand the understanding of OI type VI by analyzing clinical, radiological, and molecular findings in four patients from three unrelated families. Genotyping revealed two novel SERPINF1 variants, c.185G>T (p.Gly62Val) and c.992_993insCA (p.Glu331Asnfs), in a compound heterozygous state in one patient, and a known pathogenic variant, c.261_265dup (p.Leu89Argfs26), in a homozygous form in three patients. Clinical manifestations included early-onset fractures, severe skeletal deformities, impaired mobility, and growth failure. Radiological assessments revealed multilevel and multiplanar bone deformities and metaphyseal widening. RNA analysis demonstrated that the c.992_993insCA variant results in a truncated PEDF protein without triggering nonsense-mediated decay. Population screening identified a carrier frequency of 0.0044 for the c.261_265dup variant, suggesting a founder effect in the Tuvinian population. These findings expand the mutational spectrum of the SERPINF1 gene and provide new insights into the phenotypic variability of OI type VI. Our results highlight the importance of genetic screening in isolated populations and emphasize the need for further research to develop more effective therapeutic approaches for patients with limited response to bisphosphonate therapy.

Косолапость является наиболее часто встречающейся деформацией при артрогрипозе и характеризуется высокой степенью ригидности и склонностью к рецидивам. В настоящее время единого мнения по вопросу лечения данной патологии не существует. Цель исследования - показать возможности применения метода Понсети при лечении косолапости у детей младшего возраста с артрогрипозом. Материал и методы. Работа основана на анализе результатов лечения 64 детей (124 стопы) в возрасте до 3 лет. У 50 пациентов (78%) был врожденный множественный артрогрипоз, 14 детей (22%) имели дистальную форму заболевания. Все дети получали консервативное лечение с применением метода Понсети. Результаты. У детей с врожденным множественным артрогрипозом в возрасте до 1 года коррекция компонентов деформации в результате этапного гипсования с применением метода Понсети получена на 25 (48%) стопах, у детей в возрасте от 1 года до 3 лет - на 4 (8,7%) стопах. У детей в возрасте до года с дистальной формой заболевания этапное гипсование позволило добиться коррекции на всех 7 (100%) стопах. У пациентов с той же формой заболевания в возрасте от 1 до 3 лет коррекция получена на 3 (23%) стопах. В случае неполной коррекции элементов деформации, когда возможности этапного гипсования были исчерпаны, выполнялись различные хирургические вмешательства, однако проведения операции по удалению таранной кости не потребовалось ни в одном случае. Выводы. Метод Понсети наиболее эффективен при лечении косолапости у детей первого года жизни. Применение метода позволяет устранить косолапость или значительно снизить объем последующего хирургического лечения.

BACKGROUND: Bruck syndrome is a rare disorder that features osteogenesis imperfecta, combined with severe congenital joint contractures often with pterygia, short stature, severe limb deformities, and progressive scoliosis. Its two forms, Bruck syndrome types 1 and 2, have similar clinical manifestations without osomal recessive inheritance and are caused by pathogenic variants of the nucleotide sequences in the FKBP10 and PLOD2 genes, respectively. CLINICAL CASES: The article demonstrates phenotypic and radiographic features as well as laboratory values of siblings with Bruck syndrome type 2 (a 10-year-old boy and a 13-year-old girl) born to healthy parents in a consanguineous marriage. The boy had congenital flexion contractures of the knee and elbow joints, few fractures, and severe kyphoscoliosis. The girl had no congenital joint contractures but had kyphoscoliosis, more severe osteoporosis, and a history of having more fractures than her younger brother. DISCUSSION: The cases demonstrated the significant phenotypic intrafamilial variability of Bruck syndrome type 2, caused by a newly identified homozygous variant c.1885AG (p.Thr629Ala) in PLOD2, which consists of varying degrees of osteoporosis, and the presence and severity of contractures. CONCLUSIONS: The description of the given clinical observation was made to draw attention to a rare pathology and expand doctors’ knowledge about the variability of clinical manifestations of Bruck syndrome. Genetic diagnostics is necessary for the timely diagnosis of Bruck syndrome, determining the prognosis and developing patient management techniques.

BACKGROUND:Ahuman tail isarare congenital malformation that corresponds to the protrusion on the dorsal side of the lumbar, sacrococcygeal, and paraanal regions. This study aimed to demonstrate three rare clinical cases ofatail-shaped formation caused by the protrusion ofanelongated coccyx in children. CLINICAL CASES:These patients asked for medical assistance for pain felt in the sitting position and daily discomfort because this formation barely contains any tissues other than the coccyx. The patients had no signs of neurological and lower urinary tract insufficiency. In all cases, the retroposition of the coccyx without its typical anterior angulation was determined based on radiographic and magnetic resonance imaging (MRI) signs. In one case, the coccyx was represented by four elongated vertebrae withoutatypical decrease in the size of the vertebrae in the caudal direction. In two cases,anangular deformity of the coccyx occurred at the level of CoIIIwith intercoccygeal angles of 138 and 140. DISCUSSION:The tail-like formations could be classified as pseudo-tails according to the classification by Dao and Netsky (1984) and type Ia human tails according to the classification by Tojima and Yamada (2020). CONCLUSIONS:The most important feature of tail-shaped formation is the connection with occult dysraphic malformations, which requiresacomprehensive preoperative examination in each case (neurological examination, radiography, computed tomography, and MRI). Careless surgery may lead to serious consequences that significantly impair patients quality of life.