Browsing by Author "Radlovic, Vladimir"

Mitochondrial encephalomyopathies (MEMP) are heterogeneous multisystem disorders frequently associated with mitochondrial DNA (mtDNA) mutations. Clinical presentation varies considerably in age of onset, course, and severity up to death in early childhood. In this study, we performed molecular genetic analysis for mtDNA pathogenic mutation detection in Serbian children, preliminary diagnosed clinically, biochemically and by brain imaging for mitochondrial encephalomyopathies disorders. Sanger sequencing analysis in three Serbian probands revealed two known pathogenic mutations. Two probands had a heteroplasmic point mutation m.3243A>G in the gene, which confirmed mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke-like episode syndrome (MELAS), while a single case clinically manifested for Leigh syndrome had an almost homoplasmic (close to 100%) m.8993T>G mutation in the gene. After full mtDNA MITOMASTER analysis and PhyloTree build 17, we report MELAS' association with haplogroups U and H (U2e and H15 subclades); likewise, the mtDNA-associated Leigh syndrome proband shows a preference for haplogroup H (H34 subclade). Based on clinical-genetic correlation, we suggest that haplogroup H may contribute to the mitochondrial encephalomyopathies' phenotypic variability of the patients in our study. We conclude that genetic studies for the distinctive mitochondrial encephalomyopathies should be well-considered for realizing clinical severity and possible outcomes.

Background: The forearm is the most common fracture site in childhood, accounting for every fourth pediatric fracture. It is well described that vitamin D is involved in the regulation of bone mineralization and skeletal homeostasis by the regulation of calcium absorption. The aim of our study was to determine the influence of 25-hydroxyvitamin D levels on forearm fracture falls in a pediatric population, depending on level of energy impact. Additionally, we also aimed to evaluate the correlation between 25-hydroxyvitamin D levels and other tested risk factors for pediatric fractures. Methods: We evaluated 50 eligible children aged 3 to 12 years with a forearm fracture. According to energy impact, patients were grouped into low-energy fractures (LEF) and high-energy fractures (HEF) groups. The general characteristics of the patients included age, gender, sport participation, and fractured bone and its localization. We analyzed 25-hydroxyvitamin D, parathyroid hormone (PTH), calcium, magnesium, phosphate, C-reactive protein (CRP) levels, and body mass index (BMI). Results: There is a significant difference in the 25-hydroxyvitamin D levels distribution between LEF and HEF (p < 0.001) and PTH levels (p = 0.002). For magnesium levels, calcium levels, phosphate levels, and CRP levels, there were no significant differences in their frequency distribution. For the group of patients with LEF, there is a significantly positive correlation between 25-hydroxyvitamin D and calcium levels (p = 0.019) and a borderline significantly positive correlation between 25-hydroxyvitamin D and magnesium levels (p = 0.050). For the group of patients with HEF, there was only a significantly positive correlation between 25-hydroxyvitamin D and PTH levels (p < 0.001). Conclusions: Children with LEF were more frequently insufficient in 25-hydroxyvitamin D levels but had normal calcium levels, compared to the ones with HEF. These findings suggest that LEF and HEF in children might to a certain degree have different pathophysiological mechanisms.