RESUMO
INTRODUCTION: Primary osteoporosis during childhood and adolescence represents an uncommon condition, and secondary forms are more likely to manifest at this age due to chronic disease and adverse effects of medical treatment. CASE REPORT: The authors report the case of a young male patient with a history of multiple idiopathic non-vertebral fragility fractures in addition to a family history of maternal osteoporosis and fracture, in whom osteoporosis was confirmed according to 2013 International Society for Clinical Densitometry (ISCD) criteria. Bone markers indicated low bone formation marker osteocalcin. Genetic testing revealed homozygosity for Sp1 COL1A1 gene polymorphism in combination to Fok-I vitamin D receptor (VDR) heterozygous polymorphism, to contribute to low bone mass and increased fracture risk. Severe premenopausal osteoporosis was present in the patient's mother, who was also tested positive for both gene polymorphisms. CONCLUSION: This case report highlights the association between COL1A1 and VDR candidate gene polymorphisms and fragility fractures in a family. Individual genetic testing might be of clinical value in idiopathic osteoporosis in young patients, identifying subjects at increased fracture risk.
RESUMO
Most of the body iron is found within hemoglobin in red cells (the erythron), a smaller amount being distributed in other tissues such as muscles and in deposits. Iron homeostasis is a finely tuned process in which the most important regulators are probably the liver-derived hepcidin which blocks iron absorption and directs iron towards deposits and the recently discovered erythroblast-derived erythroferrone which inhibits hepcidin synthesis and therefore increases availability of iron for hemoglobin synthesis. Hepcidin secretion is increased by inflammatory cytokines and erythroferrone production increases when there is active, expanding erythropoiesis, for example after acute blood loss. We hypothesize that in pathological situations associated with erythroid precursor suppression (erythroblastopenia), anemia is the result of two major mechanisms: (1) direct erythroblast suppression leading to decreased production of red cells and (2) low iron availability due to high hepcidin levels arising as a result of low erythroferrone production. Additionally, infectious episodes and other inflammatory conditions that often complicate the course of these diseases may further promote hepcidin synthesis through increased cytokine production leading to even lower iron availability and a vicious circle of worsening anemia.
