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.
