ABSTRACT Objective: The aim of this cross-sectional study was to estimate the prevalence of XLH in Paraná, a state in southern Brazil, and report the clinical features and complications of the disease. Materials and methods: We invited all endocrinologists (n = 205), nephrologists (n = 221), orthopedic surgeons (n = 1020), and pediatricians (n = 1000) in Paraná to fill out an electronic survey with information on patients with X-linked hypophosphatemia (XLH), and searched the records of the state's health department for all calcitriol prescriptions in 2018. Results: In all, 244 (10%) specialists responded to the email, of whom 18 (7.4%) reported to be taking care of patients with XLH and answered the online survey. A total of 57 patients with XLH were identified (prevalence 5 per million inhabitants). The median age at diagnosis was 22 years, and 42.2% were children and adolescents. Fifteen patients had genetic testing showing a PHEX mutation. Overall, 91.2% had bone deformities, 30.8% had a history of fragility fractures, and 22.4% had renal complications. Conclusion: This study demonstrated a prevalence of XLH of 5 cases per million inhabitants in the state of Paraná, a rate lower than the one reported in other countries. Manifestations of renal calcification and bone fragility were frequent among the patients. This is the first epidemiological study evaluating the prevalence and clinical presentation of XLH in Latin America.

RESUMO Introdução: A vitamina D é considerada um pré-hormônio e apresenta papel crucial na homeostase do cálcio e, consequentemente, na saúde óssea. A maior fonte de vitamina D é a pele, em resposta à luz solar. Apenas pequenas quantidades dessa vitamina são encontradas em alguns alimentos (especialmente peixes gordurosos), o que faz com que a disponibilidade da vitamina D na dieta seja limitada. Estudos populacionais brasileiros demonstram que a prevalência da hipovitaminose D no nosso país é elevada. Objetivo: Definição dos intervalos de referência para vitamina D [25(OH)D]. Discussão: Consenso de especialistas - revisão da literatura. Conclusão: A padronização dos intervalos de referência é fundamental para o correto diagnóstico e tratamento da hipovitaminose D.

ABSTRACT Introduction: Vitamin D is considered a pre-hormone and plays a crucial role in calcium homeostasis and, consequently, in bone health. The best source of vitamin D is the skin in response to sunlight. Only small amounts of this vitamin are found in some foods (especially fatty fish), which makes availability of vitamin D in the diet limited. Brazilian population studies show that the prevalence of hypovitaminosis D in our country is high. Objective: To define the reference intervals for vitamin D [25(OH)D]. Discussion: Consensus of specialists - literature review. Conclusion: The standardization of reference intervals is fundamental for the correct diagnosis and treatment of hypovitaminosis D.

Descrevemos quatro casos de fraturas femorais atípicas atendidos no Serviço de Endocrinologia do Hospital de Clínicas da Universidade Federal do Paraná (SEMPR/UFPR) que, apesar de característicos desse tipo de fratura, apresentam peculiaridades clínicas que devem ser consideradas e servir de alerta nesses pacientes, tais como: diagnóstico tardio com manutenção do uso de bisfosfonatos; ausência de comorbidades associadas com resolução sem sequelas; falha na consolidação da fratura; uso de medicação anabólica após a fratura e acompanhamento com marcadores de remodelação óssea.

We describe four cases of atypical femoral fractures treated at the Department of Endocrinology, Hospital de Clínicas, Federal University of Paraná (SEMPR) which, although characteristic of this type of fracture, presented clinical peculiarities that should be considered and serve as a warning in these patients, such as: late diagnosis with maintenance of bisphosphonates; absence of co-morbidities with excellent result; failure of fracture healing; use of anabolic medication after the fracture and the use of bone turnover markers at the follow up.