title: Vitamin D dependent rickets, diagnostic and therapeutic difficulties: two case reports.
abstract: There are two types of vitamin D dependent rickets (VDDR) that cause rickets in children. Vitamin D dependent rickets type 1 (VDDR-I) is caused by an inborn error of vitamin D metabolism, which interferes with renal conversion of calcidiol (25OHD) to calcitriol (1,25(OH)2D) by the enzyme 1alpha-hydroxylase. Vitamin D dependent rickets type 2 (VDDR-II) is caused by a defect in the vitamin D receptor (VDR). We report cases of two African children affected by VDDR-I and VDDR-II, respectively. Establishing an early diagnosis of these genetic forms of rickets is challenging, especially in developing countries where nutritional rickets (NR) is the most common variety of the disease. A prompt diagnosis is necessary to initiate adequate treatment, resolve biochemical features and prevent complications, such as severe deformities that may require surgical intervention.
authors.affiliation: Department of Pediatrics, Vita-Salute San Raffaele University, San Raffaele Scientific Institute, via Olgettina 60, 20132 Milan, Italy.
authors.forename: Valentina
authors.initials: V
authors.lastname: Donghi
authors.forename: Marianna
authors.initials: M
authors.lastname: Di Frenna
authors.forename: Alessandra
authors.initials: A
authors.lastname: di Lascio
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Chiumello
authors.forename: Giovanna
authors.initials: G
authors.lastname: Weber
mesh_terms: D015090:25-Hydroxyvitamin D3 1-alpha-Hydroxylase / Q000235:genetics*; D055726:Cabo Verde; D002112:Calcifediol / Q000627:therapeutic use*; D002648:Child; D003937:Diagnosis, Differential; D003951:Diagnostic Errors; D042241:Early Diagnosis; D004534:Egypt; D005260:Female; D006801:Humans; D007223:Infant; D018167:Receptors, Calcitriol / Q000235:genetics*; D012279:Rickets / Q000175:diagnosis / Q000188:drug therapy / Q000235:genetics; D014815:Vitamins / Q000627:therapeutic use
chemical_list: D018167:Receptors, Calcitriol; D014815:Vitamins; D015090:25-Hydroxyvitamin D3 1-alpha-Hydroxylase; D002112:Calcifediol