title: Clinical and Genetic Characterization of Tunisian Children with Hereditary 1,25-Dihydroxyvitamin D-Resistant Rickets.
abstract: BACKGROUND
  Hereditary vitamin D-resistant rickets (HVDRR) is an autosomal recessive disorder characterized by the early onset of rickets and is caused by mutations in the vitamin D receptor (VDR) gene. Some HVDRR patients also have alopecia.
  
  
  METHODS
  We retrospectively studied the clinical features, laboratory findings, genetic defects, as well as responses to treatment in a series of children with HVDRR.
  
  
  RESULTS
  Eight patients from 7 families met the inclusion criteria. Alopecia was noted in 7 patients. Two different homozygous mutations in the VDR gene were identified in 6 patients: the p.K45E mutation located in the DNA-binding domain (5 patients with alopecia) and a novel p.T415R mutation located in the ligand-binding domain. A p.E143del CYP24A1 mutation, in the gene encoding the 25-hydroxyvitamin D3-24-hydroxylase, was identified in 2 brothers carrying the VDR gene mutation p.K45E. Six patients were treated with intermittent intravenous calcium treatment via the peripheral route with a clear improvement in 5 cases.
  
  
  CONCLUSIONS
  To the best of our knowledge, this is the first major series reporting on HVDRR in Tunisia. The same mutation (p.K45E) was found in 5 apparently unrelated affected individuals. We have also extended the mutation spectrum by studying 1 novel VDR mutation.
authors.affiliation: Pediatric Department, Hedi Chaker Hospital, Sfax, Tunisia.
authors.forename: Salma
authors.initials: S
authors.lastname: Ben Ameur
authors.forename: Caroline
authors.initials: C
authors.lastname: Silve
authors.forename: Imene
authors.initials: I
authors.lastname: Chabchoub
authors.forename: Fatma
authors.initials: F
authors.lastname: Damak
authors.forename: Fatma
authors.initials: F
authors.lastname: Kamoun
authors.forename: Aurélie
authors.initials: A
authors.lastname: Toussaint
authors.forename: Sana
authors.initials: S
authors.lastname: Kmiha
authors.forename: Lamia
authors.initials: L
authors.lastname: Sfaihi
authors.forename: Ines
authors.initials: I
authors.lastname: Maaloul
authors.forename: Thouraya
authors.initials: T
authors.lastname: Kamoun
authors.forename: Hajer
authors.initials: H
authors.lastname: Aloulou
authors.forename: Mongia
authors.initials: M
authors.lastname: Hachicha
mesh_terms: D019943:Amino Acid Substitution; D002675:Child, Preschool; D053098:Familial Hypophosphatemic Rickets / Q000097:blood / Q000235:genetics; D005260:Female; D006801:Humans; D007223:Infant; D008297:Male; D020125:Mutation, Missense; D018167:Receptors, Calcitriol / Q000235:genetics*; D014416:Tunisia
chemical_list: D018167:Receptors, Calcitriol