title: Evidence of a marked 25-hydroxyvitamin D deficiency in patients with congenital ichthyosis.
abstract: BACKGROUND
  Vitamin D is essential for bone mineralization, and its deficiency may be the cause of skeletal fractures and osteomalacia. Geographical or ethnic factors may modulate the cutaneous synthesis of vitamin D. We hypothesized that major changes in keratinization may similarly alter the cutaneous synthesis of vitamin D.
  
  
  OBJECTIVE
  To explore calciotrophic hormones, parameters of bone remodelling and bone mineral density (BMD) in nine patients with non-bullous congenital ichthyosis.
  
  
  METHODS
  Six patients were European, three were North African. Four had received acitretin over a long period of time. A complete biological investigation, including serum and urinary calcium and phosphorus, calciotrophic hormones [intact parathyroid hormone (iPTH), 25-hydroxyvitamin D (25-(OH)D) and 1,25-dihydroxyvitamin D (1,25-(OH)2D)], bone formation and resorption markers, was performed on all patients during the winter season and repeated among four patients after summer. BMD was measured in all patients.
  
  
  RESULTS
  All patients had a marked 25-(OH)D deficiency, clearly below the deficiency threshold of 25 nmol/L. Patients from North Africa had a greater deficiency than European patients, perhaps because of the difference in skin pigmentation. iPTH remained normal in European patients but was elevated among the North Africans. After sun exposure, an improvement in vitamin status was visible in only one patient. Bone formation and resorption markers remained normal. Femoral neck osteodensitometry indicated values near the osteopaenic threshold in two young North African females. No deleterious effect of retinoids on vitamin D metabolism was observed.
  
  
  CONCLUSIONS
  Patients, and in particular pigmented patients, with congenital ichthyosis present a severe deficiency in vitamin D. Care provided to protect the skeletal future of these patients involves measuring BMD and prescribing supplementation.
authors.affiliation: Department of Dermatology, Saint-Louis Hospital, Paris, France. saskia.oro@ch-argenteuil.fr
authors.forename: S
authors.initials: S
authors.lastname: Ingen-Housz-Oro
authors.forename: P
authors.initials: P
authors.lastname: Boudou
authors.forename: C
authors.initials: C
authors.lastname: Bergot
authors.forename: F
authors.initials: F
authors.lastname: Ibrahim
authors.forename: J C
authors.initials: JC
authors.lastname: Souberbielle
authors.forename: L
authors.initials: L
authors.lastname: Dubertret
authors.forename: C
authors.initials: C
authors.lastname: Blanchet-Bardon
mesh_terms: D000293:Adolescent; D000328:Adult; D015519:Bone Density; D016723:Bone Remodeling; D005260:Female; D006801:Humans; D007057:Ichthyosis / Q000209:etiology* / Q000378:metabolism; D008297:Male; D010281:Parathyroid Hormone / Q000378:metabolism; D012880:Skin Pigmentation; D014807:Vitamin D / Q000031:analogs & derivatives* / Q000378:metabolism
chemical_list: D010281:Parathyroid Hormone; D014807:Vitamin D; C104450:25-hydroxyvitamin D