title: [Vitamin D supplementation: not too much, not too little!].
abstract: Vitamin D deficiency is common in the general population and even more frequent in patients with chronic diseases. The prevention of rickets with native vitamin D supplementation is one of the oldest and most effective prophylactic measures ever reported in medicine, leading to an almost complete eradication of vitamin D-deficient rickets in developed countries. We report on two children with vitamin D abnormalities: the first, 10-year-old child developed rickets without any vitamin D supplementation despite different risk factors (autism, ethnicity, nutritional problems, chronic antiepileptic therapies). In contrast, the second, 8-month-old child received double doses of native vitamin D from birth for several months and was referred for acute and symptomatic hypercalcemia. As such, vitamin D supplementation must follow specific rules: neither too much nor too little! We also discuss the emergence of "new" genetic diseases such as mutations in the 24-hydroxylase (CYP24A1) gene inducing neonatal hypercalcemia and nephrocalcinosis: we believe that before prescribing conventional vitamin D supplementation as recommended by the national guidelines, pediatricians should quickly rule out a potential genetic abnormality in phosphate/calcium metabolism (namely a history of lithiasis or hypercalcemia) that would lead to further biological investigations.
authors.affiliation: Service de néphrologie rhumatologie dermatologie pédiatriques, centre de référence des maladies rénales rares, hôpital Femme-Mère-Enfant, 59, boulevard Pinel, 69677 Bron cedex, France.
authors.forename: S
authors.initials: S
authors.lastname: Hamo
authors.affiliation: Service de néphrologie rhumatologie dermatologie pédiatriques, centre de référence des maladies rénales rares, hôpital Femme-Mère-Enfant, 59, boulevard Pinel, 69677 Bron cedex, France; Faculté de médecine Lyon-Est, université de Lyon, 69008 Lyon, France.
authors.forename: C
authors.initials: C
authors.lastname: Freychet
authors.affiliation: Service de néphrologie rhumatologie dermatologie pédiatriques, centre de référence des maladies rénales rares, hôpital Femme-Mère-Enfant, 59, boulevard Pinel, 69677 Bron cedex, France.
authors.forename: A
authors.initials: A
authors.lastname: Bertholet-Thomas
authors.affiliation: Service de neurologie pédiatrique, hôpital Femme-Mère-Enfant, 69677 Bron cedex, France.
authors.forename: A-L
authors.initials: AL
authors.lastname: Poulat
authors.affiliation: Service de néphrologie rhumatologie dermatologie pédiatriques, centre de référence des maladies rénales rares, hôpital Femme-Mère-Enfant, 59, boulevard Pinel, 69677 Bron cedex, France; Faculté de médecine Lyon-Est, université de Lyon, 69008 Lyon, France.
authors.forename: P
authors.initials: P
authors.lastname: Cochat
authors.affiliation: Faculté de médecine Lyon-Est, université de Lyon, 69008 Lyon, France; Service de neurologie pédiatrique, hôpital Femme-Mère-Enfant, 69677 Bron cedex, France; Service de rééducation fonctionnelle pédiatrique, hôpital Femme-Mère-Enfant, 69677 Bron cedex, France.
authors.forename: C
authors.initials: C
authors.lastname: Vuillerot
authors.affiliation: Service de néphrologie rhumatologie dermatologie pédiatriques, centre de référence des maladies rénales rares, hôpital Femme-Mère-Enfant, 59, boulevard Pinel, 69677 Bron cedex, France; Faculté de médecine Lyon-Est, université de Lyon, 69008 Lyon, France. Electronic address: justine.bacchetta@chu-lyon.fr.
authors.forename: J
authors.initials: J
authors.lastname: Bacchetta
mesh_terms: D002648:Child; D019587:Dietary Supplements; D006801:Humans; D006934:Hypercalcemia / Q000139:chemically induced*; D008297:Male; D012279:Rickets / Q000188:drug therapy* / Q000209:etiology; D014807:Vitamin D / Q000008:administration & dosage* / Q000009:adverse effects*; D014808:Vitamin D Deficiency / Q000188:drug therapy*; D014815:Vitamins / Q000009:adverse effects*
chemical_list: D014815:Vitamins; D014807:Vitamin D