title: Neonatal transient hypophosphatemic hypercalciuric rickets in dizygous twins: A role for maternal alendronate therapy before pregnancy or antireflux medications?
abstract: BACKGROUND
  Bisphosphonates (BP) are sometimes used in children and young women, but their use requires expertise and caution due to the relative lack of long-term efficacy and safety data.
  
  
  METHODS
  We report on two dizygotic male twins with a past of mild prematurity who presented at the age of 2 months with moderate clinical craniotabes, hypophosphatemia, normal circulating calcium, severe hypercalciuria, and low parathyroid hormone levels. Following supplementation with oral phosphorus and native vitamin D, the clinical and biological abnormalities disappeared within 2 months. Since the twins were dizygotic and were identical in terms of clinical presentation and progression, the only likely explanation for these transient mineral abnormalities was prenatal or neonatal exposure to a toxic agent. Taking into account their medical past, two drugs were possibly involved: either oral alendronate that their mother had received before pregnancy for misdiagnosed osteoporosis or antireflux medications, or both.
  
  
  CONCLUSIONS
  We believe that these two cases could correspond to the first description of a potential mother-to-fetus transmission of alendronate, inducing early and transient hypophosphatemic rickets, the clinical picture being worsened by the antireflux drugs impairing intestinal phosphate absorption. For pediatric rheumatologists, this raises the question of more clearly defining the indications for BP in female children and teenagers; for rheumatologists, this also demonstrates the importance of correctly diagnosing osteoporosis and not using BP off-label, especially in women of child-bearing age.
authors.affiliation: Service de néphrologie, rhumatologie et dermatologie pédiatriques, Centre de référence des maladies rénales rares, hôpital Femme Mère Enfant, 59, boulevard Pinel, 69677 Bron, France; Département de pédiatrie, CHU de Grenoble, 38043 Grenoble, France.
authors.forename: M
authors.initials: M
authors.lastname: Gerin
authors.affiliation: Service de néonatologie, hôpital Femme Mère Enfant, 69500 Bron, France.
authors.forename: G
authors.initials: G
authors.lastname: Jambon
authors.affiliation: Centre orthopédique Santy, 69008 Lyon, France.
authors.forename: A
authors.initials: A
authors.lastname: Fouque-Aubert
authors.affiliation: Service d'urgences pédiatriques, hôpital Femme Mère Enfant, 69500 Bron, France.
authors.forename: C
authors.initials: C
authors.lastname: Raybaud
authors.affiliation: Service de néphrologie, rhumatologie et dermatologie pédiatriques, Centre de référence des maladies rénales rares, hôpital Femme Mère Enfant, 59, boulevard Pinel, 69677 Bron, France; Département de pédiatrie, CHU de Grenoble, 38043 Grenoble, France; Service de néonatologie, hôpital Femme Mère Enfant, 69500 Bron, France; Centre orthopédique Santy, 69008 Lyon, France; Service d'urgences pédiatriques, hôpital Femme Mère Enfant, 69500 Bron, France; Faculté de médecine Lyon Est, université de Lyon, 69008 Lyon, France.
authors.forename: P
authors.initials: P
authors.lastname: Cochat
authors.affiliation: Service de néonatologie, hôpital Femme Mère Enfant, 69500 Bron, France; Centre orthopédique Santy, 69008 Lyon, France; Service d'urgences pédiatriques, hôpital Femme Mère Enfant, 69500 Bron, France; Faculté de médecine Lyon Est, université de Lyon, 69008 Lyon, France.
authors.forename: O
authors.initials: O
authors.lastname: Claris
authors.affiliation: Service de néphrologie, rhumatologie et dermatologie pédiatriques, Centre de référence des maladies rénales rares, hôpital Femme Mère Enfant, 59, boulevard Pinel, 69677 Bron, France; Département de pédiatrie, CHU de Grenoble, 38043 Grenoble, France; Service de néonatologie, hôpital Femme Mère Enfant, 69500 Bron, France; Centre orthopédique Santy, 69008 Lyon, France; Service d'urgences pédiatriques, hôpital Femme Mère Enfant, 69500 Bron, 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: D019386:Alendronate / Q000009:adverse effects; D000897:Anti-Ulcer Agents / Q000009:adverse effects; D050071:Bone Density Conservation Agents / Q000009:adverse effects; D064098:Esomeprazole / Q000009:adverse effects; D005260:Female; D006801:Humans; D053565:Hypercalciuria / Q000139:chemically induced*; D007223:Infant; D008297:Male; D010281:Parathyroid Hormone / Q000097:blood; D011247:Pregnancy; D011297:Prenatal Exposure Delayed Effects; D063730:Rickets, Hypophosphatemic / Q000139:chemically induced*; D014429:Twins, Dizygotic
chemical_list: D000897:Anti-Ulcer Agents; D050071:Bone Density Conservation Agents; D010281:Parathyroid Hormone; D064098:Esomeprazole; D019386:Alendronate