title: Infantile loss of teeth: odontohypophosphatasia or childhood hypophosphatasia.
abstract: Hypophosphatasia is a hereditary disorder characterized by a deficiency of serum and bone alkaline phosphatase (ALP) activity and defective skeletal mineralization. It is caused by a loss of function mutations in the tissue nonspecific ALP gene (TNSALP) encoding the tissue nonspecific alkaline phosphatase. A 4-year-and-8-month-old girl presented with premature exfoliation of the anterior incisors and canines. Very low ALP level (27 IU/ml) suggested the diagnosis of hypophosphatasia, which was supported by an elevated urine phosphoethanolamine/Cr of 84 μmol/mmol (reference range, <25 μmol/mmol) and serum pyridoxal-5'-phosphate of 393 μg/L (reference range, 3.6-18 μg/L). The phenotype of the patient was subsequently classified as mild childhood hypophosphatasia. TNSALP gene sequencing revealed the homozygous c.382 G > A (p.V128M) mutation. This mutation was previously observed in a series of patients with severe hypophosphatasia, pointing out the possible role of other genetic or environmental factors in the modulation of the hypophosphatasia phenotype.
authors.affiliation: Department of Pediatrics, Division of Pediatric Endocrinology, School of Medicine, Marmara University, Fevzi Cakmak Mah. Mimar Sinan Cad. No:41Pendik, Istanbul, Turkey.
authors.forename: Belma
authors.initials: B
authors.lastname: Haliloglu
authors.forename: Tulay
authors.initials: T
authors.lastname: Guran
authors.forename: Zeynep
authors.initials: Z
authors.lastname: Atay
authors.forename: Saygın
authors.initials: S
authors.lastname: Abali
authors.forename: Etienne
authors.initials: E
authors.lastname: Mornet
authors.forename: Abdullah
authors.initials: A
authors.lastname: Bereket
authors.forename: Serap
authors.initials: S
authors.lastname: Turan
mesh_terms: D002675:Child, Preschool; D005260:Female; D006801:Humans; D007014:Hypophosphatasia / Q000150:complications / Q000175:diagnosis*; D017001:Tooth Demineralization / Q000150:complications / Q000151:congenital* / Q000175:diagnosis; D016388:Tooth Loss / Q000209:etiology*