Case Report

Hypophosphatasia: Novel Mutation Associated With An Atypical Newborn Presentation

10.4274/jcrpe.galenos.2019.2018.0263

  • Roger Esmel-Vilomara
  • Susana Hernández
  • Ariadna Campos-Martorell
  • Eva González-Roca
  • Diego Yeste
  • Félix Castillo

Received Date: 04.11.2018 Accepted Date: 25.03.2019 J Clin Res Pediatr Endocrinol 0;0(0):0-0 [e-Pub] PMID: 30929401

Hypophosphatasia, a rare genetic disease affecting bone metabolism, is characterized by decreased activity of tissue nonspecific alkaline phosphatase (TNAP). The gene encoding TNSP (ALPL) has considerable allelic heterogeneity, which could explain different degrees of enzyme activity determining a wide clinical variability. We report the case of a preterm newborn in whom a corneal opacity was detected at birth. Blood tests performed to investigate this finding showed low alkaline phosphatase concentrations. The corneal opacity disappeared within a week but alkaline phosphatase remained persistently low. With persistently decreased levels of alkaline phosphatase, upon suspicion of hypophosphatasia, plain radiography detected changes suggestive of rickets. Sequencing of the ALPL gene revealed a heterozygous variant that has not been described in the literature to date.

Our patient’s condition could be an atypical neonatal form of the syndrome, with a mild phenotype, very different from the classic neonatal form which can lead to severe skeletal disease and respiratory failure. However, it could also be an early diagnosis of the childhood form, with better prognosis.

Keywords: Hypophosphatasia, mutation, newborn, alkaline phosphatase