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Hypophosphatasia mimicking hypoxic–ischaemic encephalopathy: early recognition and management
  1. Aled Picton1,
  2. Ruchi Nadar2,
  3. Alexandra Pelivan1,
  4. Vidya Garikapati1,
  5. Vrinda Saraff2
  1. 1 Neonatal Unit, Birmingham Heartlands Hospital, University Hospitals Birmingham NHS Foundation Trust, Birmingham, UK
  2. 2 Department of Paediatric Endocrinology and Diabetes, Birmingham Women's and Children's NHS Foundation Trust, Birmingham, UK
  1. Correspondence to Dr Vrinda Saraff, Department of Paediatric Endocrinology and Diabetes, Birmingham Women's and Children's NHS Foundation Trust, Birmingham, United Kingdom; vrinda.saraff{at}


Background Hypophosphatasia (HPP) is a rare inherited disorder affecting bone and teeth development. Perinatal HPP is the most severe form and associated with a high mortality. Features include respiratory distress, skeletal abnormalities and low alkaline phosphatase (ALP) activity.

Case A baby boy developed respiratory distress, hypotonia and seizures within an hour of birth. Blood gas showed mixed acidosis and abnormal base deficit. Hypoxic–ischaemic encephalopathy (HIE) was suspected and managed with therapeutic hypothermia. Subsequent investigations identified low ALP activity and abnormal bone mineralisation, leading to a diagnosis of HPP. On day 5 of life, enzyme replacement therapy (ERT) was commenced, its first use via direct NHS England funding since UK licensing in 2017.

Conclusions Early hypotonia is an atypical presentation for perinatal HPP. Combined with acidosis and encephalopathy, it can clinically mimic HIE. Early recognition of biochemical and radiological features of HPP is essential for rapid diagnosis and timely initiation of life-saving ERT.

  • bone disease
  • neonatology
  • therapeutics
  • bone metabolism

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  • Contributors APi led the case report writing process. All authors reviewed the child’s clinical record for data extraction and contributed to the manuscript.

  • Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.

  • Competing interests VS was a clinical study investigator and received honoraria and travel support from Alexion Pharmaceuticals for participation on advisory boards.

  • Patient consent for publication Parental/guardian consent obtained.

  • Provenance and peer review Not commissioned; externally peer reviewed.

  • Data availability statement Data sharing not applicable as no datasets generated and/or analysed for this study.