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Normal growth and muscle dysfunction in X-linked hypophosphatemic rickets associated with a novel mutation in the

Polyzois Makras1, Neveen A T Hamdy, Sarina G Kant

  • 1Department of Endocrinology and Metabolic Diseases, Leiden University Medical Center, Albinusdreef 2, 2333 ZA, Leiden, The Netherlands.

The Journal of Clinical Endocrinology and Metabolism
|February 7, 2008
PubMed

Insights

This study reports a family with X-linked hypophosphatemia (XLH) and a novel PHEX gene mutation who experienced normal growth despite delayed treatment. This challenges typical XLH growth expectations.

Area of Science:

  • Genetics and Molecular Biology
  • Pediatric Endocrinology
  • Rare Diseases

Background:

  • X-linked hypophosphatemia (XLH) is a genetic disorder causing hypophosphatemia and impaired growth.
  • Early intervention is crucial for improving growth outcomes in XLH patients.

Observation:

  • A family with XLH, caused by a novel PHEX gene mutation (IVS4+6T-->C), exhibited unusual clinical features over 30 years.
  • Affected individuals, including a mother and two sons, displayed normal growth despite varying treatment timelines, including no treatment for the mother.

Findings:

  • The novel PHEX mutation led to exon 4 skipping, resulting in a unique phenotype.
  • Two sons achieved normal adult heights despite late phosphate treatment initiation and persistently low serum phosphate levels.
  • Reversible proximal myopathy was observed in one son, resolving over seven years.

Implications:

  • This case highlights that normal growth is achievable in XLH patients with specific PHEX mutations, even with delayed or absent treatment.
  • Further research is needed to understand the genotype-phenotype correlation and the pathophysiological mechanisms underlying this atypical XLH presentation.
Abstract

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