Adult hypophosphatasia

Radiopaedia • CC-by-nc-sa 3.0 • de

Adult hypophosphatasia is generally considered a milder form of hypophosphatasia.

It is usually classified as hypophosphatasia occurring after 18 years of age and typically diagnosed after middle age . It is normally not associated with low bone mass in general but can be have considerable heterogeneity and can have a range of clinical features which include.

  • history of recurrent fractures / pseudofractures ~ 40
  • recurring headaches ~55%
  • recurring muscle pain
  • severe muscle weakness
  • dental abnormalities - early loss of teeth
  • chronic bone / muscle pain
  • delayed bone healing
  • osteomalacia
  • arthropathy +/- chondrocalcinosis
  • enthesopathy
  • altered gait

Pathology

Markers

A reduced enzymatic activity of alkaline phosphatase (ALP) is the key marker of the disease, causing an accumulation of ALP substrates such as pyridoxal-5-phosphate (PLP).