Adult hypophosphatasia. Current aspects

Hypophosphatasia is an inborn metabolic disorder in which abnormally low le vels of the enzyme nonspecific alkaline phosphatase result in defective ske letal and dental mineralization (rickets, fractures, dental abnormalities) and in accumulation of the enzyme substrates (phosphoethanolamine, pyridoxa l-5'phosphate and inorganic pyrophosphate). The build-up of inorganic pyrop hosphate promotes the development of articular chondrocalcinosis. There are several forms of hypophosphatasia, with wide variations in severity. We report the case of a 53-year-old man with typical manifestations of mode rate adulthood hypophosphatasia. Investigations in his family found the dis ease in a sister and two children. He had two autosomal mutations, which we re transmitted recessively. Several mutations of the alkaline phosphatase gene have been identified. Th e genotype is correlated with the phenotype: some mutations are associated with milder forms and others with more severe forms of the disease. Joint B one Spine 2001 ; 68 : 120-4. (C) 2001 Editions scientifiques et medicales E lsevier SAS.