Lack of evidence for hypophosphatasia as a factor in the pathogenesis of early-onset periodontitis.

Hypophosphatasia, an inheritable metabolic disorder affecting calcification, has been shown to have various oral manifestations. Recently, it was suggested that it may serve as a predisposing factor in the pathogenesis of early-onset periodontitis. The present study was designed to examine the frequency of hypophosphatasia among patients with juvenile periodontitis and rapidly progressive periodontitis. Eighteen patients, nine females and nine males (age 19-37 years, mean 23.2 years), were included in this study. Venous blood and urinary samples were collected and assayed for alkaline phosphatase and urinary phosphoethanolamine. Mean alkaline phosphatase levels (109 +/- 35 IU/L) were within the normal limits for all patients except one who exhibited slightly lower than normal values. Urinary phosphoethanolamine, a typical marker of hypophosphatasia, was absent from all specimens, which rules out the possible diagnosis of such disorder in these patients. Until more information is available, the role of hypophosphatasia as a predisposing factor in early-onset periodontitis is yet to be established.