Identifying adult hypophosphatasia in the rheumatology unit

Introduction The most frequent manifestation in adult hypophosphatasia is musculoskeletal pain. The unspecific nature of its clinical presentation may prevent correct diagnosis.

Methods Over a period of 10 years 9,522 patients were screened in a rheumatological outpatient unit. Serum alkaline phosphatase levels≤40 U/l were found in 524 patients. After screening for secondary causes, 73 patients were invited for clinical evaluation. Genetic testing was performed in 23 patients with suspected hypophosphatasia. Logistic regression models were used to estimate the association of each clinical factor with hypophosphatasia.

Results Mutations in the ALPL gene were observed in 57% of genetically screened patients. Arthralgia, fractures and pain were the leading symptoms in hypophosphatasia patients. Chondrocalcinosis (OR 29.12; 95% CI 2.02-1593.52) and dental disease (OR 8.33; 95% CI 0.93-143.40) were associated with hypophosphatasia independent of body mass index. Onset of symptoms in hypophosphatasia was at 35.1 (14.3) years, with a mean duration from symptoms to diagnosis of 14.4 (8.1) years. Bone mineral density and trabecular bone score as well as bone turnover markers were not indicative for hypophosphatasia.

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Discussion Hypophosphatasia can mimic joint diseases. Thus, in patients with uncertain rheumatologic complaints and low alkaline phosphatase, hypophosphatasia should be considered as potential diagnosis.

Keywords Hypophosphatasia, HPP, arthralgia, alkaline phosphatase, chondrocalcinosis

Korrespondenzadresse Benjamin Hadzimuratovic, Hanusch-Krankenhaus der ÖGK, Ludwig Boltzmann-Institut für Osteologie der ÖGK und AUVA , I. Medizinische Abteilung , Heinrich-Collin-Straße 30, 1140 Wien , Österreich, E-Mail: [e-mail]

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Artikel online veröffentlicht:
08. September 2022