Hypophosphatasia in childhood: Diagnosis to management

Abstract

Hypophosphatasia (HPP) is a rare inherited metabolic bone disorder caused by loss-of-function mutations in the ALPL gene, leading to deficient activity of tissue-nonspecific alkaline phosphatase (TNSALP). HPP is diagnosed based on a combination of clinical features, laboratory findings, radiographic findings, and DNA analysis identifying a pathogenic variant of ALPL. Based on the clinical heterogeneity of HPP, the diagnosis of HPP is very challenging. However, the introduction of asfotase alfa, a bone-targeted recombinant TNSALP, has improved the prognosis. Early diagnosis of HPP is essential for timely initiation of enzyme replacement therapy (ERT). This review aims to provide an updated current knowledge on the genetic basis, pathophysiology, epidemiology, clinical classification, diagnosis, and management of HPP, with particular emphasis on ERT and emerging diagnostic approaches.