Clinical phenotype, diagnostics, strategy of hypophosphatasia therapy due to ALPL gene mutations in pediatric and adult patients

Hypophosphatasia (HPP) ORPHA 436 is a rare disease with an autosomal recessive/autosomal dominant mode of inheritance due to mutations in the ALPL gene mapped on chromosome 1p36.12, encoding a nonspecific tissue isoenzyme alkaline phosphate (TNSALP). Currently, there are more than 400 known mutations in the ALPL gene. HPF is characterized by variability of manifestations from a mild course with minor damage to bones and teeth to severe forms with damage to the nervous system, lungs, and kidneys. In different countries, data on the prevalence of HPP differ, the average prevalence of severe forms is ~ 3.3 cases per 1 million newborns. In Europe, the prevalence of severe forms is 1: 300000 and moderately severe 1: 63701. The prevalence of mild HPP is thought to be much higher. The expected prevalence of severe forms in the Russian Federation is 1: 100000. GPP is diagnosed in patients of any age (with manifestation in utero, in childhood, or in adulthood).

HPP is an orphan disease, occurring in patients with damage to many organs and systems: bone (osteoporosis, rickets, fractures, growth retardation), lungs (hypoplasia of the lungs, respiratory failure), central nervous system (vitamin B-dependent convulsions), kidney (calciuria, nephrocalcinosis, chronic kidney disease). In the absence of timely enzyme replacement therapy for severe forms of HPP, characterized by a progressive course, the prognosis for life is unfavorable. The only effective treatment for patients is enzyme replacement therapy in combination with symptomatic therapy. The article presents the features of the phenotype and genotype, clinical forms of HPP (perinatal severe, lethal, perinatal benign, infant, pediatric, adult, and odontohypophosphatasia), methods of early diagnosis, the strategy of pathogenetic enzyme replacement therapy of severe and moderate forms in pediatric and adult patients. In the absence of a timely diagnosis, pathogenetic treatment of GFF, there is a high risk of progression with disability and death.

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