The Clinical Picture of Patients Suffering from Hypophosphatasia—A Rare Metabolic Disease of Many Faces

Hypophosphatasia (HPP) is a rare, and usually diagnosed with delay, genetic disease caused by a mutation in the alkaline phosphatase liver/bone/kidney type (ALPL) gene. Low activity of the alkaline phosphatase (ALP) impairs the hydroxyapatite formation, reducing skeletal mineralization. The aim of the study was to present patients diagnosed with HPP. The data from the history and medical records of patients were analyzed. In the study group, one patient was diagnosed with perinatal type of HPP, three were diagnosed with infant variant, eight were diagnosed with children variant, two were diagnosed with odontohypophosphatasia, and two were diagnosed with the adult type of the disease. The most frequently presented symptoms included premature loss of teeth in 11/16 (68.75%) patients, bone deformities in 10/16 (62.5%) patients, chronic bone pain in 9/16 (56.25%) patients, and fractures in 8/16 (50%) patients. Reduction in bone mineral density in at least one examined projection has been found in 11/14 patients. Conclusions: The correct diagnosis of HPP is difficult due to the variety of types and clinical symptoms, as well as the very rare occurrence of this disease. Both lower and upper reference values of the determined biochemical parameters may be important in HPP diagnostics.