Abstract
Hypophosphatasia (HPP) is a genetic disorder of bone system with the main symptoms of “impaired bone calcification” and “early deciduous tooth drop-off under 4 years of age”. In 2012, the Department of Pediatric Dentistry, Osaka University Dental Hospital opened an outpatient department specializing in dentistry for bone system diseases, and has been managing the oral cavity of HPP patients in collaboration with the Department of Pediatrics. In addition, since 2015, we have been aiming to build a system that leads to early diagnosis by referring suspected cases to the medical field through screening at dental facilities. The present paper summarizes our activities so far by conducting a fact-finding survey of HPP patients who visited our department and an analysis focusing on odontohypophosphatasia with little knowledge acquired to date. Searching for HPP patients who visited our department in the last 5 years from April 2015, about 24 cases were extracted, and more than 1/3 of them were diagnosed after being referred to our department from a nearby dental clinic. This suggests that an early screening system has been constructed in the area around our hospital. It was also revealed that dental symptoms were the first to be detected in more than half of the cases. In addition, there were some cases in which problems with growth and development were noticed but no diagnosis was given. It was revealed that 11 cases of the odonto HPP had significantly more autosomal dominant inheritance than cases of other hypophosphatasia. Additionally, it was shown that the ALP value at the time of diagnosis was significantly high and close to the normal value. Since the reports of the mild cases are scarce, it is considered that dissemination of the findings obtained in this study may contribute to the development of the conventional early diagnosis system.
https://ror.org/035t8zc32 
