Japanese nationwide survey of hypophosphatasia reveals prominent differences in genetic and dental findings between odonto and non-odonto types

Hypophosphatasia (HPP) is a rare and intractable metabolic bone disease caused by mutations in the ALPL gene. Here, we undertook a nationwide survey of HPP in Japan, specifically regarding the prominent genetic and dental manifestations of odonto (n = 16 cases) and other (termed “non-odonto”) (n = 36 cases) types. Mean serum alkaline phosphatase (ALP) values in odonto-type patients were significantly greater than those of non-odonto-type patients (PALPL “c.1559delT” mutation, associated with extremely low ALP activity, was found in approximately 70% of cases. Regarding dental manifestations, all patients classified as odonto-type showed early exfoliation of the primary teeth significantly more frequently than patients classified as non-odonto-type (100% vs. 56%; PP低磷酸酯酶症（Hypophosphatasia, HPP）是一类由ALPL基因（ALPL gene）突变诱发的罕见难治性代谢性骨病。本研究针对日本国内的HPP病例开展全国性调查，重点分析牙型（odonto-type，n=16例）与非牙型（non-odonto型，n=36例）患者的典型遗传与牙科表型。牙型患者的血清碱性磷酸酶（alkaline phosphatase, ALP）平均水平显著高于非牙型患者；约70%的病例携带与极低ALP活性相关的c.1559delT突变。在牙科表型方面，牙型患者的乳牙早脱发生率显著高于非牙型患者（100% vs. 56%；PP