Author(s)

Seiko Yamamoto-Nemoto¹, Rina Shimada¹, Hanako Tajima², Emiko Iwasawa¹, Yoko Shimizu¹, Elif Bahar Tuna³, Kei Ogawa¹, Atsushi Watanabe⁴, Takehiko Shimizu¹

¹Department of Pediatric Dentistry, Nihon University School of Dentistry at Matsudo, Matsudo, Japan.
²Department of Pediatrics, Nippon Medical School, Tokyo, Japan.
³Department of Pediatric Dentistry, Istanbul University Faculty of Dentistry, Istanbul, Turkey.
⁴Department of Molecular and Medical Genetics, Nippon Medical School, Tokyo, Japan.

Hypophosphatasia (HPP) is an inherited skeletal disease caused by mutation of the gene encoding tissue non-specific alkaline phosphatase (TNSALP). Odonto-HPP is well known as the mildest of HPP. The manifestations involve only the teeth, such as premature primary teeth exfoliation caused by reduction of alveolar bone, enlarged dental pulp chamber, and dental defects. We report a case of a 9-years-old boy who developed HPP. He was observed from the primary dentition to the mixed dentition period. At initial presentation at our hospital, he had multiple premature exfoliation of primary teeth and reduction of the alveolar bone. HPP was suspected due to the low level of ALP activity in serum, his oral manifestation, and dental history. He was referred to a physician for the final diagnosis. Therefore his compound heterozygote mutations, c.1559 delT (T/delT) and c.407G > A (G/A), were found in TNSALP and he diagnosed with odonto-HPP. Even though these mutations were reported as being involved in odonto-HPP, his mineral densities tended to be lower than that of his age. It is therefore necessary to investigate the bone mineralization level in odonto-HPP without other bone symptoms. Moreover, ongoing enzyme-replacement therapy in odonto-HPP might improve dental abnormality and bone disorders.

Hypophosphatasia, Odonto-HPP, Tissue Non-Specific Alkaline Phosphatase

Yamamoto-Nemoto, S. , Shimada, R. , Tajima, H. , Iwasawa, E. , Shimizu, Y. , Tuna, E. , Ogawa, K. , Watanabe, A. and Shimizu, T. (2016) Oral Symptoms and Bone Observations in Odonto-Hypophosphatasia. Open Journal of Stomatology, 6, 245-251. doi: 10.4236/ojst.2016.612030.