• Journal of The Korean Society of Inherited Metabolic disease
• /
• v.16 no.3
• /
• pp.141-147
• /
• 2016

Hypophosphatasia is caused by the mutations in ALPL, which encodes tissue-nonspecific alkaline phosphatase (TNSALP). It can be inherited either in an autosomal dominant or recessive manner. Clinically, hypophophosphatasia is characterized by skeletal findings similar to those in rickets or osteomalacia, but serum alkaline phosphatase levels are decreased in the affected patients. Hypophosphatasia can be classified into six clinical forms according to age at diagnosis and severity of symptoms: perinatal lethal, infantile, childhood, adult, odontohypophosphatasia, and perinatal benign. As being a very rare disease, only one case has been reported in Korean population. Here we describe a case with perinatal benign hypophosphatasia with recessive ALPL mutations. Bowing of lower legs was detected in prenatal period and low serum alkaline phosphatase level was noted after birth. During the follow-up evaluation for 4.5 years, bone mineralization and legs bowing were improved but the growth retardation was persistent. As the recombinant bone-targeted human TNSALP became available, the clinical improvement of the affected patients is expected including the case described here with this treatment. More efforts are needed to identify the cases affected by hypophosphatasia.