Adult Hypophosphatasia in a Middle-Aged Patient With Recurrent Fractures: Prevention of New Fractures With Asfotase Alfa

Hypophosphatasia (HPP) is a rare inherited bone disorder with systemic symptoms, which vary depending on the time of onset and other factors. It may be fatal or cause severe clinical symptoms in infants and children. By comparison, adult HPP generally has a more favorable prognosis, and it is usually associated with chronic pain, recurrent fractures, and impaired quality of life. However, the diagnosis of adult HPP is often delayed or it may remain undiagnosed. Additionally, treatment options for adult HPP are not well established. We report a male patient in his 50s who experienced recurrent fractures in his 40s and 50s, together with chronic pain. He was diagnosed with HPP due to low serum alkaline phosphatase levels and a heterozygous missense variant of the ALPL gene (c.529G>A). He therefore started enzyme replacement therapy with asfotase alfa. After 12 months of treatment with asfotase alfa, his motor function showed marked improvement and he experienced fewer falls and no new fragility fractures, although his chronic pain remained.