Brief Clinical Report: Hypophosphatasia—Diagnostic Considerations and Treatment Outcomes in an Infant

Abstract

Hypophosphatasia (HPP) is a rare, inherited metabolic bone disorder characterized by low serum alkaline phosphatase activity and impaired bone mineralization. Clinical manifestations and severity of symptoms vary widely in HPP, ranging from in utero death to isolated dental manifestations in adults. Treatment with enzyme replacement therapy has been reported to improve outcomes in perinatal, infantile, and childhood forms of HPP. Here, we present a case of a boy with poor linear growth, mild limb bowing, and radiographic rickets who was diagnosed with HPP before 6 months of age. Treatment with enzyme replacement therapy was initiated at 7 months of age, after which significant improvements in radiographic findings and linear growth were demonstrated. This case highlights several important challenges in the diagnosis, classification, and management of HPP.

Case Report: Efficacy of Reduced Doses of Asfotase Alfa Replacement Therapy in an Infant With Hypophosphatasia Who Lacked Severe Clinical Symptoms

“…Recently, the beneficial effects of AA therapy on adult and adolescent patients with mild symptoms have been reported (18). Furthermore, AA therapy for a male infant patient with limited disease manifestation (e.g., poor linear growth, mild limb bowing, and radiographic rickets) resulted in considerable improvement of his symptoms (19). Thus far, conservative management with periodic follow-up is recommended for patients with childhood HPP who exhibit mild or no symptoms; at the onset of any functional limitations, the initiation of AA therapy is recommended (11).…”

Dental manifestations of hypophosphatasia in children and the effects of enzyme replacement therapy on dental status: A series of clinical cases

“…Currently, the only effective treatment option for HPP is enzyme replacement therapy with asfotase alfa . Published data demonstrate significant success in using this drug for the treatment of the most severe forms of HPP (prenatal and infantile) and describe the increase in bone mineral density and improvement in respiratory and motor functions . Some authors advise prescription of asfotase alfa to patients with the childhood form of HPP and odontohypophosphatasia, who were carefully selected by evaluating the severity of signs and symptoms, the expected benefit, and the potential risks .…”