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Osteoporosis International

, Volume 29, Issue 2, pp 511–515 | Cite as

Asfotase alfa treatment for 1 year in a 16 year-old male with severe childhood hypophosphatasia

  • S. A. BowdenEmail author
  • B. H. Adler
Case Report

Abstract

We describe the clinical outcome of asfotase alfa therapy in a 16-year-old boy with severe childhood hypophosphatasia (HPP), who began therapy at age 15 years. The patient was diagnosed with HPP at age 2 years when he presented with genu varum and premature loss of primary teeth. He had a history of multiple fractures requiring 16 orthopedic surgeries with rod and pin placement in his lower extremities. He had chronic skeletal pain and used cane to ambulate with great difficulty. His height Z score at age 15 years was − 5. He had severe scoliosis and deformity of both legs. Bone radiograph showed hypomineralization and characteristic “tongues” of radiolucency in the distal radius and ulna. His serum alkaline phosphatase level was stable, with elevated serum pyridoxal 5′-phosphate and urine phosphoethanolamine, consistent with HPP. He was started on asfotase alfa 2 mg/kg given subcutaneously thrice weekly. He had marked clinical improvement in mobility with no report of pain after 3 months of treatment. At 6 month, he walked without cane and participated in outdoor activities with peers. Bone radiograph at 6 months showed striking improvement in previous radiolucent areas. At 9 months, his annualized growth velocity was 9.5 cm/year, while growth velocity of arm span was 12 cm/year. However, at 12 months, he was noted to have worsening scoliosis from 60 degrees before therapy to 110 degrees, with a slight decrease in height, necessitating a spinal fusion surgery. In conclusion, treatment with asfotase alfa significantly improved physical function, pain, overall quality of life, and skeletal radiographic findings in this patient. Close monitoring for progression of scoliosis in adolescents with HPP treated with asfotase alfa is recommended.

Keywords

Asfotase alfa Hypophosphatasia Scoliosis Short stature 

Abbreviations

HPP

hypophosphatasia

TNSALP

tissue-nonspecific isoenzyme of alkaline phosphatase

PPi

inorganic pyrophosphate

PLP

pyridoxal 5′-phosphate

PEA

phosphoethanolamine

Notes

Acknowledgments

The authors thank Melody Davis, PhD, for her critical review of the manuscript.

Compliance with ethical standards

Conflicts of interest

None.

Consent

The patient’s parent provided written informed consent for publication of this case report.

Supplementary material

198_2017_4267_MOESM1_ESM.docx (881 kb)
ESM 1 (DOCX 881 kb)

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Copyright information

© International Osteoporosis Foundation and National Osteoporosis Foundation 2017

Authors and Affiliations

  1. 1.Division of Endocrinology, Department of PediatricsNationwide Children’s Hospital/The Ohio State University College of MedicineColumbusUSA
  2. 2.Department of RadiologyNationwide Children’s Hospital/The Ohio State University College of MedicineColumbusUSA

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