Bone Abstracts

Background: Hypophosphatasia (HPP) is a heterogeneous disease; it can reveal itself at any age, through a wide range of symptoms. Findings of childhood (juvenile) HPP ranges from low bone mineral density for age with unexplained fractures to rickets, and premature loss of primary teeth with intact roots. We described a boy with the childhood form of hypophosphatasia presenting with short stature without rickets findings.

Case report: An 11-year-old boy was admitted with short stature. He had no complaints other than short stature. Three fractures developed involving left ankle and left forearm as a result of low energy trauma at age of 9 and 10. His eruption of primary teeth delayed until 2.5 year old. Low alkaline phosphatase (ALP) level (65 IU/ml; the lowest normal level for his age is 130 IU/ml) suggested the diagnosis of hypophosphatasia. High serum pyridoxal 5-phosphate level was found 57 μg/l (reference range 5–50 μg/l). His L1–L4 bone mineral density (BMD) by DEXA was normal for age. Tissue nonspecific ALP (TNSALP) gene sequencing revealed the heterozygous pR184W (c.550C>T) mutation. No mutations were detected in both father and mother.

Conclusion: The presence of multipl fractures and delayed primary teeth eruption suggested childhood hypophosphatasia in our case. Although our patient had short stature, there were no findings of rickets and low BMD. The laboratory findings of the patient showed changes at the borderline. But, mutation causing HPP was detected and diagnosis of mild HPP was confirmed. This patient demonstrated that ALP should always be evaluated even if there were no rickets-like findings in every child with short stature.

Disclosure: The authors declared no competing interests.