Long-term follow-up of bone mineral density in childhood hypophosphatasia.
OBJECTIVE
Hypophosphatasia (HP; MIM 241510) is an inborn error of bone metabolism, characterized by a genetic defect in the gene of the tissue-non-specific alkaline phosphatase TNSALP. Long-term data on bone mineral density measurements are not available.


METHODS
We have analyzed changes of bone mineral density (pQCT and DXA) prospectively during 4years of follow-up in a cohort of 6 patients with childhood HP.


RESULTS
At diagnosis hypermineralization of the trabecular bone in the metaphyseal area of long bones in affected children was noted. During 4 years of follow-up a gradual, significant decrease of mineralization was noted in the radial metaphyses. In contrast, BMC by DXA and total body DXA values were stable in comparison to healthy controls. During follow-up a systemic hyperprostaglandinism was documented in the majority of the patients. Non-steroidal anti-inflammatory drug treatment was evaluated by measuring prostaglandin excretion in the urine.


CONCLUSIONS
Metaphyseal hypermineralization in childhood HP, which might be a compensation for a mechanically incompetent bony structure, decreased over time. There might be a pathophysiological link to continually elevated systemic prostaglandins.
Girschick
Hermann Josef
HJ
Children's Hospital, Section of pediatric rheumatology and osteology, Universitäts-Kinderklinik, University of Würzburg, Josef-Schneider-Strasse 2, Würzburg 97080, Germany. hermann.girschick@mail.uni-wuerzburg.de
Haubitz
Imme
I
Hiort
Olaf
O
Schneider
Peter
P
D015502:Absorptiometry, Photon; D000293:Adolescent; D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000627:therapeutic use; D015415:Biomarkers / Q000097:blood; D015519:Bone Density; D002113:Calcification, Physiologic; D002648:Child; D002675:Child, Preschool; D015331:Cohort Studies; D005500:Follow-Up Studies; D006801:Humans; D007014:Hypophosphatasia / Q000000981:diagnostic imaging* / Q000188:drug therapy / Q000378:metabolism; D008297:Male; D011453:Prostaglandins / Q000652:urine; D012044:Regression Analysis; D014057:Tomography, X-Ray Computed
D000894:Anti-Inflammatory Agents, Non-Steroidal; D015415:Biomarkers; D011453:Prostaglandins