title: Low bone mineral content and challenges in interpretation of dual-energy X-ray absorptiometry in children with mucopolysaccharidosis types I, II, and VI.
abstract: Osteoporosis has been described in animal models of mucopolysaccharidosis (MPS). Whether clinically significant osteoporosis is common among children with MPS is unknown. Therefore, cross-sectional data from whole body (WB; excluding head) and lumbar spine (LS) bone mineral density (BMD) compared with sex-, chronologic age-, and ethnicity-matched healthy individuals (Zage), height-for-age (HAZ) Z-score (ZHAZ) and bone mineral content (BMC) measured by dual-energy X-ray absorptiometry (DXA) in 40 children with MPS were analyzed. A subset of these children (n=24) was matched 1:3 by age and sex to a group of healthy children (n=72) for comparison of BMC adjusted for Tanner stage, race, lean body mass, height, and bone area. Low BMD Z-score was defined as Z-score of -2 or less. In children with MPS, 15% had low WB Zage and 48% had low LS Zage; 0% and 6% had low WB ZHAZ and low LS ZHAZ, respectively. Adjusted WB BMC was lower in MPS participants (p=0.009). In conclusion, children with MPS had deficits in WB BMC after adjustments for stature and bone area. HAZ adjustment underestimated bone deficits (i.e., overestimated WB BMD Z-scores) in children with MPS likely owing to their abnormal bone shape. The influence of severe short stature and bone geometry on DXA measurements must be considered in children with MPS to avoid unnecessary exposure to antiresorptive treatments.
authors.affiliation: Division of Endocrinology, Department of Pediatrics, University of Minnesota, Minneapolis, MN, USA. Electronic address: polgr001@umn.edu.
authors.forename: Lynda E
authors.initials: LE
authors.lastname: Polgreen
authors.affiliation: Division of Biostatistics, School of Public Health, University of Minnesota, Minneapolis, MN, USA.
authors.forename: William
authors.initials: W
authors.lastname: Thomas
authors.affiliation: Children's Hospital & Research Center at Oakland, Oakland, CA, USA.
authors.forename: Ellen
authors.initials: E
authors.lastname: Fung
authors.affiliation: Division of Medical Genetics, University of Utah, Salt Lake City, UT, USA.
authors.forename: David
authors.initials: D
authors.lastname: Viskochil
authors.affiliation: Division of Medical Genetics, University of Utah, Salt Lake City, UT, USA.
authors.forename: David A
authors.initials: DA
authors.lastname: Stevenson
authors.affiliation: Division of Cardiology, Department of Pediatrics, University of Minnesota, Minneapolis, MN, USA.
authors.forename: Julia
authors.initials: J
authors.lastname: Steinberger
authors.affiliation: Division of Blood and Marrow Transplant, Department of Pediatrics, University of Minnesota, Minneapolis, MN, USA.
authors.forename: Paul
authors.initials: P
authors.lastname: Orchard
authors.affiliation: Division of Genetics & Metabolism, Department of Pediatrics, University of Minnesota, Minneapolis, MN, USA.
authors.forename: Chester B
authors.initials: CB
authors.lastname: Whitley
authors.affiliation: Department of Medicine, University of Minnesota, Minneapolis, MN, USA.
authors.forename: Kristine E
authors.initials: KE
authors.lastname: Ensrud
mesh_terms: D015502:Absorptiometry, Photon; D000293:Adolescent; D000367:Age Factors; D001827:Body Height; D015519:Bone Density; D001846:Bone Development; D016022:Case-Control Studies; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D008297:Male; D009083:Mucopolysaccharidoses / Q000150:complications*; D010024:Osteoporosis / Q000453:epidemiology*
keywords: Bone mineral content; bone mineral density; mucopolysaccharidoses; osteoporosis; skeletal dysplasia
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