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Low bone mineral density in achondroplasia and hypochondroplasia
Author(s) -
Matsushita Masaki,
Kitoh Hiroshi,
Mishima Kenichi,
Kadono Izumi,
Sugiura Hiroshi,
Hasegawa Sachi,
Nishida Yoshihiro,
Ishiguro Naoki
Publication year - 2016
Publication title -
pediatrics international
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.49
H-Index - 63
eISSN - 1442-200X
pISSN - 1328-8067
DOI - 10.1111/ped.12890
Subject(s) - medicine , achondroplasia , bone mineral , pediatrics , osteoporosis
Abstract Background Achondroplasia (ACH) and hypochondroplasia (HCH) are the most common form of short‐limb skeletal dysplasias caused by activated fibroblast growth factor receptor 3 ( FGFR3 ) signaling. Although decreased bone mass was reported in gain‐of‐function mutation in Fgfr3 mice, both disorders have never been described as osteoporotic. In the present study, we evaluated bone mineral density (BMD) in ACH and HCH patients. Methods We measured spinal BMD (L1–L4) in 18 ACH and four HCH patients with an average age of 19.8 ± 7.5 years (range, 10–33 years). BMD Z‐score in each individual was calculated for normalizing age and gender. Correlation between body mass index (BMI) and BMD was analyzed. Moreover, BMD and Z‐score were compared between ACH patients and HCH patients. Results The average BMD of ACH/HCH patients was 0.805 ± 0.141 g/cm 2 (range, 0.554–1.056 g/cm 2 ), resulting in an average Z‐score of −1.1 ± 0.8 (range, −2.4 to 0.6) of the standard value. A slightly positive correlation was observed between BMI and BMD ( r = 0.45; P = 0.13). There was no significant difference in BMD and Z‐score between ACH and HCH patients. Conclusion Spinal BMD was reduced in ACH/HCH patients, and was mildly correlated with individual BMI. We should carefully monitor BMD and examine osteoporosis‐related symptoms in adolescent and adult ACH/HCH patients. © 2016 Japan Pediatric Society.