The role of fibroblast growth factor 23 for hypophosphatemia and abnormal regulation of vitamin D metabolism in patients with McCune-Albright syndrome.
McCune-Albright syndrome (MAS) is sometimes complicated by hypophosphatemia and abnormally low levels of 1,25(OH)(2)D in the presence of hypophosphatemia. Recently, fibroblast growth factor 23 (FGF-23) was reported as a phosphaturic and a causal factor of abnormal vitamin D metabolism. This abnormal phosphate and vitamin D metabolism is well known to be found in oncogenic and X-linked hypophosphatemia. We furthermore reported increased circulating plasma FGF-23 levels in patients with oncogenic and X-linked hypophosphatemia. To determine whether FGF-23 may be involved in the pathogenesis of MAS, we measured plasma FGF-23 levels in six MAS patients. As a control for hypophosphatemia, we also investigated the plasma FGF-23 levels in two patients with hereditary hypophosphatemic rickets with hypercalciuria (HHRH). We also investigated the correlation of plasma FGF-23 levels with serum phosphate and 1,25(OH)(2)D levels after short-term pamidronate therapy in three MAS patients. Plasma FGF-23 levels were significantly increased in patients with MAS compared to normal controls, whereas they were not increased in HHRH patients. Serum phosphate levels of the MAS patients were significantly lower than those observed in normal controls. Plasma FGF-23 levels showed significant negative correlation with serum phosphate concentrations. In three MAS patients, pamidronate therapy decreased plasma FGF-23 levels, which showed significant negative correlation with serum 1,25(OH)(2)D concentrations. These data suggested that FGF-23 is a possible causal factor for hypophosphatemia and abnormal vitamin D metabolism in MAS.
Yamamoto
Takehisa
T
Department of Pediatrics, Minoh City Hospital, 5-7-1 Kayano, Minoh 562-8562, Japan. takehisa_yamamoto@maple.city.minoh.lg.jp
Imanishi
Yasuo
Y
Kinoshita
Eiichi
E
Nakagomi
Yoshiko
Y
Shimizu
Nobuhiko
N
Miyauchi
Akimitsu
A
Satomura
Kenichi
K
Koshiyama
Hiroyuki
H
Inaba
Masaaki
M
Nishizawa
Yoshiki
Y
Jüppner
Harald
H
Ozono
Keiichi
K
D000293:Adolescent; D000328:Adult; D002118:Calcium / Q000652:urine; D002648:Child; D004164:Diphosphonates / Q000494:pharmacology; D005260:Female; D000089703:Fibroblast Growth Factor-23; D005346:Fibroblast Growth Factors / Q000097:blood / Q000502:physiology* / Q000652:urine; D005359:Fibrous Dysplasia, Polyostotic / Q000378:metabolism*; D006801:Humans; D017674:Hypophosphatemia / Q000378:metabolism*; D007015:Hypophosphatemia, Familial / Q000378:metabolism; D000077268:Pamidronate; D014807:Vitamin D / Q000378:metabolism*
D004164:Diphosphonates; C000717427:FGF23 protein, human; D014807:Vitamin D; D005346:Fibroblast Growth Factors; D000089703:Fibroblast Growth Factor-23; D000077268:Pamidronate; D002118:Calcium