Phenotype presentation of hypophosphatemic rickets in adults.
Hypophosphatemic rickets (HR) is a group of rare disorders caused by excessive renal phosphate wasting. The purpose of this cross-sectional study of 38 HR patients was to characterize the phenotype of adult HR patients. Moreover, skeletal and endodontic severity scores were defined to assess possible gender differences in disease severity in patients with genetically verified X-linked HR. Compared to normal reference data, i.e., z = 0, HR patients had significantly lower final height, with a mean difference in z-score of -1.9 (95% CI -2.4 to -1.4, P < 0.001). Compared to paired z-scores of final height, z-scores of leg length were significantly lower and those of sitting height were significantly higher (P < 0.001), resulting in disproportion as indicated by the significantly elevated sitting height ratio, mean difference in z-score of 2.6 (95% CI 2.1-3.1, P < 0.001). Z-scores of head circumference (median 1.4, range -0.4 to 5.5, P < 0.001) and z-scores of bone mineral density (BMD) of the lumbar spine (median 1.9, range -1.5 to 8.6, P < 0.001) were significantly elevated compared to normal reference data. The relative risk (RR) of fracture was reduced (RR = 0.34, 95% CI 0.20-0.57, P < 0.001). The skeletal severity score tended to be higher in males compared to females (P = 0.07), and no gender difference in endodontic severity was found. In conclusion, adult HR patients were characterized by short stature and were disproportioned. They had elevated BMD of the lumbar spine and a reduced risk of fractures. We found a tendency for males to be more severely affected than females.
Department of Pediatrics, H. C. Andersen Children's Hospital, Odense University Hospital, Sdr. Boulevard 29, 5000 Odense, Denmark. sbeck-nielsen@dadlnet.dk
Signe S
SS
Beck-Nielsen
Klaus
K
Brusgaard
Lars M
LM
Rasmussen
Kim
K
Brixen
Bendt
B
Brock-Jacobsen
Mette R
MR
Poulsen
Peter
P
Vestergaard
Stuart H
SH
Ralston
Omar M E
OM
Albagha
Sven
S
Poulsen
Dorte
D
Haubek
Hans
H
Gjørup
Hanne
H
Hintze
Mette G
MG
Andersen
Lene
L
Heickendorff
Jacob
J
Hjelmborg
Jeppe
J
Gram
D000328:Adult; D001827:Body Height / Q000502:physiology; D015519:Bone Density / Q000502:physiology; D003430:Cross-Sectional Studies; D053098:Familial Hypophosphatemic Rickets / Q000175:diagnosis* / Q000235:genetics / Q000503:physiopathology; D005260:Female; D000089703:Fibroblast Growth Factor-23; D005346:Fibroblast Growth Factors / Q000097:blood / Q000235:genetics; D050723:Fractures, Bone / Q000453:epidemiology; D040181:Genetic Diseases, X-Linked; D006801:Humans; D008159:Lumbar Vertebrae / Q000000981:diagnostic imaging; D008297:Male; D010018:Osteomalacia / Q000503:physiopathology; D053402:PHEX Phosphate Regulating Neutral Endopeptidase / Q000235:genetics; D010510:Periodontal Diseases / Q000453:epidemiology; D010641:Phenotype; D011859:Radiography; D012016:Reference Values; D012307:Risk Factors; D012720:Severity of Illness Index; D012727:Sex Characteristics; D019553:Tooth, Nonvital / Q000453:epidemiology*
D005346:Fibroblast Growth Factors; D000089703:Fibroblast Growth Factor-23; D053402:PHEX Phosphate Regulating Neutral Endopeptidase; C506231:PHEX protein, human