Is deoxypyridinoline a good resorption marker to detect osteopenia in phenylketonuria?
OBJECTIVE
To evaluate deoxypyridinoline as a resorption marker in phenylketonuria (PKU) and to search for a relationship between deoxypyridinoline, calcium/creatinine index (Ca/Cr I), osteocalcin and bone alkaline phosphatase (BAP).


METHODS
This was a transversal analytical study of 46 PKU patients [17.5 (4-38) years]. Deoxypyridinoline and osteocalcin were measured with a chemiluminescent assay and BAP was measured with an immunoradiometric assay.


RESULTS
Deoxypyridinoline was significantly increased in patients aged 7-14 and >18 years old, being associated with age (r=-0.724, P<0.001). Adult patients showed significantly higher Ca/Cr I, which correlates with Phe values for the year prior to the study (P=0.014). Serum BAP was significantly increased in pediatric patients (9-13 years), while it was decreased in adult patients (P=0.003). Decreased osteocalcin levels were found in patients>15 years (P=0.028). Altered deoxypyridinoline and BAP values were related (P=0.042).


CONCLUSIONS
PKU patients excreted increased D-Pyr, suggesting high bone resorption. Bone formation seems active in childhood but deteriorates in adult PKU patients. Periodic measurement of D-Pyr and BAP may be useful in the prevention of osteopenia in PKU patients.
Millet
Pablo
P
PKU-follow-up Unit: Department of Biochemistry, Hospital Sant Joan de Déu, Universitat de Barcelona, Barcelona, Spain.
Vilaseca
M Antonia
MA
Valls
Carme
C
Pérez-Dueñas
Belén
B
Artuch
Rafael
R
Gómez
Lilian
L
Lambruschini
Nilo
N
Campistol
Jaume
J
D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000469:Alkaline Phosphatase / Q000097:blood; D000596:Amino Acids / Q000652:urine*; D015415:Biomarkers / Q000097:blood / Q000652:urine; D001851:Bone Diseases, Metabolic / Q000097:blood* / Q000150:complications / Q000175:diagnosis*; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D015592:Immunoradiometric Assay / Q000379:methods; D008163:Luminescent Measurements; D008297:Male; D015675:Osteocalcin / Q000097:blood; D010661:Phenylketonurias / Q000097:blood* / Q000150:complications
D000596:Amino Acids; D015415:Biomarkers; D015675:Osteocalcin; C036020:deoxypyridinoline; D000469:Alkaline Phosphatase