Urinary excretion of galactosyl-hydroxylysine is a marker of growth in children.
Galactosyl-hydroxylysine (Gal-Hyl) is the predominant product of the posttranslational glycosylation of skeletal collagen. Urinary Gal-Hyl excretion is regarded as a marker of bone resorption in adults, but little information is available on the validity of this parameter in pediatric age groups. Using 24-h urine samples from 88 healthy children and adolescents ages 4-18 yr, reference ranges were established for this age group, and values were compared with measurements in children with overt GH deficiency (n = 14) or Ullrich-Turner syndrome (n = 21). When expressed relative to body weight (Gal-Hyl/wt), urinary Gal-Hyl excretion was 3.2 to 4.7 times higher in subjects 4-16 yr of age than in adults. Highest values were observed in very young children and during the pubertal growth spurt. In the total population, urinary Gal-Hyl/wt was closely related to growth velocity (r = 0.72) and significantly correlated with the urinary excretion of both hydroxyproline (r = 0.74) and deoxypyridinoline (r = 0.88; P < 0.001 each). Urinary Gal-Hyl/wt was significantly lower in children with GH deficiency or Ullrich-Turner syndrome than in healthy children (P < 0.001 each). The urinary excretion of Gal-Hyl was significantly correlated with growth velocity in GH-deficient children (r = 0.69; P = 0.004) but not in patients with Ullrich-Turner syndrome. In the latter, the increase in urinary Gal-Hyl excretion after 3 months of treatment with recombinant human GH correlated significantly with the increase in growth velocity after 12 months of treatment (r = 0.76; P = 0.002). We conclude that the urinary excretion of Gal-Hyl is a valid and potentially useful index of skeletal growth in children.
Rauch
F
F
Childrens' Hospital, University of Cologne, Germany.
Schnabel
D
D
Seibel
M J
MJ
Remer
T
T
Stabrey
A
A
Michalk
D
D
Schönau
E
E
D000293:Adolescent; D000328:Adult; D000375:Aging / Q000652:urine; D000596:Amino Acids / Q000652:urine; D015415:Biomarkers; D001862:Bone Resorption / Q000652:urine; D002648:Child; D002657:Child Development; D002675:Child, Preschool; D005260:Female; D006130:Growth Disorders / Q000188:drug therapy / Q000652:urine; D013006:Growth Hormone / Q000627:therapeutic use / Q000652:urine; D006801:Humans; D006901:Hydroxylysine / Q000031:analogs & derivatives* / Q000652:urine; D006909:Hydroxyproline / Q000652:urine; D008297:Male; D011994:Recombinant Proteins; D012016:Reference Values
D000596:Amino Acids; D015415:Biomarkers; D011994:Recombinant Proteins; D006901:Hydroxylysine; C007817:galactosylhydroxylysine; D013006:Growth Hormone; C036020:deoxypyridinoline; D006909:Hydroxyproline