Specific biochemical markers of bone metabolism and cytokine study confirm the diagnosis of malignant infantile osteopetrosis at birth using cord blood sample.
OBJECTIVE
To investigate the serum creatine kinase isoenzyme pattern, specific biochemical markers of bone metabolism, and cytokines in a Chinese family with osteopetrosis, and correlate abnormalities with the pathophysiology of this condition.


METHODS
A Chinese female baby was diagnosed with malignant infantile osteopetrosis at the age of 3 weeks by clinical history and biochemical investigations. We studied the laboratory and radiological manifestations of this index case and her family members.


RESULTS
Serum CK-BB fraction of our index patient was elevated to 18.0% (normal 1.6-7.6%). Her biochemical markers of bone resorption including serum C-terminal telopeptide concentration and urine N-terminal telopeptide to creatinine ratio were decreased to 0.54 microg/L (normal 0.72-1.56 microg/L) and 159 x 10(-6) (normal 372-900 x 10(-6)), respectively. Serum cytokines including soluble receptor activator of nuclear factor kappa-B ligand (sRANKL) concentration was suppressed to 0.11 pmol/L (normal 0.23-0.82 pmol/L) and osteoprotegerin (OPG) concentration was 4.9 pmol/L (normal 2.8-4.9 pmol/L), resulting in an elevated OPG to sRANKL ratio of 44.5 (normal 3.8-19.4) in favour of bone formation.


CONCLUSIONS
If left untreated, this condition is usually fatal within the first year of life. With early diagnosis, management including bone marrow transplantation can be planned ahead and will result in a better survival.
Chan
Michael H M
MH
Department of Chemical Pathology, The Chinese University of Hong Kong, Prince of Wales Hospital, Hong Kong.
Wong
K
K
Chan
Iris H S
IH
Luo
Y F
YF
Tam
Sidney
S
Lam
Christopher W K
CW
D000328:Adult; D015415:Biomarkers; D016026:Bone Marrow Transplantation; D001842:Bone and Bones / Q000378:metabolism*; D002352:Carrier Proteins / Q000097:blood; D002681:China; D003402:Creatine Kinase / Q000097:blood*; D016207:Cytokines; D005260:Female; D005312:Fetal Blood; D006023:Glycoproteins / Q000097:blood; D006801:Humans; D007231:Infant, Newborn; D007527:Isoenzymes / Q000097:blood*; D008297:Male; D008562:Membrane Glycoproteins / Q000097:blood; D010022:Osteopetrosis / Q000097:blood* / Q000175:diagnosis* / Q000628:therapy; D053244:Osteoprotegerin; D053245:RANK Ligand; D053246:Receptor Activator of Nuclear Factor-kappa B; D018160:Receptors, Cytoplasmic and Nuclear / Q000097:blood; D018124:Receptors, Tumor Necrosis Factor
D015415:Biomarkers; D002352:Carrier Proteins; D016207:Cytokines; D006023:Glycoproteins; D007527:Isoenzymes; D008562:Membrane Glycoproteins; D053244:Osteoprotegerin; D053245:RANK Ligand; D053246:Receptor Activator of Nuclear Factor-kappa B; D018160:Receptors, Cytoplasmic and Nuclear; D018124:Receptors, Tumor Necrosis Factor; C505686:TNFRSF11A protein, human; C506030:TNFRSF11B protein, human; C505688:TNFSF11 protein, human; D003402:Creatine Kinase