Background. In primary hyperoxaluria type I (PH 1), hepatic overproduction
of oxalate leads to its deposition in various organ systems including bone
(oxalosis). To evaluate skeletal status non-invasively in PH 1 we measured
bone mineral density (BMD).
Methods. Peripheral quantitative computed tomography of the distal radius w
as performed in 10 children with PH 1 (mean chronological age 9 +/- 3.1, me
an skeletal age 8.3 +/- 3.0 years): seven were on conservative treatment (C
T) including one patient after pre-emptive liver transplantation (PH1-CT) a
nd three were studied with end-stage renal disease on peritoneal dialysis (
PH1-ESRD).
Results. Mean trabecular bone density (TBD) was significantly increased in
PH1-ESRD compared with both age-matched healthy and uraemic controls (65227
vs 168 +/- 63 and 256 +/- 80 mg/cm(3); P < 0.002 and P < 0.007, respective
ly). while cortical bone density (CBD) was elevated to a lesser degree (517
+/- 23 vs 348 +/- 81 vs 385 +/- 113 mg/cm(3); P < 0.02 and P < 0.04, respe
ctively). In PH 1, CBD and. even more so, TBD were significantly correlated
with serum creatinine (r = 0.91 and r = 0.96, P < 0.0001, respectively) an
d plasma oxalate levels (r = 0.86 and r = 0.94. P < 0.001 and P < 0.0001. r
espectively). In children with PH 1 and normal glomerular function, both CB
D and TBD were comparable with healthy controls.
Conclusion. These preliminary data suggest that in PH 1 BMD is significantl
y increased in ESRD. probably due to oxalate disposal. Measurement of BMD m
ay be a valuable and non-invasive tool in determining and monitoring oxalat
e burden in this disorder.