Elevated parathyroid hormone 44-68 and osteoarticular changes in patients with genetic hemochromatosis.

OBJECTIVE

To determine whether the osteoarticular changes associated with genetic hemochromatosis could be explained by metabolic parathyroid hormone (PTH) disorders.

METHODS

The study involved 210 patients with liver iron overload syndromes. Osteoarticular changes were numerically scored as the number of damaged joints. PTH 1-84 and 44-68 were assayed.

RESULTS

An increase in serum PTH 44-68 levels was found in one-third of untreated patients who had no calcium or PTH 1-84 abnormalities. Serum PTH 44-68 levels correlated positively with serum ferritin levels. In multivariate analyses, the number of affected joints correlated positively with age, serum PTH 44-68 levels, and serum ferritin levels.

CONCLUSION

Liver iron overload syndromes, especially genetic hemochromatosis, are associated with elevated circulating levels of PTH fragments containing the 44-68 region, which appears to play a role in osteoarticular changes. This increase seems to be a consequence of iron overload.