At the time of this study, there were five known patients with Wilson disease (WD) in Iceland. The mutation, a 7-bp deletion in exon 7 on chromosome 13 for WD, is only known in Iceland. In twenty healthy Icelandic heterozygotes for WD and their age- and gender-matched controls, copper concentration in plasma, ceruloplasmin (CP) concentration, CP oxidative activity and CP-specific oxidative activity in serum and superoxide dismutase (SOD1) activity in erythrocytes were determined. The same determinations were done on the five WD patients. There was no significant difference in these parameters between the heterozygotes and the controls, although an inclination toward lower CP determinations and higher SOD1 activity in the heterozygotes was noted. As expected the WD patients were low on the copper and CP parameters, but their SOD1 activity was within the upper normal range. In conclusion, the CP parameters and SOD1 activity are within the normal range in Icelandic heterozygotes for WD, although with a trend toward mild dyshomeostasis. This may indicate subclinical copper retention in the heterozygotes, but a bigger study group is needed to confirm this.
Keywords: SOD1; Wilson disease; ceruloplasmin; heterozygotes.