Several rare electrophoretic variants of red cell catalase were identified by Baur (1963). Nance et al. (1968) also described electrophoretic variants. Data on gene frequencies of allelic variants were tabulated by Roychoudhury and Nei (1988).Wieacker et al. (1980) assigned a gene for catalase to 11p by study of man-mouse cell hybrid clones. In the hybrid cells, detection of human catalase was precluded by the complexity of the electrophoretic patterns resulting from interference by a catalase-modifying enzyme activity. Therefore, a specific antihuman antibody was used in conjunction with electrophoresis. In mouse, catalase is not syntenic to the beta-globin cluster or to LDH-A. Junien et al. (1980) investigated catalase gene dosage effects in a case of 11p13 deletion, a case of trisomy of all of 11p except 11p13, and a case of trisomy 11p13. The results were consistent with assignment of the catalase locus to 11p13 and its linkage with the WAGR complex (194070). Assay of catalase activity should be useful in identifying those cases of presumed new mutation aniridia that have a risk of Wilms tumor or gonadoblastoma, even in the absence of visible chromosomal deletion. In karyotypically normal ...