The data respecting the correlation between CA9 and different types of cathepsins (CTSB, CTSD, CTSK, CTSL1, CTSL2, CTSS) were inconsistent, so we focused on the expression of CTSD in AAA tissues and revealed that 82% of CA9-positive tissues were positive for CTSD mRNA. This evidence concerns the gene CTSV and triple-A syndrome.