Although Cx43 expression is increased in renal biopsy material from individuals with diabetic nephropathy [15], nephroangiosclerosis [24] and obstructive nephritis [14], here we provide novel evidence that GJA1 is increased in kidneys from individuals with an array of different types of CKD, and that this increased expression positively correlates with a decline in kidney function, as evidenced by increasing proteinuria and declining GFR. This evidence concerns the gene GJA1 and chronic kidney disease.