HSPG2 and Balkan nephropathy: Figure 3 represents the distribution of the three mutant genes in all BEN patients. KCNK5 variant c.1397A>C occurs only in combination with one or two of the other variants (HSPG2 c.5239A>C and CELA1 c.9_10delC), while CELA1 variant is present as a single aberration in 6 out of 10 positive cases.