Overall the mean age at onset of end-stage renal failure was not different for individuals with COL4A3 (23.2 + 9.3, years, 95% CI 20.1 to 26.5) or COL4A4 mutations (mean 25.4 ±10.3 years, 95% CI 21.3 to 29.6) compared with COL4A5 mutations (24.4 ± 7.8 years, 95% CI 23.4 to 25.4, n = 237) (Table 4). The gene discussed is COL4A4; the disease is stage 5 chronic kidney disease.