They conducted a study on 157 adults with pathogenic or likely pathogenic variants in the COL4A3 or COL4A4 genes and found that 53.5% had at least one kidney cyst (1+ KC) in either kidney, and 28.0% had three or more kidney cysts (3+ KCs) in either kidney. Here, COL4A4 is linked to Complex Cyst of Kidney.