Pediatric hematuria as a gateway to family genetic investigation in type IV collagen nephropathies: experience from a regional cohort.

Pathogenic variants in COL4A4 and COL4A3 were detected in one patient each, while two patients harbored only COL4A3 variants of uncertain significance.

Glycine-substituting missense variants were the most frequent molecular defect (9/18 cases), whereas loss-of-function variants were identified in 7/18 patients, including variants in COL4A5, COL4A3 and COL4A4.

Proteinuria was present in 44% of patients, while kidney function was preserved at diagnosis.

A positive family history of kidney disease or hematuria was present in 61% of families, and kidney failure in adult relatives in 28%.