COL4A4 and Alport syndrome: Due to the various ways of identifying patients with heterozygous P/LP COL4A3 or COL4A4 variants, several diagnostic labels are (or have been) used, including ‘thin basement membrane nephropathy’, ‘autosomal dominant Alport syndrome’, ‘Type IV collagen-associated kidney disease’, ‘Alport spectrum nephropathy’ and, historically, ‘benign familial haematuria’.