A Case of Autosomal Dominant Alport Syndrome Diagnosed Just Before Discontinuation of Follow-Up

Persistent microscopic hematuria in children is often considered benign, yet recent evidence shows that a substantial proportion of affected individuals have underlying glomerular disease, particularly collagen IV-related nephropathies. We report a case of autosomal dominant Alport syndrome (ADAS) diagnosed just before discontinuation of long-term follow-up in a young woman initially presumed to have benign familial hematuria. The proband had persistent microscopic hematuria from early childhood, with normal renal function and no extrarenal manifestations. Her mother also had microscopic hematuria without kidney impairment, and the absence of accessible family history reinforced the assumption of benign familial hematuria. At age 42, the mother developed sensorineural hearing loss, and around the same time, the family learned that the maternal grandfather was undergoing dialysis for end-stage renal disease of unknown etiology. These findings prompted genetic testing, which identified a heterozygous pathogenic COL4A4 frameshift variant (c. 2317₂318del; p. Arg773GlyfsTer14) in both the mother and the proband, confirming ADAS. This case illustrates the phenotypic variability of ADAS within a single family and highlights the limitations of relying solely on clinical features or incomplete family history. In contemporary practice, persistent glomerular hematuria warrants long-term follow-up and a low threshold for molecular testing of COL4A3-COL4A5, even in the absence of overt clinical signs. Earlier genetic evaluation would likely have enabled a timelier diagnosis in this case. This report underscores the importance of reassessing presumed benign hematuria and integrating genetic testing into the diagnostic approach for children and young adults with persistent microscopic hematuria.