Noninvasive optical coherence tomography biomarker for Alport syndrome, COL4-related focal segmental glomerulosclerosis, and COL4 variant interpretation.

Temporal Thinning Index Maximum stratified disease severity across genotypes (severe X-linked alport syndrome-Male/autosomal recessive alport syndrome: 11.8%; intermediate X-linked alport syndrome-Female/autosomal dominant alport syndrome: 7.3-8.1%; controls: 5.3-5.8%) and remained significantly associated with disease severity after adjustment for age, eGFR, and blood pressure.

Temporal Thinning Index Maximum distinguished severe alport syndrome from primary immune-mediated focal segmental glomerulosclerosis (focal segmental glomerulosclerosis) (AUC 0.97;0.94-1.00) and differentiated COL4A-related focal segmental glomerulosclerosis from primary focal segmental glomerulosclerosis (AUC 0.91; 0.77-1.00).