We describe a novel mutational study in 2 African American siblings with autosomal recessive Alport syndrome. Both siblings were compound heterozygotes for 2 abnormal DNA sequences in exon 49 of the COL4A3 gene, p.Arg1496X (CGA-->TGA) and p.Arg1516X (CGA-->TGA). These are nonsense mutations in the noncollagenous domain resulting in premature termination codons and have not been previously reported. In an African American population in which autosomal recessive Alport syndrome is rarely seen, complete sequencing of the COL4A3 and COL4A4 genes may be necessary to identify the underlying mutation and confirm the diagnosis.