Alport syndrome (AS) is a familial hereditary nephropathy which is characterized by molecular abnormalities in Collagen IV a345. As more gene mutations are discovered, it has been reported that autosomal recessive disease accounts for a smaller proportion (about 4%) of AS patients than previously recognized. We report here a novel mutation in COL4A4 in a Chinese family with autosomal recessive AS. Patient 1 was a 24-year-old Chinese man. He and his brother (patient 2) had a history of proteinuria and hematuria with renal dysfunction and sensorineural deafness. Pathologic findings were consistent with Alport syndrome, and genetic analysis revealed that both patients had two heterozygous mutations, c.1423 G>T (p.Gly475Cys) in EX21/CDS20 and c.735 G>A (p.Pro245Pro) in EX12/CDS11, and that each mutation originated from their mother or father who were carriers for one of these two mutations. Both patients showed similar results by laboratory examination and histopathologic assessment. Patient 1 received ACEI treatment and ran a stable clinical course, whereas patient 2 refused ACEI treatment and had progressive deterioration of renal function. This is the first report of a novel mutation in the collagen domain of COL4A4 gene. The results add to the spectrum of mutations in COL4A4 of Alport syndrome.
Keywords: Alport syndrome; COL4A4 mutation; autosomal recessive.
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