Contributor: Gordon K. Klintworth
X-linked recessive Alport syndrome accounts for the vast majority of individuals (85% of cases) with Alport syndrome. This X-linked recessive variety of Alport syndrome is due to a mutation in the COL4A5 or COL4A6 genes that encode for the alpha-5 and alpha-6 chains of collagen type IV. Abnormalities documented in X-linked Alport syndrome include anterior lenticonus [lenticonus - anterior] (25% of cases), cataracts, spontaneous lens rupture, spherophakia, posterior lenticonus, dot-and-fleck retinopathy [retinopathy - dot-and-fleck] (85% of affected adult males), poor macular relex, hyperfluorescence on fluorescein angiography, posterior polymorphous corneal dystrophy (rare), microcornea, and iris atrophy [atrophy - iris]. Other systemic manifestations include renal failure and high-tone sensorineural deafness.