Six distinct genes have been identified as belonging to the type IV collagen gene family. They can be organized into three sets, i.e., @entity5938 / @entity12580 , @entity19787 / @entity13999 , and @entity3687 / @entity42442 , which are localized on three different chromosomes in @entity1 , 13, 2, and X, respectively. Within each set the genes are aligned head-to-head and their expression is regulated by bidirectional promoters between the genes. Transcriptional regulation of the @entity5938 / @entity12580 set has been well characterized. The transcription of @entity42442 seems to be controlled by two alternative promoters. While collagen IV molecules composed of @entity6927 chains are broadly distributed, molecules comprising combinations of the other four chains, alpha3-alpha6, are important components of specialized basement membranes. The precise chain composition of triple-helical molecules assembled from the alpha3-alpha6 chains is not entirely clear, but it is hypothesized that alpha3-alpha5 chains and alpha5 and alpha6 chains form heterotrimeric molecules. Several pieces of evidence indicate that alpha3/alpha4/alpha5 molecules and alpha5/alpha6 molecules are components of the basement membrane network. This helps explain the observation that the kidney and skin basement membranes from @entity1 with @entity3686 caused by mutations in the alpha5 coding gene, @entity3687 , are defective in the alpha3, @entity1293 chains together with the alpha5 chain. Large deletions involving the @entity3687 and @entity42442 genes have been found in rare cases of @entity32355 associated with @entity3686 .

Organization and expression of basement membrane collagen IV genes and their roles in XXXX disorders.

@entity1 :: ('9606', 'Species') :: ['humans', 'patients'] @entity3686 :: ('MESH:D009394', 'Disease') :: ['Alport syndrome'] @entity19787 :: ('1285', 'Gene') :: ['COL4A3'] @entity3687 :: ('1287', 'Gene') :: ['COL4A5'] @entity32355 :: ('MESH:C537113', 'Disease') :: ['diffuse leiomyomatosis'] @entity13999 :: ('1286', 'Gene') :: ['COL4A4'] @entity5938 :: ('1282', 'Gene') :: ['COL4A1'] @entity42442 :: ('1288', 'Gene') :: ['COL4A6'] @entity1293 :: ('3476', 'Gene') :: ['alpha4, and alpha6'] @entity12580 :: ('1284', 'Gene') :: ['COL4A2'] @entity6927 :: ('146', 'Gene') :: ['alpha1 and alpha2']
@entity1 :: (9606,Species) :: ['human']
