CYP3A4*18 Allele

**Semantic type:** Gene or Genome

**Definition:** Human CYP3A4*18 allele is located in the vicinity of 7q21.1 and is approximately 27 kb in length. This allele, a variant form of the CYP3A4 wild-type allele, encodes cytochrome P450 3A4*18 protein. The CYP3A4*18 allele exhibits a clinically-relevant SNP (g.20070T>C) in exon 10 that results in a L293P coding change. This alteration in protein sequence dramatically increases the enzymatic activity of the cytochrome P450 3A4*18 protein.

**Synonyms:** - CYP3A4*18 - CYP3A4, L293P - CYP3A4, g.20070T>C - Cytochrome P450, Family 3, Subfamily A, Polypeptide 4*18 Allele