DNA sequencing analysis in 4 patients in exon 4 of CYP 2C9.

Heterozygosities (shown by the presence of double peaking) were observed in codons 181, 184, 192, and 208, resulting in polymorphic alleles of 527ATT>CTT (Ile181Leu), 537CAT>CCT (His184Pro), 561CAG>CCG (Gln192Pro), and 608TTG>GTG (Leu208Val).