RESUMEN
<p><b>OBJECTIVE</b>To investigate the mutations of phenylalanine hydroxylase (PAH) gene in 20 phenylketonuria (PKU) patients from Yunnan.</p><p><b>METHODS</b>The 13 exons and the splicing regions of 12 introns of the PAH gene were sequenced to detect mutations in 20 unrelated PKU patients.</p><p><b>RESULTS</b>PAH gene sequencing has revealed 15 types of mutations, in which the most frequently mutation was p.R243Q (30.0%), followed by p.Y356X(10.0%), p.R111X (7.5%), IVS4+2T>A (7.5%) and p.V399V (7.5%). Exons 7, 11, 3 and introns 4, 11 were most frequently involved. Six novel mutations, including c.59A>C, c.60G>C, c.690_691insG, c.1119_1120insT, c.441+2T>A, c.842+4A>T and c.1200+1T>G were detected.</p><p><b>CONCLUSION</b>PAH gene mutations identified in Yunnan are more similar to those of northern China, with R243R being the most common, though there are still certain characteristics for the type and frequency of mutations.</p>