RESUMEN
<p><b>OBJECTIVE</b>Mutation analysis and prenatal gene diagnosis for the mutated tyrosinase (TYR) gene in two families with oculocutaneous albinism type I (OCA1).</p><p><b>METHODS</b>To define the fetus genotypes and gene mutation sites, the PCR and sequencing techniques were applied to amplify and analyze the regions of exon, exon-intron and promoter of TYR gene in probands and their parents of 2 families.</p><p><b>RESULTS</b>The patient or proband of family 1 showed as a compound heterozygote with mutants R278X and 929insC. However, the fetus did not get any one of the two mutations, and so was with a normal genotype and phenotype. The parents of proband in family 2 were heterozygous with IVS4+ 3A>T or G253E respectively, but their fetus was heterozygous only with IVS4+3A>T but without G253E, and so was a carrier as his father.</p><p><b>CONCLUSION</b>In the mainland of China, the prenatal gene diagnosis of OCA1 is reported for the first time.</p>