RESUMEN
<p><b>OBJECTIVE</b>[corrected] To investigate the mutation at the transmembrane domain of fibroblast growth factor receptor 3 (FGFR3) nucleotide 1138 site for identifying the major pathologic mechanism of achondroplasia (ACH) and to evaluate the efficacy of denaturing gradient gel electrophoresis(DGGE) method for screening the point mutations.</p><p><b>METHODS</b>The genomic DNA from 17 clinically diagnosed ACH patients where analysed by polymerase chain reaction-restriction fragment length polymorphism(PCR-RFLP) with Sfc I and Msp I restriction endonucleases and by PCR-DGGE technique for screening.</p><p><b>RESULTS</b>G to A transition mutation at nucleotide 1138 was detected in 14/17 of the ACH patients as heterozygotes by PCR-RFLP with Sfc I digestion. No 1138 G to C transition was detected by Msp I digestion. All of the 14 samples with G to A mutation were also found to be positive for point mutation by PCR-DGGE. No mutation was detected in 3 negative samples by PCR-RFLP, implying that there was actually no point mutation in this amplified region.</p><p><b>CONCLUSION</b>Nucleotide 1138 in transmembrane domain of FGFR3 gene is the hot point for mutation in ACH and hence its major pathologic cause. PCR-DGGE is a sensitive and reliable technique for point mutation screening, especially for the heterozygotes.</p>