Aim: To investigate the pathogenic mechanism of Hirschsprung's disease (HD) at the molecular level and to elucidate the relationship between RET oncogene and Chinese patients with HD.
Methods: Exon 13 of RET oncogene from 20 unrelated HD patients was analyzed with polymerase chain reaction-single strand conformation polymorphism (PCR-SSCP). The positive amplifying products were then sequenced. According to the results of SSCP and DNA sequence, SSCP was done as well for the samples from the family other members of some cases with mutated RET gene.
Results: SSCP analysis indicated that mobility abnormality existed in 4 unrelated HD patients. Direct DNA sequence analysis identified a missense mutation, T to G at the nucleotide 18 888 and a frameshift mutation at the nucleotide 18 926 insG. In a HD family, the sicked child and his father were the same heterozygous missense mutation (T to G at nucleotide 18 888).
Conclusion: Among Chinese HD patients, RET gene mutations may exist in considerable proportion with different patterns. These new discoveries indicate that RET mutations may play an important role in the pathogenesis of unrelated HD in the Chinese population. PCR-SSCP combined with DNA sequence can be used as a tool in the genetic diagnosis of HD.