RET 3'UTR polymorphisms and its protective role in Hirschsprung disease in southeastern Chinese

Background: Hirschsprung disease (HSCR) is a complex congenital disorder characterized by intestinal obstructions owing to the absence of the intestinal ganglion cells of the nerve plexuses in variable lengths of the digestive tract. Several RET polymorphisms and haplotypes have been described as underrepresented in HSCR patients with respect to controls. We thus sought to investigate whether polymorphisms in RET 3'UTR are associated with isolated HSCR in the Chinese population.

Methods: Polymerase chain reaction amplification and direct sequencing were used to screen polymorphisms in RET 3'UTR in patients with sporadic HSCR and ethnically matched controls in Han Chinese populations. Association tests of RET 3'UTR variants and haplotypes with HSCR were performed.

Results: We examined a total of 107 Chinese sporadic HSCR patients and 89 ethnically matched controls by sequencing the 3'UTR of the RET gene. Five single nucleotide polymorphisms (SNPs) and 2 monomorphic SNPs were identified. The genotype distributions and the allele frequencies of the 5 SNPs were significantly different between HSCR cases and controls and occurred more frequently in the control population. Haplotype analysis has shown a higher frequency of haplotypes comprising variant alleles in controls as compared with cases.

Conclusions: The significant deviations of the genotype distributions and the allele frequencies of these SNPs in the HSCR population compared with the control population demonstrate that these SNPs have a strong negative association with HSCR and could act as protective alleles.