Functional haplotypes of the RET proto-oncogene promoter are associated with Hirschsprung disease (HSCR).
The activation of the RET signaling pathway during embryogenesis is a crucial prerequisite for a directional migration of enteric nervous system progenitor cells. Loss-of-function germline mutations of the RET proto-oncogene are reported in familial and sporadic cases of Hirschsprung disease (HSCR) with a variable frequency. Furthermore, variants of several RET polymorphisms are over- or under-represented in HSCR populations. Specifically, the c.135A RET variant has been previously shown to be strongly associated with the HSCR phenotype. We have reported an HSCR-phenotype modifying effect of the RET c.135G>A polymorphism due to a within-gene interaction in patients harboring RET germline mutations, yet the function of the c.135G>A variant is unknown. The basic RET promoter region was investigated by DNA sequencing approach in 80 HSCR patients. Identified polymorphisms were genotyped in the HSCR and in a control population and haplotypes were reconstructed. The dual-luciferase assay was used to evaluate the activity of different RET promoter haplotypes. We demonstrate that variants of two RET promoter polymorphisms -5G>A and -1C>A from the transcription start site are associated with HSCR. Furthermore, the -5G>A polymorphism is in strong linkage disequilibrium with the c.135G>A polymorphism. The promoter haplotype -5/-1AC associated with HSCR has a significantly lower activity in an in vitro dual-luciferase expression assay compared with those haplotypes identified in the majority of normal controls. These data suggest a role for RET haplotypes containing the -5A promoter variant in the etiology of HSCR.
Department of Pediatric Surgery, University of Technology Dresden, Germany. guido.fitze@mailbox.tu-dresden.de
Guido
G
Fitze
Hella
H
Appelt
Inke R
IR
König
Heike
H
Görgens
Ulrike
U
Stein
Wolfgang
W
Walther
Manfred
M
Gossen
Matthias
M
Schreiber
Andreas
A
Ziegler
Dietmar
D
Roesner
Hans K
HK
Schackert
D005260:Female; D005787:Gene Frequency; D006239:Haplotypes; D006627:Hirschsprung Disease / Q000235:genetics*; D006801:Humans; D008297:Male; D011110:Polymorphism, Genetic; D011401:Promoter Regions, Genetic; D000090063:Proto-Oncogene Mas; D011518:Proto-Oncogene Proteins / Q000235:genetics* / Q000378:metabolism; D051096:Proto-Oncogene Proteins c-ret; D020794:Receptor Protein-Tyrosine Kinases / Q000235:genetics* / Q000378:metabolism; D015398:Signal Transduction; D014407:Tumor Cells, Cultured
C000715470:MAS1 protein, human; D000090063:Proto-Oncogene Mas; D011518:Proto-Oncogene Proteins; D051096:Proto-Oncogene Proteins c-ret; D020794:Receptor Protein-Tyrosine Kinases