Mapping Data

Experiment

• Experiment
  TEXT-QTL
• Chromosome
  9
• Reference
  J:84661 Kozaiwa K, et al., Identification of a quantitative trait locus for ileitis in a spontaneous mouse model of Crohn's disease: SAMP1/YitFc. Gastroenterology. 2003 Aug;125(2):477-90
• ID
  MGI:3574490

Genes

Gene	Assay Type
Ibdq1	resistance/susceptibility
D9Mit297	PCR
D9Mit123	PCR
D9Mit48	PCR
Il10ra	reported elsewhere
Il18	reported elsewhere

Notes

• Experiment
  Inbred strain SAMP1/YitFc develops spontaneous ileitis and is considered a mouse model for Crohn's disease-like inflammatory bowel disease (IBD). (SAMP1/YitFc is originally derived from AKR/J and an unknown mouse strain.) By 30 weeks of age 100% of male and female SAMP1/YitFc animals develop ileitis. Linkage analysis was performed on 150 (C57BL/6J x SAMP1/YitFc)F2 intercross animals to identify QTLs associated with IBD. 103 polymorphic markers were used in the genome scan.
  
  Linkage to total inflammatory score and epithelial changes mapped to an interval on mouse Chromosome 9 between D9Mit297 (15 cM) and D9Mit123 (42 cM). Peak linkage occurs at D9Mit48 (34 cM) with LOD=3.1 for degree of epithelial changes. This locus is named Ibdq1 (inflammatory bowel disease QTL 1). SAMP1/YitFc-derived alleles confer susceptibility to IBD with an additive mode of inheritance. Two possible candidate genes that map to this interval are Il10ra (26 cM) and Il18 (29 cM). Both of these genes show involvement in mouse or human IBD. However, sequence analysis of the coding region of Il10ra and Il18 did not reveal any polymorphisms between SAMP1/YitFc, C57BL/6J, or AKR/J. There is evidence this region of the mouse genome may be derived from AKR/J. A previously identified colitis QTL named Tnbs1 (48 cM) maps to the Ibdq1 interval. The Ibdq1 interval also overlaps with a NON/Lt-derived colitis resistance locus identified in a congenic strain by Mahler et al, 1999.
  
  Suggestive linkage to total inflammatory score mapped to an interval on mouse Chromosome 6 between D6Mit243 (30.4 cM) and D6Mit39 (46.3 cM).
  
  Suggestive linkage to total inflammatory score mapped to mouse Chromosome X at DXMit117 (50.8 cM).
  
  The combined effect of Ibdq1 and the loci on chromosome 6 and chromosome X explains 21% of the phenotypic variance for epithelial changes.