Ibdq1^SAMP1/YitFcs
QTL Variant Detail

Summary

• QTL variant: Ibdq1^SAMP1/YitFcs
• Name: inflammatory bowel disease QTL 1; SAMP1/YitFcs
• MGI ID: MGI:3574494
• QTL: Ibdq1 Location: Chr9:33978840-73439255 bp Genetic Position: Chr9, cM position of peak correlated region/allele: 31.63 cM
• QTL Note: genome coordinates based on the marker associated with the peak LOD score

Variant origin

• Strain of Specimen: SAMP1/YitFcs

Variant description

• Allele Type: QTL
• Mutation: Undefined
• This allele confers susceptibility to inflammatory bowel disease compared to C57BL/6J. (J:84661)
• Inheritance: Other (see notes)

Expression

In Structures Affected by this Mutation:

1 anatomical structure(s)

Notes

Ibdq1 exhibits additive inheritance. This allele affects the degree of epithelial changes in the ileum and total inflammatory score.

Mapping and Phenotype information for this QTL, its variants and associated markers

J:84661

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.

References

• Original: 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
• All: 2 reference(s)