Genetic risks and familial associations of small bowel carcinoma

Table 1 Genetic risks and familial associations of small bowel carcinoma

Syndrome	Mode of inheritance	Mutated/associated gene	Relative risk (95%CI)	Lifetime risk for SBA	Polyps/pathway
FAP[7,29]	Autosomal dominant (AD)	APC	330 (132-681)	3%-5%	Adenoma-carcinoma
HNPCC/LS[13,14,29]	AD	MMR (MSH2, MSH6, MLH1 ,PMS2)	291 (71-681)	1%-4%	Adenoma-carcinoma
PJS[31,36,37]	AD	STK11	500 (220-1306)	1.7%-13%	Hamartoma, adenoma-Ca
JPS[38,41]	AD	BMPR1A, SMAD4	Unknown	Unknown	Hamartoma, adenoma-Ca
Crohn’s disease	Unknown (genome wide studies have associated 140 loci)	Unknown	30-60[44-49] (15-609)	2.2% after/25 yr	Dysplasia- carcinoma
Celiac disease	Association with HLA-DQ2,HLA-DQ8	Unknown	60-80[61-63] (7-240)	< 1%	Adenoma-carcinoma

FAP: Familial adenomatous polyposis; APC: Adenomatous polyposis coli; HNPCC: Hereditary nonpolyposis colorectal cancer; MMR: Mismatch repair gene; LS: Lynch syndrome; PJS: Peutz-Jeghers syndrome; STK11: Serine threonine kinase; JPS: Juvenile polyposis syndrome; BMPRIA: Bone morphogenetic protein receptor, type IA; SMAD4: Mothers against decapentaplegic homolog; HLA: Human leukocyte antigen complex.