Genetic diagnosis strategy of hereditary non-polyposis colorectal cancer

Table 1 Detection results in 30 probands from HNPCC families

Family	Bethesda guidelines	MSI	Expression of MMR proteins		Micromutation/polymorphism2/large fragment deletion	hMLH1 gene promoter methylation
			MSH2	MLH1
H1	BG1	MSI-H	+	+		u
H4	BG1	MSI-H	-	+	hMSH2 exon13 IVS13-2 A→C (SA of Exon 14)	u
H9	BG1	MSI-H	-	+	hMSH2 exon3 c.610G→T (G204stop)	u
H17	BG1	MSI-H	+	+	hMSH2 exon5 c.899_890insAT1	u
H22	BG1	MSI-H	-	+	hMSH2 exon7 IVS7-1G→A (SA of Exon 8)1	u
H10	BG1	MSI-H	+	+	hMSH2 exon15 c.2583A→G (Q861Q)12	u
H2	BG1	MSI-H	-	+	hMSH2 exon8 deletion	u
H5	BG1	MSI-H	-	+		u
H11	BG3	MSI-H	-	+		u
H23	BG1	MSI-H	-	+	hMSH2 exon1-6 deletion	u
H25	BG3	MSI-H	-	+		u
H13	BG1	MSI-H	-	+	hMSH2 exon 7 c.1231 insertion T shift	u
H34	BG4	MSI-H	-	+	hMSH2 exon1-7 deletion	u
H3	BG1	MSI-H	+	-	hMLH1 exon18 c.2041G→A (A681T)	u
H12	BG3	MSI-H	+	-	hMLH1 exon15 IVS15+1 G→A (SD of Exon 15)	u
H19	BG1	MSI-H	+	-	hMLH1 exon8 c.677G→A (splice site mutation)	u
H20	BG1	MSI-H	+	-	hMLH1 exon8 c.677G→A (splice site mutation)	u
H21	BG1	MSI-H	+	-	hMLH1 exon19 c.2141G→A (W714stop)	u
H28	BG1	MSI-H	+	-	hMLH1 exon8 c.655A→G (I219V)	m
H29	BG1	MSI-H	+	-	hMLH1 exon6 c.503_4insA1	u
H30	BG1	MSI-H	+	-	hMLH1 exon9 IVS9+1 G→A (SD of Exon 9)	u
H14	BG1	MSI-H	+	-		u
H18	BG1	MSI-H	+	-		u
H33	BG3	MSI-H	+	-		u
H35	BG3	MSI-H	+	-	hMLH1 exon17 c.1930 del G	u
H8	BG4	MSI-L	+	+		m
H6	BG3	MSS	+	+		m
H36	BG1	MSS	+	+		u
H15	BG3	MSS	+	+		u
H27	BG1	MSS	+	+		u

+: Expression; -: Deletion;

¹Novel mutation discovered;

²Polymorphism; m: Methylation; u: Non-methylation; MSI-H: High frequency microsatellite instability; MSI-L: Low frequency microsatellite instability; MSS: Mcrosatellite stability.