Table 3.

Hereditary non-polyposis colorectal cancer (HNPCC) suspected families with mutation in hMLH1 or hMSH2

Category	Patient No	Family No	Gene	Exon	Base change	Base No	Codon	AA change	MSI	Comment
1	1	1	MLH1	11	Del G	1046	349	Frameshift	MSI-H	Stop codon 380
Amsterdam	2	1	MLH1	11	Del G	1046	349	Frameshift	MSI-H	Stop codon 380
criteria I	3	2	MLH1	16	Del AAG	1846–8	616	Del Lys	MSI-H	Pathogenic, see text
	4	3	MSH2	12	Del AAT	1786–8	596	Del Asn	MSI-H	Pathogenic, see text
	5	4	MSH2	11	T>A	2 bases downstream	—	Splice mutation	MSI-H	Pathogenic, see text
2	12	11	MLH1	1	C>T	76	26	Gln>stop	MSI-H	Stop codon
Amsterdam	13	12	MSH2	12	Del AAT	1786–8	596	Del Asn	MSI-H	Pathogenic, see text
criteria II	16	4	MSH2	11	T>A	2 bases downstream	—	Splice mutation	MSI-H	Pathogenic, see text
6*	37	34	MSH2	12	Del AAT	1786–8	596	Del Asn	MSI-H	Pathogenic, see text
7*	42	39	MSH2	12	Del AAT	1786–8	596	Del Asn	MSI-H	Pathogenic, see text

*Category 6, proband at age 40 years or younger with at least one CRC among family members; category 7, both proband and one first degree relative with CRC <55 years.

MSI, microsatellite instability; MSI-H, high microsatellite instability; MSI-L, low microsatellite instability; MS-S, stable microsatellites; CRC, colorectal cancer.