[Hereditary colorectal cancer: Molecular analysis of APC and MLH1 genes].
BACKGROUND
Among colorectal cancer hereditary variants, two syndromes show a predisposition to the disease based on germline mutations: Familial Adenomatous Polyposis (FAP) and Hereditary Nonpolyposis Colorectal Cancer (HNPCC).


OBJECTIVE
To screen mutations in FAP and HNPCC families in Chile.


METHODS
Two FAP and one HNPCC families were studied. The APC gene (for FAP patients) and the MLH1 gene (for HNPCC patients), were screened for mutations on genomic DNA. The molecular analysis was performed through polymerase chain reaction, Single Strand Conformer Polymorphism (SSCP) and DNA sequencing. Mutations were defined as changes in the DNA sequence leading into a stop codon and a truncated protein.


RESULTS
In the two FAP families the analysis revealed a mutation consisting in the deletion of five nucleotides named c.3927_3931delAAAGA. The genetic study of the HNPCC family demonstrated the insertion of one adenine in codon 168 of exon 6, named c.504insA.


CONCLUSIONS
Germ-line mutations were identified in the three families. The relevance of these studies in a better knowledge of cancer susceptibility, and the possibility of identifying in relatives in risk by molecular diagnosis.
Bellolio R
Felipe
F
Departamento de Cirugía Digestiva, Hospital Clínico, Facultad de Medicina, Pontificia Universidad Católica de Chile, Santiago, Chile.
Alvarez V
Karin
K
De la Fuente L
Marjorie
M
León G
Francisca
F
Fullerton M
Demian A
DA
Soto D
Gonzalo
G
Carvallo de S Q
Pilar
P
López-Köstner
Francisco
F
D011125:Adenomatous Polyposis Coli / Q000235:genetics*; D000293:Adolescent; D000328:Adult; D015179:Colorectal Neoplasms / Q000175:diagnosis / Q000235:genetics*; D003123:Colorectal Neoplasms, Hereditary Nonpolyposis / Q000235:genetics; D005260:Female; D005787:Gene Frequency; D017491:Genes, APC / Q000502:physiology*; D018095:Germ-Line Mutation / Q000235:genetics; D006801:Humans; D008297:Male; D008875:Middle Aged; D009154:Mutation / Q000235:genetics*; D010375:Pedigree; D017422:Sequence Analysis, DNA