Genetic predisposition to clinical manifestations in familial adenomatous polyposis with special reference to duodenal lesions.
OBJECTIVE
In familial adenomatous polyposis (FAP), genetic predisposition for duodenal adenomatosis has not been investigated precisely. The aim of this study was to investigate the correlation between adenomatous polyposis coli (APC) gene mutation and duodenal adenomatosis in FAP.


METHODS
APC gene mutation was determined by means of a protein truncation test in 34 patients from 25 families with FAP. The prevalence and grade of duodenal adenomatosis were compared among the proximal mutation group (exons 1-9), the distal mutation group (exons 10-15), and the undetermined groups. The correlation between the course of duodenal adenomatosis and APC gene mutation was retrospectively investigated in 19 patients.


RESULTS
The prevalence of duodenal adenomatosis was lower in the proximal mutation group (44%) than in the distal mutation (100%) and undetermined (83%) groups. In patients with positive duodenal adenomatosis, the endoscopic grade did not differ among the groups. The endoscopic grade increased in two of the four patients with the proximal mutation group (50%), in three of 10 patients with the distal mutation group (30%), and in two of five patients (40%) with the undetermined group.


CONCLUSIONS
Truncating APC gene mutation proximal to exon 9 may contribute to the less frequent development of duodenal adenomatosis in FAP, but severity and progression of duodenal adenomatosis do not seem to be determined by APC gene mutation alone.
Matsumoto
Takayuki
T
Department of Endoscopic Diagnostics and Therapeutics, Kyushu University Hospital, Fukuoka, Japan.
Lida
Mitsuo
M
Kobori
Yoichiro
Y
Mizuno
Mitsuru
M
Nakamura
Shotaro
S
Hizawa
Kazuoki
K
Yao
Takashi
T
D011125:Adenomatous Polyposis Coli / Q000175:diagnosis / Q000453:epidemiology / Q000235:genetics*; D000293:Adolescent; D000328:Adult; D017677:Age Distribution; D000368:Aged; D002648:Child; D003113:Colonoscopy; D004378:Duodenal Diseases / Q000175:diagnosis / Q000453:epidemiology / Q000235:genetics*; D004384:Duodenoscopy; D005260:Female; D017491:Genes, APC; D020022:Genetic Predisposition to Disease / Q000453:epidemiology; D005820:Genetic Testing; D006801:Humans; D007564:Japan / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D015995:Prevalence; D011336:Probability; D012189:Retrospective Studies; D012307:Risk Factors; D017678:Sex Distribution; D018709:Statistics, Nonparametric