Anticipation phenomenon in familial adenomatous polyposis: an analysis of its origin

Table 1 Deceased subjects in each generation, n (%)

Generation	Total	Deceased	Age at death (-x±s, years)	Early childhood death* (% of the deceased cases)
Parent	2958	1952 (66.0)b	41.6 ± 26.2	359 (18.4)
Proband	4273	1687 (39.5)b	26.3 ± 22.3	563 (33.4)
Child	2395	252 (10.5)b	15.8 ± 16.8	119 (47.2)

^bP < 0.001, among the generations;

^*Death before the age of five years.

Table 2 The proportion of causes of death in each generation and their mean age at death (each number of deaths is shown as a proportion to the number of FAP deaths)

Generation	FAP	Extra colonic malignancies	Other diseases	Unknown cause	Death in childhood
Parent	1.00*	0.37	1.24	0.84b	0.78
n = 1952	(50.9 ± 12.4)	(57.6 ± 14.4)	(58.2 ± 19.6)	(36.7 ± 19.8)a
Proband	1.00	0.11	0.37	0.19	0.84
n = 1687	(42.3 ± 12.3)	(46.2 ± 15.8)	(36.7 ± 19.0)	(22.7 ± 16.7)
Child	1.00	0.13	0.44	0.14	1.53
n = 252	(33.3 ± 8.8)	(26.2 ± 16.3)	(22.9 ± 14.2)	(21.9 ± 14.2)

FAP: Death from familial adenomatous polyposis and colorectal cancer. n: Total number of deaths.

^*: Deaths from FAP were calculated as 1.00. (^-x±s, years): Age at death.

^aP < 0.05, vs other causes of death;

^bP < 0.001, vs other two generations.

Table 3 Age at death in the FAP patients, n (%)

Generation	Total number of subjects	Patients with FAP*	Deceased FAP patients	Age at death (-x±s, years)
Parent	2958	508 (17.2)	460 (90.6)	50.9 ± 12.4b
Proband	4273	1316 (30.8)	675 (51.3)	42.3 ± 12.3b
Child	2395	337 (14.1)	78 (23.1)	33.3 ± 8.8b

^bP < 0.001, among the generations FAP: Familial adenomatous polyposis.

^*FAP patients and patients with colorectal cancer.

Table 4 Deceased parent-child pairs of FAP patients classified by the parental status of the child, and the anticipation

Age at death	Group A	Group Bb
Parent > child	184	93
Parent ≤ child	57	5

Group A: Parent-child pairs in which the child had become a parent. Group B: Parent-child pairs in which the child had not had any child.

^bP < 0.01, vs Group A.