Table 1. Baseline features of FAP patients who underwent endoscopic ampullectomy (N=26).

General Characteristics
Sex (M: F), n (%)	9 (34.6): 17(65.4)
Mean age at diagnosis of FAP, years (range)	27.8 ± 9.9 (16-47)
FAP diagnoses, n (%)	26
FAP family	18 (69.2)
FAP de novo	5 (19.2)
AFAP* family	1 (3.9)
AFAP de novo	2 (7.7)
APC gene testing, n (%)
Positive	15 (57.7)
Not done	11 (42.3)
Colectomy, n (%)	23 (88.5)
Mean age at colectomy, years (range)	30.7 ± 8.1 (17-47)
Spigelman's stage at diagnosis, n (%)
Stage I	1 (3.8)
Stage II	21 (80.9)
Stage III	3 (11.5)
Stage IV	1 (3.8)
Diagnosis of ampullary adenoma, n (%)
Made at initial screening endoscopy	15 (57.7)
Made at surveillance endoscopy	11 (42.3)

^*AFAP: attenuated FAP