Table 1

APC germline mutations in 680 index patients grouped according to number of colorectal adenomas and family history

Subgroup according to No polyps and family history	No index patients	No APC germline mutations detected	Detection rate of germline mutations (%)
>100 adenomas	268	156	58.2
Familial	145	97	66.9
De novo^1-150	31	26	83.9
No information	92	33	35.9
<100 adenomas	101	32	31.7
Familial	44	17	38.7
De novo	10	4	40.0
No information	47	11	23.4
No of adenomas unknown	311	139	44.7
Familial	168	99	58.9
De novo	12	10	83.3
No information	131	30	22.9
Total	680	327	48.1

↵1-150 Both parents of patients classified as “de novo” had either negative colonoscopies at age >50 years or were still healthy at an advanced age.