There was a noticeable amplification level difference between affected and unaffected family members and normal controls, suggesting that the proband (IV‐11) and all the affected family members (III‐5, III‐9, IV‐2, V‐5, V‐11) have a novel heterozygous deletion of exon 3–16 of the APC gene that is associated with FAP in this family. Here, APC is linked to Familial adenomatous polyposis.