Final answer:
Mutations in NOD2 or ATG16L1 lead to an increased susceptibility to Crohn's disease, which is influenced both by genetic predisposition and environmental factors.
Step-by-step explanation:
Mutations in NOD2 or ATG16L1 are associated with increased susceptibility to Crohn's disease. Crohn's disease is a complex condition that arises from a combination of genetic and environmental factors, leading to an impaired immune response and chronic inflammation within the gastrointestinal tract. The presence of mutations in genes like NOD2 or ATG16L1 contributes to this genetic predisposition. While genetic factors play a significant role in Crohn's disease, environmental aspects such as smoking and diet are also important in disease development. Crohn's disease is diagnosed via colonoscopy and is often characterized by a familial pattern, with siblings of afflicted individuals having a higher risk of developing the disease.