Inherited GI Disorders, Nutrition & Abdominal Hernias

By completing this question set, you will be able to classify hereditary colorectal cancer syndromes by gene, mutation type, inheritance pattern, polyp type, cancer risk, and extracolonic manifestations — distinguishing the adenomatous polyposis syndromes (FAP, Lynch, MUTYH) from the hamartomatous syndromes (Peutz-Jeghers, juvenile polyposis). You will explain why FAP carries 100% lifetime colorectal cancer risk requiring prophylactic colectomy, while Lynch syndrome produces cancer without polyposis via a completely different molecular mechanism. You will recognize MUTYH-associated polyposis as the only major hereditary CRC syndrome with autosomal recessive inheritance and apply the clinical implications for sibling counseling. You will explain the genetic mechanisms of the four major inherited metabolic GI diseases — hemochromatosis (HFE/hepcidin), Wilson's disease (ATP7B/copper transport), alpha-1 antitrypsin deficiency (SERPINA1/ER accumulation vs deficiency), and hereditary pancreatitis (PRSS1/SPINK1/CFTR) — and predict the phenotype from the mechanism. You will identify fat-soluble and water-soluble vitamin deficiencies from their GI disease contexts and recognize the unique clinical manifestations of each — including the thiamine-before-glucose principle in Wernicke's encephalopathy and the spinocerebellar syndrome of vitamin E deficiency. You will classify abdominal hernias by anatomic location, identify the diagnostic keys that distinguish indirect from direct inguinal hernias (relation to inferior epigastric vessels, Hesselbach's triangle), recognize femoral hernias as the highest-risk variant for strangulation, and diagnose obturator hernia from the Howship-Romberg sign.