SNP Shot: Genomic Insights

Primary sclerosing cholangitis (PSC) is a disease impacting the bile ducts. These ducts transport bile, a fluid produced in the liver that aids in fat digestion, to the gallbladder for storage, and then to the small intestine for use in digestion. In PSC, inflammation (cholangitis) causes scarring (sclerosis) and narrowing of these bile ducts. This blockage prevents bile from reaching the gallbladder and small intestine, leading to a buildup of bile in the liver.

PSC is typically diagnosed around age 40 and affects men about twice as often as women, for reasons not yet understood. Many individuals are diagnosed with PSC through routine blood tests revealing liver issues, even without experiencing noticeable symptoms. When symptoms are present, early signs include extreme fatigue, abdominal discomfort, and severe itching (pruritus). As the disease progresses, individuals may develop jaundice (yellowing of the skin and eyes) and an enlarged spleen (splenomegaly). Ultimately, the accumulation of bile damages liver cells, leading to chronic liver disease (cirrhosis) and eventual liver failure. The inability to digest fats due to lack of bile results in undigested fats passing through the body, leading to weight loss and deficiencies in fat-soluble vitamins. A deficiency in vitamin D, a fat-soluble vitamin essential for calcium absorption and bone health, can lead to thinning of the bones (osteoporosis) in those with PSC.

PSC is frequently associated with inflammatory bowel disease (IBD), characterized by intestinal inflammation that causes ulcers and abdominal pain. The connection between these two conditions remains unclear. Approximately 70% of people with PSC also have IBD, most commonly ulcerative colitis. Individuals with PSC are also more prone to autoimmune disorders like type 1 diabetes, celiac disease, or thyroid disease. Autoimmune disorders arise when the immune system mistakenly attacks the body's own tissues and organs. Furthermore, people with PSC have a higher risk of developing cancer, particularly bile duct cancer (cholangiocarcinoma).

Inheritance:

The inheritance pattern of PSC is currently unknown, as it likely involves a combination of genetic and environmental factors. However, the condition tends to run in families, and having a family member with PSC increases the risk of developing the disease.