A major genetic study has defined the nature of the relationship between a rare liver disease called primary sclerosing cholangitis (PSC) and inflammatory bowel disease (IBD). The effort is the largest to study PSC to date.
Prior to the project, experts weren't sure whether PSC was a complication of IBD. The study found that while 70 percent of patients suffering from it also have IBD, PSC is a unique disease, according to ScienceDaily.
PSC researchers hailed from 13 countries in Europe and North America. Their discovery paves the way for developing treatments to target pathways potentially involved in causing the liver disease.
PSC is an autoimmune disorder that causes inflammatory swelling, scarring, and damage to bile ducts, PubMed Health reports. ScienceDaily says the illness affects only about 1 in 10,000 individuals, can lead to liver failure, and is the most common reason for liver transplants.
A specific cause has eluded researchers for years. The Mayo Clinic says that while PSC can develop at any age, it typically occurs between 25 and 45 and is more common in men than in women. Even among patients with IBD, however, it's rare.
The two major types of IBD are Crohn's disease and ulcerative colitis. According to the Crohn's & Colitis Foundation of America, IBD affects around 1.4 million Americans. The cause or causes of both illnesses remain unknown.
The PSC study collected a huge number of DNA samples. Scientists noted nine new genetic PSC-associated regions. They also took a closer look at three regions of the genome already linked to the liver illness. They realized it was a distinct disease when they found that just six of the 12 regions were also associated with IBD.
Use of a genotyping chip allowed scientists to see genetic differences between PSC and IBD, as well as similarities. They predict that as they collect more DNA, they will be able to pinpoint targets likely to respond to therapy.
Additional research showed 33 more genetic regions linked to other autoimmune illnesses. Those conditions included celiac disease, type 1 diabetes, rheumatoid arthritis, psoriasis, and sarcoidosis, in addition to Crohn's disease and ulcerative colitis. Defining genetic relationships between PSC and those conditions could eventually lead to testing drugs known to be effective for those illnesses as therapies for the liver ailment.
I had not heard of PSC until I recently underwent tests to check out my gallbladder. After the radiologist's report noted some unusual liver findings, the possibility of primary sclerosing cholangitis came up.
The illness is a potential culprit due in part to the fact that I have Crohn's disease. While PSC is a sobering illness, the discovery that this rare liver disease is a distinct illness rather than a complication of IBD is somehow heartening as I search for the precise cause of my discomfort.
Vonda J. Sines has published thousands of print and online health and medical articles. She specializes in diseases and other conditions that affect the quality of life.
- Disease & Medical Conditions
- inflammatory bowel disease
- primary sclerosing cholangitis