The Etiology of Ibd Through Genetics

At the age of 10, my sister was diagnosed with a severe case of ulcerative colitis (UC), a disease that affected her entire colon. She has experienced intense symptoms of abdominal pain and bloody diarrhea, with short periods of remission. Since no medication was working properly to help decrease her flares, she underwent surgery to remove her colon. She is now 23 years old with a 10-month old son. It was scary when my sister was diagnosed with ulcerative colitis because doctors were (and still are) not sure of the cause of this disease, but they do know this disease tends to run in families. My family and I were scared to think we might be diagnosed with ulcerative colitis. When my sister got pregnant, there was concern whether her baby would be diagnosed with ulcerative colitis.

The Human Genome Project, completed in April 2003, identified the sequence of the human genome to view a person's genetic heritage. Coordinated by the U.S. Department of Energy and the National Institutes of Health, the project goals were to define the 20,000-25,000 genes in the human DNA, and determine the sequences of the 3 billion chemical base pairs. Genome-wide association studies have identified more than 50 loci for IBD.

Every cell in the human body has a genetic code passed down from parent to child. Genes not only have the ability to identify a person by their physical characteristics, but they build awareness if a person were to develop certain diseases or disorders. A genetic disease starts in the genome region of a person's body. The genome has to be working improperly for a genetic disease to occur. For instance, a change in the single base in the DNA of a single gene may cause this abnormality. There are 46 human chromosomes, 22 of which are autosomal chromosomes and 2 which are sex chromosomes. They house 3 billion base pairs of DNA that hold approximately 20,500 protein-coding genes (less than 5% of the genome). A large mutation may be caused by too much or too little of a chromosome or set(s) of chromosomes.

The susceptibility of IBD includes genetic factors that increase the chances of individuals being diagnosed with the ailment. Immediate family members of patients with IBD are about 3 to 20 times more likely to be diagnosed with the ailment than the general population. Having a sibling with CD increases the chances of developing the disease by 30 times compared with the general population. Children with parents who have IBD have a 33 percent chance of developing the disease by age 28. Clinical evidence behind the heritable risk of IBD has been done on twins and revealed that genetic factors may be more important in Crohn's disease (CD) patients than in ulcerative colitis (UC) patients. A study done on 80 twins revealed that CD twins had a higher inheritance rate than UC twins (58 versus 6 percent).

The likeliness in symptoms has been observed from the location and type of CD patients. With 554 patients, Crohn's Disease ran in the family of 17 percent of patients. The site of disease was observed in 2 family members from 86 cases and 82 percent were concordant for the clinical type of disease. Another report issued that concordance for disease location and type were present in 56 and 49 percent in families out