“Merriam-Webster’s” dictionary defines “rare” as “seldom occurring or found: UNCOMMON.” Rare diseases are certainly “uncommon.” To qualify as “rare” in the United States, a disease must occur in fewer than 200,000 people. Because relatively so few people are affected, these diseases don’t always appeal to researchers, so making great strides toward curing or eliminating them altogether is not occurring. Some rare diseases don’t even seem that rare since you hear about them in the media, or they have products that are made for the management of the disease.
Eighty percent of rare diseases, also known as orphan diseases, have an identified genetic origin and 50 percent of these diseases affect children. Around 6,000 rare diseases affecting approximately 300 million people worldwide have been discovered. In the United States, about 30 million people are living with a rare disease, which is about 1 in 10. Odds are pretty good that you know someone with a rare disease.
Many rare diseases affect the digestive system. One of these just happens to be an intolerance to sugar. The formal name for this condition is “Congenital Sucrase-Isomaltase Deficiency” (CSID), also known as Sucrose Intolerance. People who have CSID experience negative digestive symptoms like gas, abdominal pain, diarrhea, and nausea when they consume food with sucrose.
Sucrose is also known as “table sugar” or “white sugar,” which most of us keep in a canister for baking or stirring into our coffee. Sucrose is a disaccharide, which means it contains two sugars. It must be split apart by the sucrase enzyme to release the two sugars, which are then absorbed into the intestinal wall. CSID is genetic and several different genetic mutations have been identified, which makes diagnosing it by genetic testing alone very difficult. A tissue biopsy from the small intestine is one way to help diagnosis CSID, and breath testing is also an option.
CSID is one of the many rare diseases that is recognized on the last day of February each year for International Rare Disease Day. The last day of February was selected since every four years we have a 29th day, which seems “rare.”