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updated: 11/21/2010 5:32 PM

The difference between sickle cell trait, disease

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I was aware my patient had a history of an abnormal blood test, but I found the toddler to be in perfect health. After examining the 2-year-old during his well-child visit, his parents and I revisited the medical issue that had turned up on his newborn screen, done 24 months earlier. That particular blood test, while otherwise unremarkable, revealed the little guy had sickle cell trait.

Sickle cell trait is a carrier state, does not result in anemia and generally does not lead to the serious complications often seen in sickle cell disease. Sickle cell disease one of the more widely known blood disorders is a condition in which the affected patient manufactures abnormal hemoglobin. Red blood cells take on a sickle or crescent shape, instead of the normal circular disc-like shape, interfering with smooth, efficient circulation. During sickle cell crises, patients can experience pain and infection, as well as organ damage.

Sickle cell disease and trait are both inherited conditions. The disease occurs when a child inherits one copy of the sickle cell gene from each parent, while trait results when only one parent passes along a copy of the abnormal gene to their child.

According to the National Institutes of Health, sickle cell anemia is most common among families originating from Africa, South America, Central America (especially Panama), the Caribbean islands, Mediterranean countries, India and Saudi Arabia. The sickle cell gene was thought to have evolved within these geographic areas due to its somewhat protective effect against malaria.

Approximately 100,000 Americans have full-blown sickle cell disease, while sickle cell trait is found in 2 million Americans. Disease occurs in one out of every 500 African-Americans, with one out of 12 African-Americans carrying the gene as sickle cell trait.

When caring for infants and toddlers, it's important to stress that SCT is not a disease state. At the same time, it's also important for parents to know that genetic counseling will be of use as the child reaches adulthood since with each pregnancy, two carrier parents have a 25 percent chance of producing offspring with sickle cell disease.

Sickle cell trait is generally asymptomatic with a few uncommon exceptions. The Sickle Cell Information Center reports that painless hematuria (blood in the urine) is seen in 1 percent to 4 percent of patients with the trait. Pregnant women with SCT are thought to be at increased risk of urinary tract infections.

Pain episodes can occur in some individuals with sickle trait who venture to altitudes above 12,000 feet. In rare instances, extreme exertion in SCT has resulted in episodes of splenic infarction interruption of blood flow to the spleen with tissue damage.

With the start of the 2010-11 academic year, the NCAA required that all incoming Division I athletes be tested, or show evidence of past testing, for sickle cell trait. Athletes still have the option to decline SCT testing after signing a waiver releasing their university from any potential liability associated with the condition.

The NCAA does not restrict student athletes with sickle cell trait from participating in the sport of their choice since medical complications are rarely seen during competition.

The association does recommend that athletes with sickle cell trait, along with their unaffected teammates, follow some common-sense training rules. The risk of medical complications from SCT is greatly decreased if athletes stay well-hydrated, gradually acclimate to high degrees of heat, humidity or altitude, spend several weeks stepping up conditioning before reaching peak levels of exertion and skip vigorous exercise during episodes of acute illness or fever.

• Dr. Helen Minciotti is a mother of five and a pediatrician with a practice in Schaumburg. She formerly chaired the Department of Pediatrics at Northwest Community Hospital in Arlington Heights.