Immigration spurs rise of sickle cell anemia in U.S.

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Immigration to the United States is resulting in population shifts that are contributing to a rise in sickle cell anemia, researchers say.

Many Americans wrongly believe sickle cell is a disease that affects only blacks. But in fact, one in every 16 Hispanics -- the fastest-growing U.S. immigrant group -- also carries the genetic trait that causes the potentially deadly disease, according to health officials.

Most carriers of the sickle cell genetic trait do not suffer from the incurable and severely painful blood disease, which only occurs in offspring of parents who both carry the trait.

The number of Hispanic sickle cell cases in the United States has been rising rapidly, and one in every 900 Hispanic infants in this country is born with the disease, said Gil Pena, outreach director for the American Sickle Cell Anemia Association (ASCAA).

Yet the ASCAA's Web site cites far lower rates -- as low as 1 in 1,400 births -- of sickle cell disease among Hispanics. "That's old information," said Mr. Pena, adding, "Hispanics are most at risk because we are multiracial."

It is currently estimated that between 72,000 and 80,000 people in this country have some form of sickle cell disease, according to the National Heart, Lung and Blood Institute. About 1,000 new cases are reported yearly. Deaths from sickle cell average about 3,500 annually.

Those figures are only estimates, however, and while Mr. Pena believes the actual incidence of sickle cell is higher, other authorities suggest that an increase in diagnosis of the disease is in fact the result of mandatory testing of newborns for the trait, now required in 48 states.

The biggest risk group for the disease is those with ancestors from sub-Saharan Africa. About one in 12 blacks carries the sickle cell gene, and about one in 400 blacks actually develops sickle cell disease, said Ira Bragg-Grant, executive director of the American Sickle Cell Anemia Association based at the Cleveland Clinic.

The latest federal data from the National Newborn Screening and Genetics Resource Center, however, indicate the rate of sickle cell disease in newborn blacks is higher: one in 350 in the year 2000.

Despite some indications that sickle cell disease is increasing in the United States, Mrs. Bragg-Grant said there is no resurgence.

"What we're seeing today is not a return of sickle cell anemia, because the disease was never eradicated," Mrs. Bragg-Grant said. "Instead, what we're seeing is a stronger awareness of sickle cell."

That awareness, Mrs. Bragg-Grant said, is a result of "new developments in science" and requirements by most states to screen newborns for sickle cell, she said. Mrs. Bragg-Grant said only two states -- New Hampshire and South Dakota ?? do not require such testing.

It is a common misconception that sickle cell only affects blacks. Mrs. Bragg-Grant said the disease also occurs in Caucasians, especially those with Mediterranean backgrounds such as Italians and Greeks, as well as among Turks and persons of Middle Eastern ancestry.

"We get requests for information from countries such as Saudi Arabia and India, which both have large sickle cell disease populations," she noted. The disease also is present in Israel, Lebanon and Yemen, according to the ASCAA.

Official data indicate sickle cell disease occurs in Caucasians at a rate of one in 58,000 births, Mr. Pena said. "But I don't believe those figures," he said, suggesting the actual rate is higher.

"More and more Caucasians, especially those of Mediterranean background, are carrying" the gene for thalassemia, an inherited disorder of red blood cells that, like sickle cell disease, is an anemia caused by defects in the production of hemoglobin, Mr. Pena said.

Reported rates of sickle cell disease may be too low because the disorder takes many forms. "There are 1,625 variations of sickle cell hemoglobin," Mr. Pena said.

In sickle cell anemia, patients have an abnormal kind of hemoglobin in their red blood cells. Their blood cells live only a fraction of the time that normal blood cells survive, and they become stiff, misshapen and have trouble passing through small blood vessels.

"This causes anemia and excruciating pain," said Mrs. Bragg-Grant. In some cases, the blood cells are shaped like sickles, which was the origin of the disease's name. Costs of treating the disease "are astronomically high," she said.