Rare diseases in the spotlight

Rare diseases are likely to get more attention now that an international consortium of patient advocacy groups and research funders has vowed to deliver 200 new therapies by 2020. For people with these diseases, such attention must seem long overdue.

Drug companies currently don’t have much incentive to develop drugs for diseases that affect fewer than 200,000 people, but almost 7,000 rare diseases exist affecting a total of about 25 million Americans.

Many are caused by mutations in a gene. The National Institutes of Health is opening a center in the fall to translate research findings in genetics to usable therapies, the Associated Press reports.

The NIH already has grant programs to spur research in rare diseases. The NIH’s Therapeutics for Rare and Neglected Diseases program has a pipeline of projects. Its pilot projects offer a glimpse into some of the diseases that, though rare, can nonetheless have debilitating consequences.

—Schistosomiasis (also known as bilharzia or snail fever): Infection begins when a parasitic worm carried by freshwater snails penetrates the skin and lays eggs in blood vessels. First come rashes, then fever and chills, followed by liver and other organ damage over time. Researchers recently decoded the genomes of two schistosomiasis-causing parasites, which may allow researchers to find ways to inhibit the parasites’ growth. About 200 million people worldwide have the disease, and 280,000 die from it each year.

—Niemann-Pick Type C: In this condition, fatty deposits accumulate in the spleen, liver, lungs, bone marrow and brain. Type A, the most common, is fatal in infants. Type C can appear early in life or in young adulthood; it causes brain damage and ultimately can affect walking, swallowing, seeing and hearing. Only about 500 children in the world are known to have Type C. Researchers have found two genes that can contribute to Type C and Type D, but progress is slow.

—Hereditary inclusion body myopathy: Usually starting in young adulthood, the disease causes muscle-wasting, leading to severe disability in 10-20 years. A clinical trial in 2006 found mild benefits from intravenous immune globulin, essentially antibodies from blood plasma. A small gene therapy trial is underway, and stem cell therapies are being considered.

—Sickle cell disease: Crescent, or sickle-shaped, blood cells block blood flow in vessels, and can lead to stroke, organ failure or death. The disease affects about 70,000 to 100,000 people in the U.S., mostly African Americans. Only one effective medication exists to help prevent deaths. But a few children and adults have been cured by blood and bone marrow transplants.

—Chronic lymphocytic leukemia : This is the most common type of leukemia, a cancer of the bone or blood, found in adults. About 15,000 people are diagnosed each year (and about 101,000 people live with it).

The new consortium’s goal is to have 200 new therapies in nine years. Many people, in seemingly isolated disease groups, are waiting.