None — Down Syndrome
Down syndrome is an inherited condition caused by a defect in the 21st chromosome. Humans have 46 chromosomes arranged in pairs (a total of 23 pairs). We inherit two copies of each chromosome – one from our mother and one from our father. Through an error in cell division, an embryo with Down Syndrome inherits three copies of the 21st chromosome. The extra chromosome is replicated every time the affected cells divide. In the most common form of Down Syndrome (called Trisomy 21, accounting for 95 percent of all cases), every cell in the body contains the genetic error.
According to the National Down Syndrome Society, about 400,000 Americans have Down Syndrome. About one in 733 babies are born with the condition annually. A pregnant woman's risk for having a child with Down Syndrome generally increases with age. At 35, the chance is about one in 350. By 45, the chance of having a baby with Down Syndrome is roughly one in 30.
Although the symptoms of Down Syndrome vary, there are common features. Some of the most common traits associated with the condition are: flat face, short neck, small nose and ears, upward slant of the eyes, poor muscle tone, small stature, deep crease in the palm of the hand, and small hands and feet. The National Institute of Child Health and Human Development reports that most people with Down Syndrome have mild to moderate degrees of mental retardation.
Babies with Down Syndrome often have other underlying medical problems. About half of them have some type of congenital heart problem. Nearly two-thirds have a vision problem. Three-fourths have some degree of hearing loss. About 12 percent are born with intestinal malformations.
Living Longer with Down Syndrome: Health Concerns
With better medical care and early intervention for complications, children with Down Syndrome are living well into adulthood. Researchers report in the 1940s, the average lifespan for a child with Down Syndrome was about 12 years. Today, the average life expectancy is about 60.
As adults with Down Syndrome live longer lives, medical concerns become more complicated. Researchers say obesity, thyroid disorders, mitral valve prolapse, hip dysplasia, foot arthritis and osteoporosis are common in adults with Down Syndrome. By 40, nearly all patients have signs of Alzheimer's disease-type dementia. One percent of adults develop leukemia. Studies also show that adults with Down Syndrome tend to develop age-related health problems at a younger age than those in the general population.
Getting the Best Care
Edward Lose, M.D., Clinical Geneticist with the University of Alabama at Birmingham, says that a good portion of care for children with Down Syndrome falls on pediatricians. But as the life expectancy for these patients has increased, many need attention from an adult care provider, like a family practice physician or internal medicine physician. But many adult health care providers don't have the time and expertise to deal with the complex set of health needs of those with Down Syndrome. In addition, patients are often under the care of several different types of health care providers.
The University of Alabama at Birmingham has opened an Adult Down Syndrome Clinic designed specifically for individuals with Down Syndrome and their families. During an appointment, patients and families are assigned a room. Instead of running from one doctor to another, the physicians and health care providers each come to the patient. The system is much more efficient for the patient because all the consultations can be done in a single day. In addition, a single location allows the health care team to meet and discuss the patient's progress and needs, providing better continuity of care. Lose says patients can be seen for routine health care needs as well as specialized care. The Adult Down Syndrome Clinic is modeled after a similar program in Chicago.
For general information on Down Syndrome:
March of Dimes National Association for Down Syndrome National Down Syndrome Society National Institute of Child Health and Human Development