American Medical Association Family Medical Guide - American Medical Association [675]
Most people with Marfan syndrome have abnormal heart valves that may produce a murmur (unusual heart sound) or irregular heartbeat. The aorta (the major blood vessel in the body), which contains an abundance of fibrillin, can weaken. Without treatment, this weakness can cause the aorta to stretch and balloon out to form an aneurysm (see page 599) or tear, causing bleeding into the chest or abdomen and sudden death. Most people with Marfan syndrome are nearsighted, and about half have a dislocation of the lens of the eye. Detachment of the retina (the light-sensitive lining at the back of the eye) also can occur. The syndrome can make a person prone to sudden lung collapse.
Diagnosis
Marfan syndrome is difficult to diagnose because there are no specific laboratory tests for the condition and because the symptoms can vary greatly among people who have the disorder. A doctor usually diagnoses Marfan syndrome by a complete physical examination. If a doctor suspects that a person has Marfan syndrome, he or she may order an echocardiogram (see page 561) and an eye exam to look for the characteristic abnormalities of the disorder.
Treatment
A doctor may prescribe heart medications such as beta blockers (see page 562) to reduce the rate of stretching of the aorta and to decrease the risk of complications. Heart surgery may be necessary if an aneurysm develops or to repair or replace defective heart valves. Some spine deformities can be corrected with a brace or with surgery.
Neurofibromatosis
Neurofibromatosis is a genetic disorder that causes tumors (abnormal masses) to grow along the nerves, including the nerves in the brain. Tumors can also appear under the skin and in the bones. The disorder is the result of a single defective gene that has been inherited from a parent or that became abnormal through a spontaneous mutation (change) in a gene. Most of the tumors produced by the disease, which can grow throughout the body, are not cancerous. However, in rare cases, a tumor in the brain or spinal cord becomes cancerous.
Neurofibromatosis has two forms—type 1 and type 2. Neurofibromatosis type 1 (NF1) is one of the most common genetic disorders, affecting 1 in 4,000 people in the United States. Fifty to 70 percent of cases of NF1 are inherited from a parent; the remaining 30 to 50 percent result from a spontaneous genetic mutation in a parent’s egg or sperm. Neurofibromatosis type 2 (NF2) is much rarer than NF1 and causes tumors to grow around the auditory (hearing) nerves on both sides of the brain and elsewhere in the brain. These tumors can cause brain damage and can be life-threatening.
If you have neurofibromatosis, see a genetic counselor (see page 952) to learn your risk of passing the disorder on to a child.
Symptoms
Most people with NF1 have only mild symptoms and live normal lives, but others have severe symptoms. The most common sign of NF1 is the appearance of flat, light-brown spots on the skin called café au lait (French for “coffee with milk”) spots, which can appear at birth or in early infancy. Children with NF1 usually have six or more of these spots on their body, each spot measuring more than 1/5 inch. By puberty, the spots begin to grow to about ½ inch in diameter. Tumors begin to grow around nerves throughout the body during adolescence and appear as small lumps or bumps under the skin.
A person with NF1 may also have freckles in his or her armpits and groin area, abnormal tissue in the iris (the colored part of