Family should be tested for Marfan syndrome
DEAR DR. GOTT: Recently, all three of my children went to a chiropractor, since all have back problems. The doctor suggested having my middle child seen by a heart specialist because he has flat feet, a curved spine, an indented chest and protruding shoulder bones. It was a good call because the cardiologist found that he has an enlarged aortic valve (following an EKG and an ultrasound). He is now recommending that my son have an MRI of his heart and see a geneticist to determine if he has Marfan syndrome. My son is 14 years old and has asthma, but otherwise, we just thought he was skinny. What are your suggestions about any information the geneticist needs?
DEAR READER: Marfan syndrome is a genetic disorder that affects connective tissues. These tissues are present throughout the body and integral to normal functioning. Because of this, Marfan syndrome can disrupt development and function in several areas of the body, including (but not limited to) the heart, eyes, skeleton and blood vessels.
Symptoms vary greatly among sufferers, even among family members who are affected. Some experience life-threatening complications while others have only mild effects. Some may not even know they are affected. Marfan typically worsens with age.
Signs and symptoms may include a breastbone that protrudes outward or dips inward; a tall, slender build; flat feet; heart murmurs; a curved spine; disproportionately long arms, legs, fingers and toes; extreme nearsightedness; and a high, arched palate with crowded teeth.
Marfan syndrome is caused by a defect (there are actually several defects, all of which can lead to Marfan) in the gene that enables the body to produce a protein that gives connective tissue strength and elasticity. This defect is inherited dominantly, meaning that only one copy of the defective gene is needed in order for the disorder to present. This means that most of those affected also have a parent who is affected. About 25 percent of cases are the result of a spontaneous mutation. Chances of two unaffected individuals having a child with Marfan is about one in 10,000. An individual who is affected on the other hand has a 50 percent chance of having a child with the disorder if the other parent is unaffected.
I did find a case of a newborn who had two affected parents (neither of whom knew they had the syndrome). The baby exhibited symptoms from birth and suffered severe congestive heart failure. He died at 4 months old from complications of pneumonia, and it was thought by the researchers that the baby had inherited defective genes from both parents, thus causing his exacerbated symptoms at birth. The chances of this happening again are slim. Two affected individuals have a 25 percent chance of having a totally unaffected child or a child with two defective genes (likely fatal) and a 50 percent chance of having a child with only one defective gene and the disorder.
Men and women are equally affected. Marfan occurs in all races and ethnic groups.
Complications depend on what areas of the body are affected. This differs depending on the defect. The most serious complications arise when the heart and blood vessels are affected. Valve malformations and aortic aneurysm or dissection are most common. If the eyes are affected, lens dislocation, retinal tears or detachment, cataracts and glaucoma may occur. Chronic obstructive pulmonary disease, sleep apnea, emphysema and collapsed lung can result when the lungs are affected. Shortness of breath during mild or moderate activity may also result if the chest is concave (indented) or if the spine is severely curved, as it restricts the expansion of the lungs on inhalation.
Many cases of Marfan syndrome can be diagnosed without genetic testing, but in some cases, these tests may not provide a clear answer. In this instance, referral to a geneticist for testing may be necessary. If Marfan is present in a family member, other members should consider testing to determine if they also have the disorder. As stated above, some cases may be mild and unnoticed, but it is important to know, especially if you plan on having children, to assess your risk and the risk to the child.
There is no cure or treatment for Marfan syndrome; however, treatment of specific issues that result from the condition can help. It is important to avoid high-risk activities such as weight lifting, football, surfing, ice hockey, scuba diving and rock climbing. Low-risk activities include bowling, snorkeling, skating, golf, modest hiking and doubles tennis.
As for what you need to provide the geneticist, you would be best served by providing your son’s entire medical history, as well as that of your wife, other children and yourself because the odds are that you or your wife is affected and your other children may be, despite outward symptoms.