Fanconi anemia usually reveals itself before children are 12 years old, but in rare cases no symptoms are present until adulthood. Fanconi anemia patients are usually smaller than average. They may feel extreme fatigue and have frequent infections. Nosebleeds or easy bruising may be a first sign of the disease. Blood tests may reveal a low white cell, red cell or platelet count or other abnormalities. Sometimes myelodysplasia, AML, or squamous cell carcinoma in a young adult is the first sign of FA.
FA sometimes is evident at birth through a variety of physical defects. These may include any of the following:
- Hand and arm anomalies: misshapen, missing or extra thumbs or an incompletely developed or missing radius (one of the arm bones).
- Skeletal anomalies of the hips, spine, or ribs.
- Kidney problems, including missing or horseshoe kidney.
- Skin discoloration (café-au-lait spots); portions of the body may have a suntanned look.
- Small head or eyes.
- Mental retardation or learning disabilities.
- Low birth weight.
- Gastrointestinal difficulties.
- Small reproductive organs in males.
- Defects in tissues separating chambers of the heart.
Testing for FA
For US-based and international testing resources, see the Fund's International Treatment and Testing Resource Guide
The definitive test for FA at the present time is a chromosome breakage test: some of the patient's blood cells are treated, in a test tube, with a chemical that crosslinks DNA. Normal cells are able to correct most of the damage and are not severely affected, whereas FA cells show marked chromosome breakage. The two chemicals commonly used for this test are DEB (diepoxybutane) and MMC (mitomycin C). These tests can be performed prenatally on cells from chorionic villi or from the amniotic fluid.
Many cases of FA are not diagnosed at all or not diagnosed in a timely manner. FA should be suspected and tested for in any infant born with the thumb and arm abnormalities described previously. Anyone developing aplastic anemia at any age should be tested for FA, even if no other defects are present. Many FA patients show no other abnormalities. It is absolutely essential to test for FA before contemplating bone marrow transplantation for aplastic anemia. The regimen used to prepare patients for transplant is very different for FA patients as FA patients tolerate radiation and chemotherapy very poorly.
While the total number of FA patients is not documented worldwide, scientists estimate that the carrier frequency (carriers are people carrying a defect in an FA gene, whose matching FA gene is normal) for FA in the U.S. is 1 in 181. The incidence rate, or the likelihood of a child being born with FA, is about 1 in 131,000 in the U.S., with approximately 31 babies born with FA each year in this country.**
**Rosenberg, P. S., Tamary, H. and Alter, B. P. (2011), How high are carrier frequencies of rare recessive syndromes? Contemporary estimates for Fanconi Anemia in the United States and Israel. American Journal of Medical Genetics Part A, 155: 1877–1883. doi: 10.1002/ajmg.a.34087
Revised Sept. 2011