Fanconi Anemia

Fanconi anemia, a very rare type of anemia, is an inherited genetic disease that leads to severe deficiency of all types of blood cells (aplastic anemia).

Originally, Fanconi Anemia, was described by Swiss pediatrician Fanconi in 1927. Fanconi Anemia is not related to the renal tubular defect that also bears his name.

Fanconi Anemia

According to Fanconi, the characteristic clinical features are:-

• skeletal anomalies particularly involving the radius and thumb
• pigment of skin at skin folds
• squint
• stunted growth
• renal defects
• non-hematologic malignancies like tumors of neck, skin, gastro-intestinal tract, genital tract and head that occur in about 29% of patients

All these patients eventually develop bone marrow failure but this is always delayed. However, many patients develop acute myelogenos leukemia at a very early stage.

Onset of Fanconi Anemia

Fanconi Anemia easily becomes obvious between the ages of 5 and 10. Before the age of 3, onset is very occasional and may not be seen until the second and third decade of the patient's life.

Diagnosis of Fanconi Anemia

in Fetus  – Fetal hemoglobin is raised to higher levels (1-2 grams/dl.)

At Birth  – The correct diagnosis may be suspected at birth if the above congenital defects are present but it is always uncertain when the bone marrow failure will follow. When bone marrow failure develops, a diagnosis of Fanconi Anemia will be suggested by the presence of congenital defects.

Tests to Confirm Fanconi Anemia

The confirmatory test for the presence of Fanconi Anemia is a Chromosome Breakage test. Currently, there are two tests for this purpose:

DEB (Diepoxybutane test)
MMC (Mitomycin C test)

In both these tests, a small number of a patient's lymphocytes (white blood cells) are exposed to one of these two chemical agents which cause the chromosomes in Fanconi Anemia cells to break and re-arrange themselves. The chromosomes of normal cells are more resistant to these chemicals and do not break easily. The amount of breakage in the chromosomes is measured and if the measured values indicate a larger amount of breakages, it is reasonable to assume that the patient is suffering from Fanconi Anemia.

Treatment of Fanconi Anemia

After the diagnosis has been established, treatment of Fanconi Anemia is done by:

Oral Administration of Androgens  Androgens (or artificial male hormones and prednisone. Administration of androgens has been shown to improve blood cell counts in one-half of the patients with Fanconi Anemia. The response is usually drug-dependent and prompt relapse occurs when the therapy is stopped. The patient's response to the therapy is monitored closely and the minimum dosage of androgen required to maintain the patient's blood counts is used.

• Hemotopoietic Growth Factors: Hemotopoietic growth factors are administered to patients and the results have been encouraging.

• Bone Marrow Transplantation: Bone marrow transplantation is done in patients who are severely affected. Bone marrow transplant, if successful, helps in curing the aplastic anemia, which is most life-threatening, in Fanconi Anemia patients.
  • Stem-Cell Transplantation: Hemotopoietic Stem Cell Transplantation is often the only therapy for the hematologic manifestations of Fanconi Anemia.