Dyserythropoietic anaemia

1. Congenital dyserythropoietic anemia

Congenital dyserythropoietic anemia (CDA) is a rare blood disorder, similar to the
thalassemia’s. CDA is one of many types of anemia, characterized by ineffective
erythropoiesis, and resulting from a decrease in the number of red blood cells (RBCs) in
the body and a less than normal quantity of hemoglobin in the blood. This shortage
prevents the blood from carrying an adequate supply of oxygen to the body's tissues,
resulting in various symptoms of anemia including: tiredness (fatigue), weakness, pale
skin, and other similar complications.


Genetics
CDA is transmitted by both parents autosomal recessively (although CDA type III
appears to have an autosomal dominant pattern of inheritance
[2]
) and has over four
different subtypes, but CDA Type I, CDA Type II, CDA Type III, and CDA Type IV are
the most common. CDA type II (CDA II) is the most frequent type of congenital
dyserythropoieticanemia’ss. More than 200 cases have been described, but with the
exception of a report by the International CDA II Registry, these reports include only
small numbers of cases and no data on the lifetime evolution of the disease.
[3]

Types include:
Type OMIM Gene Locus
CDAN1 224120 CDAN1 15q15
CDAN2 224100 SEC23B 20p11.2
CDAN3 105600 CDAN3 15q21
CDAN4 613673 KLF1 19p13.13-p13.12

Treatment

2. Patients with CDA typically get frequent blood transfusions, but this can vary depending
on the type that is acquired. Patients report going every 3–5 weeks for blood
transfusions, and receive somewhere between 1-2 adult units of blood (3-4 child units
for children). In addition, they must undertake chelation therapy to survive;
either deferoxamine (i.e. . . Desferal), deferasirox (i.e. Exjade), or deferiprone (i.e.
Kelfer, Ferriprox, L1) to eliminate the excess iron that accumulates. In a clinical sense,
the disorder is very similar to thalassemia major (Beta-thalassemia) and treated in the
same fashion. Removal of the spleen and gallbladder are common, and problems with
the liver and heart become increasingly important as the individual ages, due to
stresses from low hemoglobin counts and high iron content. Hemoglobin levels usually
run anywhere between 6.0 gm/dl and 7.0 gm/dl in untransfused patients, and between
8.0 gm/dl and 10.0 gm/dl in well transfused patients. It is important to go regularly for
transfusions and to chelate daily in order to maximize good health.
Exjade, an oral chelator approved by the FDA in November 2005, has made chelation
therapy much easier for patients, who previously could only chelate subcutaneously.
Deferiprone, another oral chelator, was also recently approved by the FDA on October
14, 2011.While normal ferritin levels run anywhere between 24 and 336 ng/ml,
hematologists generally do not begin chelation therapy until ferritin levels reach at least
1000 ng/ml. It is more important to check iron levels in the organs through annual MRI
scans (T2* for the heart, R2 for the liver), however, than to simply get regular blood
tests to check ferritin levels (which only show you a trend, and do not reflect actual
organ iron content).

Curative Options
Bone marrow transplant and gene therapy are the only known cures for the disorder,
but each has their own risks at this point in time. Gene therapy is especially promising;
however, as it allows for the autologous transplantation of the patient's own healthy
stem cells rather than requiring an outside donor, thereby bypassing any potential
for graft vs. host disease (GVHD). Clinical trials on one 18 year old boy in France in
2007 have suggested that he is cured of Beta-thalassemia three years later with no
complications noted so far. A second trial on another patient in France is due to occur
sometime by the year 2016.