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Friday, Jan 09, 2009 | 01:48 PM
Madisons Foundation - Moms And Dads In Search Of Needed Support
Omenn's Syndrome
Familial Reticuloendotheliosis
Wednesday, 16 July 2003
Last Updated Monday, 18 July 2005
Additional entries in our database that you might find useful:
Severe Combined Immunodeficiency (SCID)
What
Omenn's Syndrome is a rare, inherited disorder of the immune system that belongs to a family of similar immune deficiencies known as SCID, or Severe Combined immunodeficiency. SCID specifically affects three types of cells in our immune system: B lymphocytes, T lymphocytes and natural killer cells. Each of these cells plays an important role in fighting infection. Omenn Syndrome is the type of SCID that only affects B and T lymphocytes. Natural killer cells are normal in number and function.Who
The specific incidence of Omenn’s Syndrome is not known but it is estimated that 1 in 50,000 to 75,000 births is affected by some form of SCID. Equal numbers of boys and girls have been diagnosed with Omenn’s Syndrome and it appears to be more common in people of North American or European descent.Signs and Symptoms
Children usually present within the first three months of life with recurrent ear infections, failure to thrive, swollen lymph nodes, enlarged liver and spleen, chronic diarrhea, and possibly a skin rash where patches of the skin are red and weeping. Infants with this disease are frequently sick and become ill with bacteria and viruses that unaffected babies easily fight off before showing symptoms of an infection.Possible Causes
Omenn's Syndrome is inherited in an autsomal recessive pattern. This means that in order for a child to develop this condition, he or she must inherit a copy of the same inactivated gene from each parent. The parents are usually unaffected because they only have one copy of the inactivated gene and are considered “carriers” for the condition. When two carriers have children, there is a 25% or 1 in 4 chance for a child to be affected. The specific genes that are involved in Omenn’s Syndrome are located on chromosome 6 and are responsible for regulatory proteins that function to create a normal mixture of B and T lymphocytes during infancy. The B and T cells are created in the bone marrow and thymus gland, respectively, and each type is programmed to recognize different foreign elements such as bacteria, viruses, or parasites. When the regulatory proteins, called recombination-activating genes, or RAGs are defective as in Omenn’s syndrome, the immune system loses its ability to produce diverse B and T cells. As a result, the body is susceptible to infection of all types.Diagnosis
Making the diagnosis of Omenn’s syndrome requires early recognition of the characteristic signs and symptoms of immune deficiency. Frequent infections (more than 2 or 3 per month), poor growth, and a persistent, generalized rash are warning signs. Blood tests may be drawn to evaluate for anemia (low red blood cell counts), low platelets, low levels of B and T lymphocytes, and elevated eosinophil counts or increased levels of immunoglobulin type E (specific components of the immune system); all of these results are typical of Omenn’s syndrome. The eosinphil and IgE levels are elevated as a result of the body’s attempt to compensate for its lack of diverse B and T cell populations. A basic chest x-ray may show that the child is lacking a thymus, which will reinforce the presence of a weakened immune system. DNA analysis looking for RAG mutations can help confirm the diagnosis. prenatal diagnosis is also available either by chorionic villi sampling or amniocentesis procedures.Treatment
While there is no known cure for Omenn’s syndrome, bone marrow transplantation has been performed to replace the ineffective immune system. Until this procedure is performed, and even for months to years afterwards, children are usually placed on a regimen of daily antibiotics to hopefully prevent life-threatening infections. Any change in health, including minimal rise in temperature or diarrhea, is closely evaluated through cultures and biopsies to identify the foreign organism so that it can be targeted specifically before it causes a severe infection. Another treatment that has been and continues to be researched extensively is gene therapy. The goal of gene therapy is to introduce DNA that contains the genetic material (RAGs) that is missing or defective in Omenn’s disease. This has been met with limited success and is an area of ongoing research. It is also important for patients and families to know that live vaccines (measles, mumps, rubella, chickenpox, oral polio) are not to be given because there is a high likelihood of contracting those diseases. Children with chronic diarrhea that cannot be controlled by antibiotics are often placed on intravenous nutrition to avoid introducing food-borne germs into the digestive system. Finally, parents of affected children should receive genetic counseling for family planning purposes.Prognosis
With a successful bone marrow transplantation and eventual return of normal immune system function, patients can expect to lead healthy, normal lives. A significant percentage of patients have problems with infection or a condition known as “graft versus host disease (GVHD)” during transplant. Children who develop acute or chronic GVHD usually have diminished life spans.Connect with other parents
In the spirit of community and support, Madisons Foundation offers the unique service of connecting parents of children with rare diseases. If you would like to be connected to other parents of children with this disease, please fill out this brief form.Weblinks
Immunedeficiency Foundation
Latest updates and parent support group.
Disease Information Database
Good portal to other useful weblinks.
BMT infonet
Good website to learn about what a bone marrow transplant entails.
Contact a Family
A website from the U.K. that explains the autosomal recessive method of inheritance, explains methods of prenatal diagnosis and allows families to make contact with others that are battling the same diagnosis.
The SCID Homepage
Wonderful resource with information about the disease, treatments and possible complications such as graft vs. host disease, and current research projects.
NMDP
National Marrow Donor Program website.