OOA (Old Order Amish)

Inheritance: autosomal recessive
Genes: RAG1

Familial reticuloendotheliosis with eosinophilia
SCID with hypereosinophilia
T cell positive
B cell negative
NK cell positive

Hemolytic anemia

Omenn Syndrome

Clinical Characteristics

General description (for patients):   

This disorder is only one of several immune system deficiencies found among plain people whose hallmark is extreme susceptibility to infection. Omenn syndrome has other findings such as red, thickened skin, sparse hair, enlarged liver, spleen and lymph nodes. Anemia is common. The common denominator to SCID (severe combined immunodeficiency) lies in the inability of the white blood cells to fight infections.

Medical description: 

This form of SCID characteristically presents with not only severe neonatal infections, but also reticuloendotheliosis, eosinophilia, hepatosplenomegaly and lymphadenopathy. Hemolytic anemia is often present. Immunoglobulins G, M, E, and A may be low and even undetectable. Lymphocyte B cells are low in numbers.


Mutations in several genes are responsible for this disease, including RAG1 and Rag2 on chromosome 11 (11p13) and Artemis on chromosome 10 (10p). Omenn syndrome is an autosomal recessive disorder and a novel mutation (c.2974A>G) has been identified among the Amish of Eastern Pennsylvania.


Prompt recognition is important for infections must be treated vigorously. Allogenic bone marrow transplantation with parenteral nutrition has been successful in restoring immunological competency.


Generally fatal in the first years of life unless bone marrow transplantation is used.

Ancillary treatments and support:

Good nutrition, hydration, and correction of anemia are indicated.

Specialists and specialty centers:

Immunologist, pediatrician, infectious disease, nutritionist, hematologist.


Strauss, K.A., Puffenberger, E.G., Bunin, N., Rider, N.L., Morton, M.C., Eastman III, J.T., and Morton, D.H.: Clinical application of DNA microarrays: molecular diagnosis and HLA matching of an Amish child with severe combined immune deficiency. Clin. Immun. 128: 31-38, 2008. PubMed ID: 18442948

Gomez, L., Le Deist, F., Blanche, S., Cavazzana-Calvo, M., Griscelli, C., and Fischer, A.: Treatment of Omenn syndrome by bone marrow transplantation.  J. Pediat. 127: 76-81, 1995. PubMed ID: 7608815


Immune Deficiency Foundation