SNP Shot: Genomic Insights

Omenn syndrome is a genetic immunodeficiency disorder. It falls under the umbrella of severe combined immunodeficiency (SCID), a group of conditions where the body lacks sufficient immune defenses against bacteria, viruses, and fungi. Consequently, individuals with SCID, including those with Omenn syndrome, are highly susceptible to recurrent and persistent infections that can be severe or fatal. Infants with Omenn syndrome commonly suffer from pneumonia and chronic diarrhea. These infections are often caused by opportunistic organisms, which typically don't cause illness in people with healthy immune systems.

Besides immunodeficiency, Omenn syndrome also involves autoimmunity, where the immune system mistakenly attacks the body's own tissues and organs. This leads to symptoms such as intensely red skin (erythroderma), hair loss (alopecia), and an enlarged liver and spleen (hepatosplenomegaly). Furthermore, there is enlargement of lymphoid tissues, including the thymus gland (located behind the breastbone) and lymph nodes throughout the body, which are responsible for producing infection-fighting lymphocytes.

Without treatment to restore immune function, children with Omenn syndrome typically do not survive past the age of 1 or 2.

Inheritance:

Omenn syndrome is inherited in an autosomal recessive manner. This means that a person must inherit two copies of the mutated gene, one from each parent, to develop the condition. The parents, who each carry one copy of the mutated gene, are usually asymptomatic carriers.