SCID Overview
SCID or Severe Combined Immunodeficiency is a group of very rare and potentially fatal inherited disorders of the immune system.
SCID is a defect in the specialized white blood cells (B- and T-lymphocytes). These cells defend the body from infection by viruses, bacteria, and fungi. Without a functional immune system, SCID patients are susceptible to infections such as pneumonia, meningitis and chicken pox, and can die before the first year of life. Though invasive, new treatments like bone marrow and stem-cell transplants save as many as 80% of SCID patients.
There is no record of how many babies are diagnosed with SCID in the United States each year, but the best estimate recognizes somewhere around 40-100. Therefore, SCID is a rare condition. On the other hand, researchers have no clear idea of how many babies are not diagnosed and die of SCID-related infections each year. The actual number of cases could be higher.
The most common form of Severe combined immunodeficiency has an x linked recessive pattern of inheritance. This type of SCID is called x-linked SCID. It is most commonly found in males, when the gene is located in the X chromosome. Males cannot compensate for their x chromosome because they only carry one. That means males only need one copy of the gene to have the disorder. On the other hand, females have two X chromosomes, if they inherit one defective chromosome they can still have a healthy pair. This means that they do not develop the disorder. Unfortunately, the faulty gene can still be carried and can be passed onto their children if their male partner also contributes the faulty gene in his X chromosome.
SCID or Severe Combined Immunodeficiency is a group of very rare and potentially fatal inherited disorders of the immune system.
SCID is a defect in the specialized white blood cells (B- and T-lymphocytes). These cells defend the body from infection by viruses, bacteria, and fungi. Without a functional immune system, SCID patients are susceptible to infections such as pneumonia, meningitis and chicken pox, and can die before the first year of life. Though invasive, new treatments like bone marrow and stem-cell transplants save as many as 80% of SCID patients.
There is no record of how many babies are diagnosed with SCID in the United States each year, but the best estimate recognizes somewhere around 40-100. Therefore, SCID is a rare condition. On the other hand, researchers have no clear idea of how many babies are not diagnosed and die of SCID-related infections each year. The actual number of cases could be higher.
The most common form of Severe combined immunodeficiency has an x linked recessive pattern of inheritance. This type of SCID is called x-linked SCID. It is most commonly found in males, when the gene is located in the X chromosome. Males cannot compensate for their x chromosome because they only carry one. That means males only need one copy of the gene to have the disorder. On the other hand, females have two X chromosomes, if they inherit one defective chromosome they can still have a healthy pair. This means that they do not develop the disorder. Unfortunately, the faulty gene can still be carried and can be passed onto their children if their male partner also contributes the faulty gene in his X chromosome.