Their tonsils and adenoids are often missing. Patients with XLA have extremely low levels of mature B cells. This gene normally produces a protein called btk, which is required for B-cell development. Approximately one in every million people develop SCID, a group of inherited disorders. People with SCID have severe abnormalities in both B and T cell immunity.
Babies typically have symptoms within the first three months of life.
They usually get numerous, serious or life-threatening infections, especially pneumonia, meningitis, and sepsis. Common infections like chickenpox, measles, or cold sores can overwhelm the patient's immune system. The doctor will order tests to measure immune function. Because ongoing infections can interfere with results, tests may have to be repeated several times. Patients usually have a very low number of white blood cells or lymphocytes, as well as few or no B and T cells.