. DEFECTS OF ADAPTIVE IMMUNITY .
Agammaglobulinemia refers to a small group of primary antibody deficiencies characterized by a severe reduction of all immunoglobulin classes due to the absence of peripheral B cells. There are at least 8 forms of agammaglobulinemia depending on which gene is defective. However, the common underlying pathological mechanism is a maturation failure of B lymphocyte precursors into differentiated B lymphocytes and, ultimately, plasma cells. Hence, immunoglobulins cannot be produced due to the lack of circulating mature B cells. X-linked agammaglobulinemia (XLA), caused by BTK mutations, explains most of the cases.
- Bacterial infections
- Onset: neonatal, infancy, childhood
- 1:100,000 – 1:200,000 (XLA)
Service benefits and management
- Differential diagnosis: CVID, SCID, HIGM, IgA def.
- Genetic counselling
- Ig replacement (IVIG)
- Antibiotic prophylaxis
- Avoid live vaccines
BLNK, BTK, CD79A, CD79B, IGHM*, IGKC*, IGLL1, LRRC8A, PIK3R1, TCF3
*These genes will be sequenced by a complementary technique