Bruton type agammaglobulinemia

Affected individuals are males who have an increased susceptibility to bacterial infections due to severely reduced immunoglobulins of all isotypes. The underlying cause of XLA is an arrest of B-cell differentiation, which leads to an extreme deficiency of mature B lymphocytes (<1% of the normal value) and an absence of plasma cells. The age of onset of infections is generally around 6-12 months, with the average age of diagnosis at 3 years. Infections originating in mucosal surfaces are common in patients with XLA, and they may progress to the blood or other organs if left untreated. Pneumonia, meningitis, septic arthritis, cellulitis and septicemia can be seen in patients with XLA. Affected individuals may have an increased risk of colorectal cancer. Treatment entails immunoglobulin replacement and antibiotics. Female carriers are usually asymptomatic and have skewed X inactivation in B cells corresponding to expansion of only those B cells that use the normal BTK allele.

Tests Available

Forms and Documents

Test Details

BTK
  • Confirmation of clinical diagnosis
  • Distinguish among the various forms of primary immunodeficiency
  • Determination of appropriate treatment, including instituting prophylaxis
  • Carrier testing in female relatives of affected males
  • Prenatal diagnosis in at-risk pregnancies
  • Capillary Sequencing
  • Exon Array CGH

Ordering

154
3 weeks
2-5 mL Blood - Lavender Top Tube
Oral Rinse (30-40 mL)|Buccal Swabs

Billing

81406x1, 81479x1
No
Yes
  • 279.04 Congenital hypogammaglobulinemia, Agammaglobulinemia: Bruton's type X-linked
  • 279 Disorders involving the immune mechanism
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References

  1. Conley ME et al, 2005, Genetic analysis of patients with defects in early B-cell development, Immunological Reviews 203:216.
  2. Mutations of the human BTK gene coding for Bruton tyrosine Kinase in X-linked agammaglobulinemia, 1999, Vihinen, M et al, Human Mutation 13:280-285.