X-linked Agammaglobulinemia (XLA): BTK (Full Gene Sequencing)

Whole blood; DNA is accepted (Call 800-345-4363 for DNA collection information.)

2 mL

Lavender-top (EDTA) tube

Confirm a clinical diagnosis of XLA; detect carriers; allow early diagnosis in family members, guiding prophylactic measures

This method does not reliably detect mosaic variants; large deletions; large duplications, inversions, or other rearrangements; or deep intronic variants. It may be affected by allele-dropout, it may not allow determination of the exact numbers of T/A or microsatellite repeats, and it does not allow any conclusion as to whether two heterozygous variants are present on the same or on different chromosome copies.

Results of this test are for investigational purposes only. The performance characteristics of this assay have been determined by LabCorp. The result should not be used as a diagnostic procedure without confirmation of the diagnosis by another medically established diagnostic product or procedure.

DNA sequencing

Normal equals reference sequence or variants that are known or predicted to be benign; abnormal equals all other variants.

X-linked agammaglobulinemia (XLA), also know as Bruton's agammaglobulinemia, is a male-limited X-linked recessive immune disorder characterized by almost complete absence of mature B cells and thus the inability to produce immunoglobulins of any class. Patients experience increased susceptibility to bacterial infections and reduced ability to resolve infections with enteroviruses such as echo, coxsackie, or poliovirus, which can then lead to slowly progressing, fatal disease affecting the central nervous system. Mutations in BTK account for all XLA and about 85% of all primary defects in early B-cell development. Genetic testing can confirm a clinical diagnosis of XLA and detect mutation carriers within affected families.