Bruton Tyrosine Kinase, BTK Full Gene Analysis, Varies

Clinical Use

Use

This test is useful for confirming a diagnosis of X-linked agammaglobulinemia in patients with a history of recurrent sinopulmonary infections, profound hypogammaglobulinemia, and less than 1% peripheral B cells, with or without abnormal Bruton tyrosine kinase (BTK) protein expression by flow cytometry. It also evaluates for the presence of BTK variants in family members of affected individuals, including those who do not demonstrate carrier phenotype by BTK flow cytometry. Identification of a disease-causing variant can assist with diagnosis, prognosis, clinical management, recurrence risk assessment, familial screening, and genetic counseling.

Special Instructions

Not provided.

Limitations

Next-generation sequencing may not detect all types of genomic variants, and in rare cases, false-negative or false-positive results may occur. There may be regions of BTK that cannot be effectively evaluated by sequencing or deletion and duplication analysis due to technical limitations. The test is not designed to detect low levels of mosaicism or differentiate between somatic and germline variants. The laboratory does not systematically review previously classified variants regularly. Reclassification of variants might occur based on the broadening genetic knowledge.

Test Details

New York Approved