Samples from patients with antibody deficiency were analyzed to determine BTK expression, immunophenotyping and mutation analysis. Clinical and laboratory data was analyzed and presented for each patient.
Most patients presented here showed atypical clinical and laboratory data for XLA, including normal IgM, IgG, or IgA levels. Most patients expressed detectable BTK protein. Sequencing of BTK showed that these patients harbored missense mutations in the pleckstrin homology and Src-homology-2 domains. When it was compared to public databases, BTK sequencing exhibited a new change, along with three other previously reported changes.
Delayed diagnosis and atypical manifestations in XLA might be related to mutation type and BTK expression.