MC antibody defect
A. Xlinked agammaglobulinemia
B. Bruton agammaglobulinemia
C. CVID
D. A and B
C. CVID
MC T-cell disorder
Chromosome 22q11.2 deletion
Most severe immunodeficiency
SCID
> absence of B and T cells
> persistently low lymphocyte counts
Distinguishing factor of Bruton agammaglobulinemia which differentiates it from Hyper IgM syndrome and CVID
Absent circulating B cells on flow cytometry