Gene segment usage and CDR3 length of bone marrow-derived IGH gene rearrangements of NBS patients and controls. Frequency of V_H (A), D_H (B), and J_H (C) gene segment usage was determined in complete IGH gene rearrangements as amplified from bone marrow mononuclear cells. In total, 257 and 265 IGH gene rearrangements were analyzed in 5 different healthy controls and 10 NBS patients, respectively. (D) The length of the CDR3 regions was determined in the IGH gene rearrangements of healthy controls (n = 284) and NBS patients (n = 221) and did not show a difference.