Heteroduplex PCR analysis in several IgH⁻MM patients to distinguish between polyclonal and monoclonalIGH and IGK gene rearrangements.

Clonal homoduplexes found with particular primer combinations are illustrated as compared to positive controls. In patient MM-1, the size of the homoduplex found with the V_h1-J_h PCR was essentially larger than predicted. Sequence analysis showed a PCR product with a V_h1-24/J_h3 rearrangement extended to the J_h5 segment with extensive somatic hypermutation of the J_h3 gene (resulting in loss of the primer annealing site) and deletion of the J_h4 segment most probably owing to an abnormal somatic mutation process.48