Familial reciprocal translocation t(17;19) (q11.2;q13.2) associated with neurofibromatosis type 1, including one patient with non-Hodgkin lymphoma and an additional t(14;20) in B lymphocytes.

The cosegregation of a reciprocal translocation t(17;19) (q11.2;13.2) with neurofibromatosis type 1 in three generations suggested that the breakpoint on chromosome 17 involved the NF1 gene. In order to map the breakpoint, we analysed DNAs of patients using parts of the NF1 gene as probes. Southern analysis revealed that the chromosome 17 breakpoint lies within intron 23 of the NF1 gene. One of the patients of the family developed a non-Hodgkin lymphoma. An additional translocation t(14;20) (q32;13.1) in his B lymphocytes points to a gene on chromosome 20 that is juxtaposed to the IGH locus on 14q32, and that may be of relevance for the development of this tumor type.