Characterization of the translocation breakpoint on chromosome 22q12.2 in a patient with neurofibromatosis type 2 (NF2).

We previously described a patient with neurofibromatosis type 2 (NF2) who showed a constitutional balanced translocation, t(4;22). To characterize the breakpoint on chromosome 22 in this patient in relation to a candidate gene (NF2) responsible for NF2, we analyzed DNAs from this patient and her parents using parts of NF2 cDNA as probes. Southern analyses and DNA sequencing revealed that the chromosome 22 breakpoint in this patient lies within the intron between exons 14 and 15 of NF2. The results lend support to the conclusion that NF2 is the gene responsible for the CNS form of neurofibromatosis.