New markers for the neurofibromatosis-2 region generated by microdissection of chromosome 22
To identify new DNA markers around the neurofibromatosis-2 gene on human chromosome 22, the critical region (22q12-q13.1) was microdissected and microcloned from GTG-banded metaphase chromosomes. Eighteen thousand recombinant clones were obtained. Twenty-seven of 55 clones tested (50%) detected single-copy DNA sequences. Nine of nine clones analyzed in detail were found to map to chromosome 22. Interestingly one clone (EAN04) is part of the leukemia inhibitory factor gene which has previously been mapped to 22q11.2-q13.1. Four clones (EAN01, EAN47, EAN57, and EAN68) detect DNA polymorphisms. These probes were used to compare constitutional and tumor genotypes of 41 patients with acoustic neurinoma. Loss of constitutional heterozygosity was identified in 17 of 31 informative cases (55%). From our data we conclude that the microdissection library is a valuable resource for physical and genetic mapping studies in neurofibromatosis-2.