Mapping of the del(5q) in 5q− syndrome patients.

FISH studies (patients 1-15) (A) and gene-dosage studies (patient 16) (B) with the use of probes from 5q31-qter and 5q13. The + indicates retained on del(5q); + ^R, rearranged on del(5q); −, deleted from del(5q); ND, not determined owing to limited metaphase numbers; boxed area, 5q− syndrome CDR. The following indicate that the probe was donated by the people or institutions listed:^a, Kay Davies, Oxford University; ^b, Jaju et al4; ^c, Kostrzewa et al9;^d, http://www.tree.caltech.edu/ and LBNL; ^e, National Institutes of Health and Institute of Molecular Medicine Collaboration.10 The 1-16 are 5q− syndrome (MDS-RA) cases studied; patient 4 has been reported previously.4 (C) Southern blot hybridized to a GLRA1 PCR probe showing rearrangement of the GLRA1 gene in patient 16. Previously published primers14 were used for the amplification of theGLRA1 gene, and the PCR-generated probe was sequenced to confirm its identity. The restriction enzymes used are indicated above the lanes. G indicates granulocyte DNA from patient 16; T, T-lymphocyte DNA from patient 16; C, peripheral blood DNA from healthy control. Rearranged fragments are observed in all 4 lanes containing granulocyte DNA from patient 16 (arrows), but not in T-lymphocyte DNA from patient 16, or in DNA from controls. No additional hybridization fragments were observed in the DNA tracks of patient 16 when the same Southern blot was rehybridized with each of the probes for the other 5q-specific genes investigated (see gene-dosage discussion in text).