We have previously described the cytogenetic analysis of two patients with Greig cephalopolysyndactyly syndrome (GCPS) and various microdeletions on the short arm of Chromosome (Chr) 7. Using genes and anonymous DNA probes from 7p we analyzed the DNA of our patients for loss of heterozygosity, or we determined the copy number by semi-quantitative Southern hybridization. We have been able to show hemizygosity for the genes of INHBA, IGFBP1 and GLI3 in both patients and therefore can give the chromosomal assignment 7p12.3-p13. CRI-R944 and CRI-P137 map to the same region, whereas CRI-S207 can be assigned to 7p13-p14.2; TM102L, TS93, TS194, TM77 and TN177 showed no change and these probes map distal to 7p14.2.