Exclusion mapping of the Cohen syndrome gene from the Prader-Willi syndrome locus.

[cohen syndrome]

Karyotype and DNA analyses using DNA probes were carried out in a family with the Cohen syndrome . Two affected brothers had normal chromosomal constitutions . A major deletion or duplication of genomic DNA fragments hybridized with the DNA probes , pML 34 at D 15 S 9 locus and pTD 3 -21 at D 15 S 10 locus , assigned on 15 q 11 -q 12 was not detected in the patients . In addition , a linkage of the syndrome to D 15 S 9 and D 15 S 10 loci was not observed in the family . These data suggest that a gene for the Cohen syndrome is excluded from the 15 q 11 -q 12 region , on which a gene for the Prader-Willi syndrome is assigned , and that the Cohen syndrome is distinctly different from the Prader-Willi syndrome , although clinical manifestations of the Cohen and the Prader-Willi syndromes are very similar .