The identification of Y chromosome translocations following Distamycin A treatment

Pretreatment of PHA-stimulated lymphocyte cultures from normal males with 100 micrograms/ml Distamycin A for the final 24 h of incubation led to a striking decondensation of the heterochromatic portion of the long arm of the Y chromosome. The despiralized region of Yq maintained its fluorescent properties in this altered morphologic state. Two cases of Y chromosome translocation (Y/22 and Y/X) were identified with this technique. A review of the literature revealed 62 similar cases in which the phenotypic-karyotypic correlations were instrumental in the prenatal counseling of the family with the Y/22 translocation.