DUAL-COLOR FLUORESCENCE IN-SITU HYBRIDIZATION TO INVESTIGATE ANEUPLOIDY IN SPERM FROM 33 NORMAL MALES AND A MAN WITH A T(2,4,8)(Q23,Q27,P21)

Objective: To establish the relative frequency of aneuploidy in sperm from normal and abnormal subjects using dual color fluorescence in sit u hybridization and probes for six different chromosomes. Design: Seme n from 33 normal males and a patient with a translocation was studied using dual color fluorescence in situ hybridization with probes for ch romosomes 4, 7, 8, 12, 18, X and Y. The frequency of aneuploidy for ea ch chromosome is compared with one another and with the patient who ha d a t(2;4;8)(q23;q27;p21). Setting: Specimens were obtained from patie nts at the Mayo Clinic, Rochester, Minnesota. Results: The percentage of sperm with disomy or nullisomy in normal subjects ranged from 0.2% to 0.6% for each of the chromosomes studied. No statistically signific ant differences were observed between these chromosomes. The frequency of aneuploidy in sperm from a patient with at(2;4;8) was 3.3% and 4.8 % for chromosomes 4 and 8, respectively. Conclusion: Fluorescence in s itu hybridization was useful to establish the normal range of nullisom ic and disomic sperm for six different chromosomes and to study a pati ent with a clinically significant chromosome abnormality. In normal ma les, no difference in the frequency of meiotic nondisjunction was obse rved among the chromosomes studied.