Segregation analysis of four translocations, t(2;18), t(3;15), t(5;7), and t(10;12), by sperm chromosome studies and a review of the literature.
We examined the meiotic segregation patterns of 444 sperm cells belonging to four reciprocal translocation carriers, t(2;18)(p21;q11.2), t(3;15)(q26.2; q26.1), t(5;7)(q13; p15.1), and t(10;12)(q26.1;p13.3). For the t(2;18) carrier, the frequencies of alternate, adjacent-1, adjacent-2, and 3:1 segregations were 41.9%, 35.2%, 14.4%, and 8.4%, respectively. For the t(3;15) carrier, the segregation pattern was 48% alternate, 36% adjacent-1, 12% adjacent-2, 2% 3:1, and 2% 4:0. One cell was the result of a 4:0 segregation. For the t(5;7) heterozygote, the corresponding segregation frequencies were 40.2%, 26.2%, 16.6%, and 17.0%. This translocation heterozygote showed a higher number of 3:1 segregations than adjacent-2 segregations, which is unusual. The t(10;12) segregations were 61.1%, 26.3%, 6.9%, and 5.6%. The percentages of chromosome abnormalities unrelated to the translocation ranged from 0% to 0.6% for aneuploidy and from 5.5% to 10.9% for structural abnormalities. These frequencies are within the ranges for control donors. Sperm chromosome data from the literature on the segregation of 30 reciprocal translocations were reviewed.
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Division of Medical Genetics, West Penn Hospital, Pittsburgh, PA, USA.
Van Kirk
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Cieply
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D000328:Adult; D002874:Chromosome Mapping; D002877:Chromosomes, Human / Q000235:genetics*; D002879:Chromosomes, Human, Pair 10; D002881:Chromosomes, Human, Pair 12; D002884:Chromosomes, Human, Pair 15; D002887:Chromosomes, Human, Pair 18; D002889:Chromosomes, Human, Pair 2; D002893:Chromosomes, Human, Pair 3; D002895:Chromosomes, Human, Pair 5; D002897:Chromosomes, Human, Pair 7; D006801:Humans; D007621:Karyotyping; D008297:Male; D013094:Spermatozoa / Q000737:chemistry*; D014178:Translocation, Genetic