DYZ1 copy number variation, Y chromosome polymorphism and early recurrent spontaneous abortion/early embryo growth arrest

ObjectivesTo find the association between recurrent spontaneous abortion (RSA)/early embryo growth arrest and Y chromosome polymorphism.Study designPeripheral blood samples of the male patients of big Y chromosome, small Y chromosome and other male patients whose partners suffered from unexplained RSA/early embryo growth arrest were collected. PCR and real-time fluorescent quantitative PCR were used to test the deletion and the copy number variation of DYZ1 region in Y chromosome of the patients. A total of 79 big Y chromosome patients (48 of whose partners suffered from RSA or early embryo growth arrest), 7 small Y chromosome patients, 106 other male patients whose partners had suffered from unexplained RSA or early embryo growth arrest, and 100 normal male controls were enrolled.ResultsThere was no fraction deletion of DYZ1 detected both in big Y patients and in normal men. Of RSA patients, 1 case showed deletion of 266 bp from the gene locus 25-290 bp, and 2 cases showed deletion of 773 bp from 1347 to 2119 bp. Of only 7 small Y chromosome patients, 2 cases showed deletion of 266 bp from 25 to 290 bp, and 4 cases showed deletion of 773 bp from 1347 to 2119 bp and 275 bp from 3128 to 3420 bp.The mean of DYZ1 copies was 3900 in normal control men; the mean in big Y patients was 5571, in RSA patients was 2655, and in small Y patients was 1059. All of the others were significantly different (P < 0.01) compared with normal control men, which meant that DYZ1 copy number in normal control men was less than that of big Y chromosome patients, and was more than that of unexplained early RSA patients and small Y patients.ConclusionsThe integrity and copy number variation of DYZ1 are closely related to the Y chromosome length under microscope. The cause of RSA/early embryo growth arrest in some couples may be the increase (big Y patients) or decrease of DYZ1 copy number in the husbands' Y chromosome.