小的超数标记染色体(sSMC)被定义为结构异常的染色体,很难通过常规的细胞遗传学技术来鉴定。sSMC在不育男性中的患病率是普通人群的3.75倍。这项研究旨在表征非近亲不育夫妇中的多余标记染色体,并通过多色FISH分析其在精子中的减数分裂分离。男性伴侣的核型是mos47,XY,+idic(15)(pter→q11.1::q11.1→pter)[6]/46,XY[24]。ishidic(15)(NOR+,D15Z3+,SNRPN-,D15Z3+,NOR+)。在使用CEP15、BAC15和BAC21探头的三重FISH中,分析了患者的4,227个精子,sSMC仅在0.66%的精子中检测到。在采用CEPX的三重FISH中,CEPY,和BAC18探头,分析患者的2,008个精子。二体和二倍体精子的频率与对照供体没有显着差异。据我们所知,据报道,只有9名具有非马赛克核型的男性分离了sSMC15。这些研究描述了sSMC15的精子率在6.23%至50%以上的范围内。在这项工作中,我们报道了1例镶嵌核型患者精子中15号染色体来源的sSMC的首次减数分裂分离分析.检测到sSMC的精子率低与我们患者淋巴细胞中异常细胞的比例低一致。此外,这种sSMC干扰其他染色体的风险似乎很小.建议进行遗传咨询,因为与父系sSMC相关的胎儿染色体失衡的风险非常低。最后,一个健康的男孩在自然怀孕后出生。
Small supernumerary marker chromosomes (sSMCs) are defined as structurally abnormal chromosomes that are difficult to identify by conventional cytogenetic techniques. sSMCs are 3.75 times more common in infertile men than in the general population. This study aimed at characterizing a supernumerary marker chromosome in a nonconsanguineous infertile couple and analyzing its meiotic segregation in sperm by multicolor FISH. The male partner\'s karyotype was mos 47,XY,+idic(15)(pter→q11.1::q11.1→pter)[6]/46,XY[24].ish idic(15)(NOR+,D15Z3+,SNRPN-,D15Z3+,NOR+). In triple FISH using CEP 15, BAC 15, and BAC 21 probes, 4,227 spermatozoa of the patient were analyzed, and the sSMC was detected in only 0.66% of spermatozoa. In triple FISH employing CEP X, CEP Y, and BAC 18 probes, 2,008 spermatozoa of the patient were analyzed. The frequency of disomic and diploid sperm was not significantly different from control donors. To our knowledge, segregation of an sSMC 15 has been reported in only 9 males with non-mosaic karyotypes. These studies described rates of spermatozoa with sSMC 15 ranging from 6.23% to more than 50%. In this work, we report the first meiotic segregation analysis of a chromosome 15-derived sSMC in spermatozoa of a patient with a mosaic karyotype. The low rate of spermatozoa with sSMC detected is concordant with the low proportion of abnormal cells in our patient\'s lymphocytes. Moreover, the risk of interference of this sSMC with other chromosomes seems minimal. Genetic counseling was recommended given that the risk of chromosomal imbalance in the fetus linked to paternal sSMC was very low. Finally, a healthy boy was born after a natural pregnancy.