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目的报道1例Wolf-Hirschhorn综合征携带1条环状4号染色体合并严重少精子症的病例,并探讨精子发生障碍的可能机制。方法为检测患者初级精母细胞染色体的联会、重组和转录失活情况,用荧光标记联会复合体蛋白3(synaptonemal complex protein 3,SCP3)、错配修复基因蛋白(mut L homolog 1,MLH1)和乳腺癌易感基因1(breast cancer susceptibility gene 1,BRCA1)蛋白对睾丸活检样本进行免疫荧光染色。结果 SCP3染色显示对照组偶线期精母细胞占5.2%,而患者偶线期的精母细胞显著增高占35.4%,表明患者的生精阻滞在初级精母细胞的偶线期。MLH1染色显示每个细胞的结合位点数对照组为47.8±4.5,患者为45.9±5.9,后者明显减少(U=2.62,P<0.05)。BRCA1染色显示患者所有粗线期细胞中都带有1条环状4号染色体,并有不同程度的不配对区域。结论环状4号染色体可能影响生殖细胞减数分裂Ⅰ期的进展,影响联会复合体的形成及未联会区域基因转录的活性,从而使精子的生成障碍,导致不育。
Objective To report a case of Wolf-Hirschhorn syndrome carrying one circular chromosome 4 combined with severe oligospermia, and to explore the possible mechanism of spermatogenesis disorder. Methods To detect the association, recombination and transcriptional inactivation of primary spermatocytes in patients, the expression of synaptonemal complex protein 3 (SCP3), mut L homolog 1 (MLH1 ) And breast cancer susceptibility gene 1 (BRCA1) protein were immunofluorescently stained for testicular biopsy samples. Results SCP3 staining showed that in the control group, the number of spermatocytes was even at 5.2%, while the number of spermatocytes at the even stage was 35.4%, indicating that the patient’s spermatogenic arrest was in the even stage of primary spermatocytes. MLH1 staining showed that the number of binding sites per cell was 47.8 ± 4.5 in control group and 45.9 ± 5.9 in patients, the latter was significantly decreased (U = 2.62, P <0.05). BRCA1 staining showed that all patients with pachytene cells with a circular chromosome 4, and have varying degrees of unpaired region. Conclusion Cyclic chromosome 4 may affect the progress of stage Ⅰ in meiotic division of germ cells, affect the formation of synaptonemal complex and the activity of gene transcription in the unlinked area, thus resulting in the formation of sperm disorder and infertility.