Dam A H D M, Feenstra I, Westphal J R, Ramos L, van Golde R J T, Kremer J A M
Department of Obstetrics and Gynaecology, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands.
Hum Reprod Update. 2007 Jan-Feb;13(1):63-75. doi: 10.1093/humupd/dml047. Epub 2006 Sep 28.
Globozoospermia is a rare (incidence <0.1%) but severe disorder in male infertility. Total globozoospermia is diagnosed by the presence of 100% round-headed spermatozoa lacking an acrosome. It is still unclear whether patients whose ejaculate contains both normal and globozoospermic cells (partial globozoospermia) suffer from a variation of the same syndrome. Apart from the fact that affected males suffer from reduced fertility or even infertility, no other physical characteristics can be associated with the syndrome. ICSI is a treatment option for these patients, although low fertilization rates after ICSI show a reduced ability to activate the oocyte. In globozoospermic cells, the use of acrosome markers has demonstrated an absent or severely malformed acrosome. Chromatin compaction appears to be disturbed but is not consistently over- or undercondensed. In some cases, an increased number of cells with DNA fragmentation have been observed. The analysis of the cytogenetic composition revealed an increased aneuploidy rate in some cases. Nonetheless, no increased number of spontaneous abortions or congenital defects has been reported in pregnancies conceived after ICSI. The pathogenesis of globozoospermia most probably originates in spermiogenesis, more specifically in acrosome formation and sperm head elongation. In several knockout mouse models, a phenotype similar to that in humans was found. Together with the occurrence of affected siblings, these findings indicate a genetic origin, which makes globozoospermia a good candidate for genetic analysis. More research is needed to elucidate the pathogenesis of human globozoospermia to further understand globozoospermia as well as (abnormalities in) spermiogenesis and spermatogenesis in general.
圆头精子症是男性不育中一种罕见（发病率<0.1%）但严重的病症。完全圆头精子症通过存在100%缺乏顶体的圆头精子来诊断。目前仍不清楚射精中同时含有正常和圆头精子细胞的患者（部分圆头精子症）是否患有同一综合征的变异型。除了受影响的男性生育力降低甚至不育这一事实外，该综合征没有其他相关的身体特征。卵胞浆内单精子注射（ICSI）是这些患者的一种治疗选择，尽管ICSI后受精率低表明激活卵母细胞的能力下降。在圆头精子细胞中，使用顶体标记物已证明顶体缺失或严重畸形。染色质浓缩似乎受到干扰，但并非始终过度或不足浓缩。在某些情况下，已观察到DNA片段化细胞数量增加。细胞遗传学组成分析显示在某些情况下非整倍体率增加。尽管如此，在ICSI后受孕的妊娠中，尚未报告自然流产或先天性缺陷数量增加。圆头精子症的发病机制很可能起源于精子形成过程，更具体地说是在顶体形成和精子头部伸长过程中。在几个基因敲除小鼠模型中，发现了与人类相似的表型。连同患病同胞的出现，这些发现表明其遗传起源，这使得圆头精子症成为遗传分析的良好候选对象。需要更多研究来阐明人类圆头精子症的发病机制，以进一步了解圆头精子症以及一般的精子形成和精子发生（异常情况）。
