As a common variation in the azoospermia factor c (AZFc) region of Y chromosome, the gr/gr deletion is regarded as a significant risk factor for spermatogenic impairment, whereas the association of the deletion's phenotypic expression with Y-chromosomal background is still a subject of debate. To further investigate the contribution of the deletion to spermatogenic impairment in different Y-chromosomal haplogroups, the partial AZFc deletion was detected with AZFc-specific sequence tagged sites, gene dosage and gene copy analyses of deleted in azoospermia (DAZ), chromodomain Y1 (CDY1) and basic protein Y2 (BPY2) in 1426 azoo/oligozoospermic and 672 normozoospermic men from a Chinese population. The haplogrouping was performed in 231 deletion carriers with 12 polymorphic loci of Y chromosome. As a result, five gr/gr rearrangement types in eight Y haplogroups were observed, in which the simple gr/gr deletion was the most common type, and its frequency was significantly higher in men with azoo/oligozoospermia relative to normozoospermia. Also the distribution of gr/gr-rearranged Y haplogroups was significantly different between the two groups, in which gr/gr-deleted haplogroups C and DE were more common in men with azoo/oligozoospermia. In the 6 gr/gr copy deletion haplotypes, the frequencies of DAZ1/DAZ2+CDY1a or CDY1b deletion were significantly higher in men with azoo/oligozoospermia, while all DAZ3/DAZ4+CDY1b+BPY2.2 or 2.3 deletions were found only in haplogroup Q1 without any distribution difference between the azoo/oligozoospermic and normozoospermic groups. This study provided further evidence for the existence of multiple subtypes of gr/gr deletion and indicates that gr/gr-DAZ1/DAZ2 deletion is a significant risk factor. However, the association of the phenotypic variation of gr/gr deletion with Y-chromosomal haplogroups is not definite yet, because of the limited amounts of the deletions observed in each of the haplogroups and the lack of the quantitative trait analyses such as sperm density analysis. The fact that a common gr/gr copy deletion haplotype was found exclusively in the Y hgr Q1, without pathogenic consequences, implies the importance of haplogrouping and of copy deletion typing prior to genetic counselling of deletion carriers of Chinese descent.

The acrosome reaction has long been thought to be induced by the zona pellucida. Here we report the identification and function of a novel human sperm glycosylphosphatidylinositol (GPI)-anchored membrane protein, NYD-SP8. The release of the protein during sperm-egg interaction and its binding to the cumulus, the first layer of egg investment, elicits cross-talk between the gametes and produces calcium dependant release of progesterone, which lead to the acrosome reaction. An in vivo mouse model of NYD-SP8 immunization is also established showing a reduced fertility rate. Thus, contrary to accepted dogma, our study demonstrates for the first time that, prior to reaching the zona pellucida, sperm may release a surface protein that acts on the cumulus cells leading to the acrosome reaction, which may be important for determining the outcome of fertilization.

This study provides evidence for the association of Y-chromosome background with impaired spermatogenesis, suggesting that Y variations play a role in the occurrence and even the severity of spermatogenic failure. Furthermore, both AZFc deletions and other Y-chromosome structural variations may be important for determining the susceptibility to spermatogenic failure. Our findings emphasise the necessity of more extensive study on Y-chromosome variations for better understanding of spermatogenesis and its pathology.

Dopa-responsive dystonia (DRD) is typically caused by heterozygous mutations in GTP cyclohydrolase 1 gene (GCH1). Our aim was to investigate the clinical and genetic features of Chinese DRD patients. We analyzed a cohort of Chinese DRD patients' clinical data. Mutation of the GCH1 gene was screened by direct sequencing. Additionally, multiplex ligation-dependent probe amplification (MLPA) assay targeting the GCH1 and the TH gene to evaluate large exon deletion or duplicate mutation of the genes were performed in point mutation-negative patients. Ten sporadic DRD patients and two pedigrees including six patients were included in the study. The onset age ranged from 3 to 15 years old. All patients initially presented with walking problems due to lower limb dystonia. The delay between onset and diagnosis ranged from 1 to 42 years old. The symptoms were completely or near-completely abolished with low dose levodopa treatment (dosages ranged from 25 mg to 400 mg/day). Direct sequencing in 14 patients found two known mutations (Gly203Arg in exon 5 in four unrelated patients and Met102Lys in exon 1 in one patient) and one new mutation (Thr186Ile mutation in exon 5 in two unrelated pedigrees). A heterozygous exon 2 deletion in the GCH1 gene was found in one of three point mutation-negative patients by MLPA analysis. Our clinical findings in DRD patients were consistent with other studies. GCH1 gene mutations were quite common in Chinese patients. MPLA should be performed in routine deletion analysis of GCH1 in point mutation-negative DRD patients.

The findings indicate that some monophyletic Y chromosomes may be associated with predisposition to specific subtypes of partial AZFc deletion and adverse effect on spermatogenesis. Although these deletions were not confirmed with gene dosage analysis, the results suggest that Y chromosome background is an important factor that affects partial AZFc deletion formation and its contribution to spermatogenic failure.