Littérature scientifique sur le sujet « Regione AZFc »

The infertility affects about 15% of couples and male factors being responsible about 40-50%. In male infertility, genetic abnormalities of Y chromosome play crucial role in spermatogenesis defect. Y chromosome q arm having Azoospermia factor region (AZFa, AZFb, and AZFc) are most important for spermatogenesis. Here, we investigated the frequencies of Y-chromosome microdeletions using three sets of multiplex PCR in idiopathic cases of azoospermia. We studied a total of 110 infertile male with non-obstructive azoospermia subjects & 50 fertile control subjects. All DNA samples were used for Y chromosome microdeletions analysis by using 11 STS markers in three different multiplex PCR of AZF regions. Out of 110 infertile azoospermic males, 14 (12.72%) infertile males showed partial deletion of AZF regions using three sets of multiplex PCR group. In the AZF microdeletions of infertile males, individually AZFc region was the most deletions sites (10%) followed by AZFb (6.36%) and AZFa (1.81%). The sites and sizes of microdeletions differ in all infertile azoospermic males who showed at least two or more STS markers microdeletions. The frequency of Y chromosome microdeletions in our azoospermic infertile males is 12.72%. We conclude that Y chromosome microdeletions frequency in azoospermic infertile males is higher than other infertile group due to severe impairment in spermatogenesis. Multiplex PCR screening of microdeletions is very useful and time saving technique when used more number of STS markers. It will be great help to infertility clinics for genetic counseling and assisted reproduction.

To investigate the clinical, hormonal, and genetic factors in infertile men with idiopathic nonobstructive azoospermia (NOA) or azoospermic Klinefelter syndrome (KFS), a total of 556 and 96 patients, respectively, were included in this study. All patient samples were analyzed cytogenetically. Serum reproductive hormone levels were measured. Microdeletions in the azoospermia factor (AZF) region of the Y chromosome were detected by multiplex PCR using 16 specific sequence-tagged sites. FSH and LH levels in both NOA and KFS patients were significantly higher than the normal range, and the testosterone level in KFS patients was significantly lower. Ninety-two (95.8%) of the KFS patients showed non-mosaic 47,XXY karyotypes and 47,XXY,inv(9)(p11.1q13); the other KFS patients had mosaic karyotypes of 47,XXY/46,XY, 47,XXY/46,XX, and 47,XXY/48,XXXY/46,XX. Among the 556 idiopathic NOA patients with normal karyotypes, 67 (12.05%) had microdeletions in the AZF region of the Y chromosome. Microdeletions were most frequently detected in the AZFc region, followed by AZFa, AZFb, AZFbc, and partial AZFc deletions. However, Y chromosome microdeletions were not found in any of the azoospermic KFS patients. In view of the hormonal and genetic abnormalities in infertile men with idiopathic NOA and with azoospermic KFS, genetic testing for karyotype, Y chromosome microdeletions, and hormonal parameters is advocated.

Objectives To investigate azoospermic factor (AZF) microdeletions in infertile men from northeastern China with karyotypic Y chromosome abnormalities. Methods G-banding of metaphase chromosomes and karyotype analysis were performed in all infertile male patients. Genomic DNA was isolated and used to analyze classical AZF microdeletions by PCR. The regions and sequence-tagged sites of AZFa (SY86, SY84), AZFb (SY127, SY134, SY143), and AZFc (SY152, SY254, SY255, SY157) were sequenced by multiplex PCR. Results A total of 190 Y chromosome abnormality carriers were found, of whom 35 had AZF microdeletions. These were most common in 46,X,Yqh− patients, followed by 45,X/46,XY patients. Most microdeletions were detected in the AZFb + c region, including 48.57% of all AZF microdeletion cases. AZF partial deletions were also seen in these patients. Overall, AZF microdeletions were detected in 38.5% Y chromosome abnormality carriers, and most were observed in 46,X,Yqh− individuals. Loss of SY152 was seen in all 35 patients, with SY254/SY255 detected in 34 of 35 patients. Conclusions AZF microdeletions were detected in 38.5% of Y chromosome abnormality carriers. This indicates that AZF microdeletion screening is advisable for individuals with karyotypic Y chromosome abnormalities.

The azoospermia factor (AZF) regions consist of three genetic domains in the long arm of the human Y chromosome referred to as AZFa, AZFb and AZFc. These are of importance for male fertility since they are home to genes required for spermatogenesis. In this paper a comprehensive analysis of AZF structure and gene content will be undertaken. Particular care will be given to the molecular mechanisms underlying the spermatogenic impairment phenotypes associated to AZF deletions. Analysis of the 14 different AZF genes or gene families argues for the existence of functional asymmetries between the determinants; while some are prominent players in spermatogenesis, others seem to modulate more subtly the program. In this regard, evidence supporting the notion thatDDX3Y,KDM5D,RBMY1A1,DAZ, andCDYrepresent key AZF spermatogenic determinants will be discussed.

The mechanisms by which Y chromosome microdeletions cause infertility have been well described; however, the therapeutic targets remain a challenge. Here, we used whole-genome sequencing to explore the mechanism of Y chromosome deletion and potential therapeutic targets in a patient with infertility. There were no abnormalities in the patient’s medical history. Routine semen analysis showed immotile sperm and only two motile spermatozoa were occasionally see after centrifugation, indicating that the direct cause of infertility was an abnormal sperm count and motility. A Y chromosome microdeletion test revealed partial deletion of the AZFc region, including AZFc1, AZFc2, AZFc3, and AZFc4. Whole-genome sequencing showed that the patient had seven harmful mutations, with only one significant epigenetic mutation, SH3KBP1. Gene Ontology analysis of these meaningful mutations indicated involvement of cAMP signaling pathways. The patient’s wife became pregnant following in vitro fertilization, and no significant abnormalities were found during prenatal examination. This case suggests that Y chromosome microdeletion and gene mutation may affect the cAMP signaling pathway, leading to reduced sperm quality and male infertility.

Y chromosome micro-deletion (YCM) is a group of genetic diseases caused by missing gene (s) in specific regions of the Y chromosome. Many individuals with YCM show no manifestations and lead normal life. On the other hand, YCM is known to exist in a significant number of infertile males. Forty adult patients suffering from severe oligospermia and azoospermia were enrolled in the present study. Seminal fluid analyses were performed, and a blood sample was obtained for hormonal analysis and DNA extraction. Follicle stimulating hormone (FSH) and luteinizing hormone (LH) profiles were measured and those who are azoospermic with normal FSH levels were subjected to testicular biopsy. The results revealed that 23 patients were azoospermic while 17 patients were severe oligospermic. It is also shown that ten azoospermic patients had normal serum gonadotrophin levels thus they were directed for testicular biopsy. Histopathological examination of testicular biopsy showed that four patients had obstructive azoospermia while the remaining six suffered maturation arrest. DNA was extracted according to the standard proteinase K/phenol-chloroform method in the medical biotechnology laboratory/Scientific Research Center/University of Duhok. Multiplex PCR was performed for genes located in the azoospermia factor (AZF) regions (AZFa, AZFb, and AZFc) to detect any possible micro-deletions. Y chromosome micro-deletions were determined in 26 patients out of a total of 40 patients. Micro-deletions in the AZFc sub-region appeared in 16 out of 26 patients (61.5 %), and 10 (38.5 %) sample showed AZFb, however, AZFa micro-deletion was not detected in any of the patients. In conclusion, it has been found that Y chromosome micro-deletions in the AZF region can be a determining factor for male infertility and the resultant manifestations.

Microdeletions of Y chromosomes frequently occur in 3 subregions of the AZF, namely, AZFa, AZFb, and AZFc, with 6 basic STS marker sequences, which are sY84, sY86 (AZFa), sY127, sY134 (AZFb), and sY254, sY255 (AZFc). According to EAA/EMNQ guidelines, 11 additional AZFabc marker sequences should be used to determine the extent of the microdeletion in the AZF region of infertile men, which is known as 11 extended STSs. By applying mPCR, the authors develop an optimal detection procedure for the 6 basic STS and 11 extended STS using 3 multiplex PCR reactions. The first multiplex PCR reaction includes 6 basic STS plus the 2 control sequences sex-determining region Y (SRY) and zinc finger protein X/Y-linked (ZFX/Y). The second multiplex PCR reaction includes the 6 extended STS sY88, sY1182, sY105, sY121, sY1191, and sY1291 and the 2 control sequences SRY and ZFX/Y. The third multiplex PCR reaction includes the 5 extended STS sY153, sY160, sY82, sY143, and sY83 and the 2 control sequences SRY and ZFX/Y. Six basic primer sequences and eleven extended primer sequences are redesigned to simultaneously pair and amplify STS in the same multiplex reaction: set of 8 primers for 6 basic STS: 6 basic STS + 2 (SRY, ZFX/Y), 8 extension primers set E1: 6 extended STS + 2 (SRY, ZFX/Y), and 7 extension primers set E2: 5 extended STS + 2 (SRY, ZFX/Y). We successfully designed primer pairs with high specificity and stability and successfully amplified 6 basic STS and 11 extended STS, which ensures that the STSs have the correct sequence as recommended by EAA/EMQN and are consistent with the NCBI gene bank. This study has successfully developed a procedure to simultaneously detect 17 STSs, including 6 basic STSs and 11 extended STSs in the AZF region using 3 multiplex PCR reactions.

Objective The objective was to investigate the frequency and type of chromosomal abnormalities and Y chromosome microdeletions in infertile men with azoospermia and oligozoospermia to ensure appropriate genetic counseling before assisted reproduction in Eastern China. Methods A total of 201 infertile men (148 with azoospermia and 53 with oligozoospermia) were enrolled. Real-time PCR using six Y-specific sequence-tagged sites of the azoospermia factor (AZF) region was performed to screen for microdeletions. Karyotype analyses were performed on peripheral blood lymphocytes with standard G-banding. Results Out of 201 infertile patients, 22 (10.95%) had Y microdeletions [17/148 (11.49%) men with azoospermia and 5/53 (9.43%) men with oligozoospermia]. The most frequent microdeletions were in the AZFc region, followed by the AZFa+b + c, AZFb+c, AZFa, and AZFb regions. Chromosomal abnormalities were detected in 18.91% (38/201) of patients, 34 of which were sex chromosome abnormalities (16.92%) and 4 of which were autosomal abnormalities (1.99%). Chromosomal abnormalities were more prevalent in men with azoospermia (22.97%) than in those with oligozoospermia (7.55%). Conclusions We detected a high incidence of chromosomal abnormalities and Y chromosomal microdeletions in infertile Chinese men with azoospermia and oligozoospermia. These findings suggest the need for genetic testing before the use of assisted reproduction techniques.

ABSTRACT Men with severe infertility suffer a high risk of Y chromosome deletion, hence screening for these cases is recommended prior to treatment with assisted reproduction. Our study aimed to investigate and detect the azoospermia factor (AZF) region deletion, rearrangement and deleted azoospermia (DAZ) gene copy number variations in Egyptian azoospermic infertile men. This was tested on 54 Egyptian nonobstructive azoospermic (NOA) infertile men, with age ranged from 21 to 45 years (mean: 31.4 ± 6.1 years), by STS ± multiplex PCR using a set of 14 sequence tagged sites (STSs) from three different regions of the Y chromosome: AZFa, AZFb, AZFc and sY587/DraI PCRRFLP assay to determine DAZ copy number variations. The results revealed a significant prevalence of AZFc subtypes deletion and reduced DAZ gene dosage in Egyptian azoospermic cases affecting Y chromosome deletions. To our knowledge, this study is the first one to investigate AZFc subtypes deletion and DAZ gene dosage in Egyptian infertile men. We concluded that DAZ genes deletion is a risk factor for spermatogenic damage. How to cite this article Fayez AG, El-Sayed AS, El-Desouky MA, Zarouk WA, Kamel AK, Fahmi IM, El-Ruby MO. Molecular Characterization of Some Genetic Factors Controlling Spermatogenesis in Egyptian Patients with Male Infertility. Int J Infertility Fetal Med 2012;3(3):69-77.

<p><em>Tema y alcance:</em> el objetivo de esta revisión es conocer los estudios que se han hecho a nivel mundial sobre las microdeleciones del cromosoma Y y sus posibles efectos en los resultados genético forenses observados. <em>Características:</em> la infertilidad originada en el cromosoma Y es generalmente causada por deleciones del material genético en las zonas relacionadas con el Factor de Azoospermia (AZF), localizadas en tres regiones del Yq contiguas: AZFa, AZFb y AZFc. <em>Hallazgos:</em> se ha comprobado que algunos de los STRs utilizados rutinariamente en el laboratorio de genética forense con kits multiplex están localizados en estas regiones permitiendo evidenciar la existencia de microdeleciones en algunos loci. Aumentar el conocimiento de los eventos microestructurales dentro del cromosoma Y puede ser de utilidad para una mejor caracterización de los patrones anormales repetitivos que complican la interpretación del perfil de ADN. <em>Conclusiones: </em>la variación en estudios poblacionales de prevalencia de microdeleciones, puede deberse a diferencias en la selección de los pacientes, tamaño muestral, la técnica usada. Los casos reportados concluyen que los loci afectados generalmente son DYS385, DYS392 indican microdeleciones en la región AZFb y DYS448 está relacionado con microdeleciones en la región AZFc.</p>

A infertilidade é um problema de saúde pública com um significativo impacto social, econômico e psicológico. Em todo o mundo, a incidência da infertilidade entre a população geral é estimada em 10-15%. Cerca de 50% da infertilidade dos casais são de origem masculina. Em mais da metade dos homens inférteis, a causa da infertilidade é desconhecida (idiopática). Etiologicamente, a infertilidade masculina apresenta causas genéticas e não genéticas. Dentre as causas genéticas mais conhecidas temos mutação do receptor de andrógenos, mutação do gene regulador da condutibilidade transmembrana da fibrose cística (CFTR), anomalias cromossômicas clássicas, anomalias meióticas, microdeleções do cromossomo Y, etc. As anomalias cromossômicas são encontradas com muito mais frequência em homens inférteis, com uma incidência de 4-16% em relação à incidência de 0,4% na população fértil. Estudos mostram que as CNVs também podem estar relacionadas com a infertilidade masculina, especificamente com a falha na espermatogênese. CNVs encontradas tanto no cromossomo Y quanto nos cromossomos autossômicos também foram associadas a possíveis falhas na espermatogênese. Um outro fator que também pode estar envolvido com a infertilidade masculina é a expressão desregulada dos miRNAs. O presente trabalho teve como objetivo promover a análise em larga escala da distribuição de CNVs e do perfil transcricional dos miRNAs em amostras de biopsias testiculares de paciente com azoospermia. Para o estudo das CNVs nós utilizamos a metodologia do CytoScan HDTM da Affymetrix. O perfil transcricional de miRNAs nos indivíduos estudados foi avaliado por meio da tecnologia de microarranjos também da plataforma Affymetrix. Para estas analises montamos dois grupos de estudo (Parada de Maturação (MA) de Células Germinativas e Síndrome de Células Sertoli Only (SCOS)) e um grupo controle (azoospermia obstrutiva e espermatogênese normal). Através das análises das CNVs nós encontramos 94 CNVs nos cromossomos autossômicos e sexuais, 35 (37%) CNVs foram classificadas como benignas, 24 (23%) como potencialmente benignas, sete CNVs (7,4%) como patogênicas e sete foram classificadas como potencialmente patogênica. Todas as CNVs classificadas como patogênica estão presentes no cromossomo Y, cinco CNVs são do tipo duplicação e duas do tipo deleção. A CNV do tipo duplicação foi encontrada no paciente MA e a CNV do tipo deleção foi encontrada no paciente SCOS. As CNVs se sobrepõem e quando analisadas em conjunto (formando uma única CNV de cada condição) elas apresentam um tamanho parecido. Estas CNVs apresentam genes envolvidos na espermatogênese. As CNVs classificadas como potencialmente patogênicas estavam presentes nos cromossomos autossômicos e cromossomo X. Nestas CNVs estavam presentes genes que foram associados com a falha na espermatogênese. A análise da expressão dos miRNAs revelou um perfil transicional muito mais alterado nos pacientes com SCOS. As duas condições apresentaram miRNAs exclusivos, mas também compartilharam: 30 miRNAs. Nós identificamos duas famílias de miRNAs (miR449 e miR34) diferencialmente expressos nas duas condições e que apresentam expressão preferencial no testículo. Nossos resultados mostram que alterações no número de copias (CNVs) no cromossomo Y levam a infertilidade masculina e CNVs nos cromossomos autossômicos e X podem levar a infertilidade masculina. As alterações do tipo deleção podem levar a uma falha na espermatogênese maior que as alterações do tipo duplicação. A expressão diferencial dos miRNAs em tecido testicular de pacientes com diferenças histopatológicas (SCOS e MA) apresentam um padrão de expressão de miRNAs diferentes devido ao tipo de células germinativas que eles apresentam no tecido epitelial do testículo.
Infertility is a public health problem with significant social, economic and psychological impact. Worldwide, the incidence of infertility in the general population is estimated at 10- 15%. Approximately 50% of infertility of couples is of male origin. In more than half of infertile men, the cause of infertility is unknown (idiopathic). Etiologically, male infertility has genetic and non-genetic causes. Among the best known genetic causes we found the mutation of the androgen receptor, the cystic fibrosis transmembrane conductance regulator (CFTR), classic chromosomal abnormalities, meiotic abnormalities and microdeletions of the Y chromosome. Chromosomal abnormalities are found much more frequently in infertile men, with an incidence of 4-16% in the incidence of 0.4% in the fertile population. Studies show that CNVs can also be related to male infertility, specifically in the failure of spermatogenesis. CNVs found in both the Y and autosomes chromosomes were also associated with possible failures in spermatogenesis. Another factor that may also be involved in male infertility is the deregulated expression of miRNAs. This work aimed to promote the analysis of large-scale distribution of CNVs and the transcriptional profile of miRNAs in testicular biopsy samples from patients with azoospermia. For the study of CNV we used the CytoScan HDTM Affymetrix methodology and the transcriptional profile of miRNAs in the samples was assessed by means of microarray technology from Affymetrix platform. For these analyzes we set up two study groups (Stop Maturation (MA) of Germ Cells and Sertoli Cell Only Syndrome (SCOS)) and compared them to a control group (obstructive azoospermia, normal spermatogenesis). Through analysis of CNVs, we found 94 CNVs in sexual and autosomes chromosomes, 35 (37%) were classified as benign CNVs, 24 (23%) as a potentially benign seven CNVs (7.4%) as pathogenic and 7 were classified as potentially pathogenic. All CNVs classified as pathogenic are present on the Y chromosome, five CNVs are of duplication type and two are deletion type. The duplication type CNV was found in MA patients and deletion type CNV was found in SCOS patient. We identified that CNVs overlap and when analyzed jointed - as a single CNV of each condition - they have a similar size. These CNVs have genes involved in spermatogenesis. CNVs classified as potentially pathogenic were present in autosomes and in the X chromosome. In these CNVs were present genes that were associated with failure in spermatogenesis. The analysis of the expression of miRNAs revealed a transitional profile much more altered in patients with SCOS. The two conditions presented exclusive miRNAs, but shared 30 miRNAs differentially expressed when compared to the control group. We identify two families of miRNAs (miR449 and miR34) which exhibit preferential expression in testis as differentially expressed in both conditions. Our results show that changes in the number of copies (CNVs) on the Y chromosome lead to male infertility and CNVs in autosomes and X chromosomes may lead to male infertility. The deletion type changes can lead to a failure of spermatogenesis greater than the duplication type changes. The differential expression of miRNAs in patients with testicular tissue histopathologic differences (SCOS and MA) has a different pattern of miRNA expression due to the type of germ cells they present in epithelial tissue of the testis.

L’argomento della tesi verte sui tumori testicolari a cellule germinali (TTCG) ed ha come scopi principali la valutazione: i) del ruolo dei riarrangiamenti AZFc del cromosoma Y come fattore di rischio per lo sviluppo di tale patologia; ii) degli effetti del trattamento citotossico sulla ripresa della spermatogenesi e sul genoma/epigenoma spermatico. Il lavoro di tesi fornisce informazioni aggiuntive in merito ai tumori testicolari a cellule germinali (TTCG) con possibili applicazioni nella pratica clinica. La conferma del ruolo della delezione gr/gr nella suscettibilità allo sviluppo di tale patologia, ha permesso di individuare una categoria di pazienti per i quali sarebbe consigliato un follow-up con cadenza periodica. Inoltre, stimola ulteriore ricerca per quanto concerne le duplicazioni parziali AZFc che secondo il nostro lavoro conferiscono un rischio significativo nei soggetti con alterata spermatogenesi. Per tutti coloro che hanno sviluppato TTCG e sono stati trattati, proponiamo l’utilizzo dell’SDF come biomarcatore di danno al DNA spermatico indotto da trattamento citotossico. A tale proposito, è opportuno rivalutare il tempo di attesa oltre il limite temporale di 2 anni che viene attualmente consigliato al paziente oncologico per la ricerca di una gravidanza spontanea. L’introduzione nella pratica clinica di tale biomarcatore permetterebbe, quindi, di monitorare il danno genomico, in modo tale da poter fornire informazioni personalizzate ai pazienti oncologici riguardo la tempistica più appropriata per la ricerca di un concepimento naturale.