Dysplasia Of The Fibrous Sheath Research Articles

Results and perinatal outcomes from 189 ICSI cycles of couples with asthenozoospermic men and flagellar defects assessed by transmission electron microscopy

Research questionDo patients presenting with flagella ultrastructural defects as assessed by electron microscopy, and defined within three phenotypes (dysplasia of the fibrous sheath [DFS], primary flagellar dyskinesia [PFD] and non-specific flagellar abnormalities [NSFA]), have decreased chances of success in intracytoplasmic sperm injection (ICSI) or adverse obstetric and neonatal outcomes? DesignRetrospective analysis of 189 ICSI cycles from 80 men with spermatozoa flagellum ultrastructural defects (DFS [n = 16]; PFD [n = 14]; NSFA [n = 50] compared with a control group (n = 97). Cycles were cumulatively analysed. All fresh and frozen embryo transfers resulting from each ICSI attempt were included. The effect of transmission electron microscopy (TEM) phenotype on the main ICSI outcomes was assessed by a multivariate logistic regression combined with a generalized linear mixed model to account for the non-independence of the observations. ResultsNo predictive value of TEM phenotype was found on the main outcomes of ICSI, namely fertilization rates, pregnancy and delivery rates, and cumulative pregnancy and delivery rates. Cumulative pregnancy rates ranged from 29.0–43.3% in the different TEM phenotype subgroups compared with 36.8% in the control group. Cumulative live birth rates ranged from 24.6–36.7% compared with 31.4% in the control group. No increase was found in miscarriages, preterm births, low birth weights or birth abnormalities. ConclusionsData on the cumulative chances of success in ICSI of patients with ultrastructural flagellar defects, a rare cause of male infertility often associated with an underlying genetic cause, are reassuring, as are obstetrical and neonatal outcomes in this population.

Study of cytoskeleton from microscopic point of view: Our experience

The manuscript deals with our studies and experiences in the assessment of cytoskeleton in different cellular models and situations. The immunofluorescent study of several cytoskeletal proteins was relevant in the evaluation of a therapy for osteoarthritis, in case of alkaptonuria and in testing the efficacy of docetaxel in neuroblastoma cancer cells leading to apoptosis. A relevant part of our experience focus on the study of cytoskeleton in seminiferous epithelium and spermatozoa, identifying alterations affecting blood-testis barrier after a silver nanoparticle treatment, chromosomal segregation in case of varicocele, sperm motility and diagnosing systematic sperm defects as “Primary ciliary dyskinesia” and “Dysplasia of the fibrous sheath”. The evaluation of cytoskeleton represents a specific and sensitive analysis in establishing the health status of different cells.

Sperm with fibrous sheath dysplasia and anomalies in head-neck junction: focus on centriole and centrin 1

Spermatozoa with a rare combination of two monomorphic sperm defects, dysplasia of the fibrous sheath (DFS) and alterations in head-mid-piece junction were analysed. The main focus was to explore the status of the centriole, a key organisation during fertilisation, using the centrin 1, a calcium-binding protein linked to this structure. The sperm quality was examined by light, scanning and transmission electron microscopy (SEM, TEM); immunocytochemistry was performed for tubulin, A-kinase anchor protein 4 (AKAP4) and centrin 1. Spermatozoa showed DFS defect associated with anomalies in head-tail attachment detected by SEM and TEM. Immunolocalisation of tubulin, AKAP4 and centrin 1 confirmed these alterations. Centrin 1 was visible in 67% of spermatozoa (in only 13% centrin localised in a normal position); in the majority of sperm centrin 1's location was altered, sometimes bent; often four spots, indicating the presence of two implantation fossae, were detected. At the centriolar level, immunoreactive fragments, frequently invading the entire short and thick tail, were observed. Centrin 1 is an essential component of the spermatozoa connecting piece and plays a role in centrosome dynamics during sperm morphogenesis and in zygotes and early embryos during spindle assembly. It is important to shed light on these rare conditions in order to better manage the patients during assisted reproductive technology.

Genetically determined and functional human sperm motility decrease

Motility is the most important property of mammalian sperm required for fertilization. Axoneme and axoneme surrounding tail components are the morphological substrate of sperm motility. Quantitative research methods of human spermatozoa motility allowed the definition of the normative parameters for fertile men. Exogenous factors, and, rarely, genetic defects may cause a significant reduction in sperm motility. Axonemal anomalies (absence of external and/or internal dynein arms, central pair of microtubules absence) may be the cause of primary ciliary dyskinesia (PCD). PCD—a severe systemic disease of the reduction of sperm motility—is just one symptom. Dysplasia of the fibrous sheath (DFO) is also genetically determined sperm motility decrease. PCD and the DFO are multigene diseases that are inherited in an autosomal recessive manner. Modern molecular biological research methods are used to identify candidate genes. Assisted reproduction technologies (ART) allow men suffering from PCD and DFO to produce offspring. PCD and DFO symptoms appear in the homozygote. Children born after ART have the probability of being mutation carriers. We do not have complete information about etiological factor of genetically determined spermpathology. So we cannot assess the genetic risk degree. However, the possibility of mutations accumulation, which can be a risk factor for distant offspring, should be considered.

Detection of a mutation in the intron of Sperm-specific glyceraldehyde-3-phosphate dehydrogenase gene in patients with fibrous sheath dysplasia of the sperm flagellum.

The fibrous sheath is a unique cytoskeletal structure surrounding the axoneme and outer dense fibres of the sperm flagellum. Dysplasia of the fibrous sheath (DFS) is a defect of spermatozoa observed in severe asthenozoospermic patients and characterised by morphologically abnormal flagella with distorted fibrous sheaths. Sperm-specific glyceraldehyde-3-phosphate dehydrogenase (GAPDS) is a glycolytic enzyme that is tightly associated with the fibrous sheath of the sperm flagellum. The enzymatic activity of GAPDS was investigated in sperm samples of seven patients with DFS and compared to that of normal spermatozoa (n=10). The difference in GAPDS activity in DFS and normal spermatozoa was statistically significant (0.19±0.11 and 0.75±0.11μmol NADH per min per mg protein respectively). Immunochemical staining revealed irregular distribution of GAPDS in the flagellum of DFS spermatozoa. Other five samples with typical alterations in the fibrous sheath were assayed for mutations within human GAPDS gene. In all five cases, a replacement of guanine by adenine was revealed in the intron region between the sixth and the seventh exons of GAPDS. It is assumed that the deficiency in GAPDS observed in most DFS sperm samples is ascribable to a disorder in the regulation of GAPDS expression caused by the mutation in the intron region of GAPDS gene.

Genetically determined patozoospermia. Literature review and research results

Genetic factors (chromosomal aberrations and point mutations) are the cause of infertility in 10–15 % of men with impaired fertility. Homogeneous structural and functional defects in the sperm or the total terato-, asthenozoospermia – rare cases of genetically determined male infertility, are autosomal recessive diseases. Currently, described 4 types of «syndromic» spermopatology. 1. Primary ciliary dyskinesia (PCD) in men with total asthenozoospermia. Affects axoneme structures (microtubules, dynein arms, radial spokes). It identified more than 20 chromosomal loci responsible for the development of the PCD. 2. Dysplasia of the fibrous sheath of sperm tail in men with asthenozoospermia. The shortened and thickened sperm tail observed with disorganization of vertical columns and cross ribs of the fibrous sheath. Candidate genes – genes family ACAP. 3. Globozoospermia in men with teratozoospermia characterized by the presence of sperm with round heads, primary lack of acrosome and disorganization middle part of the flagellum. Found mutations or deletions of genes SPATA16, PICK1 and DPY19L2. 4. Syndrome decapitated spermatozoa in men with teratozoospermia (microcephaly). Abnormalities in the spermiogenesis development of connecting part jf the tail and proximal (morphologically normal) centrioles. In 2012–2014 years we have studied the ultrastructure of 2267 semen samples of men with impaired fertility. Globozoospermia revealed in 7 patients, dysplasia of the fibrous sheath – 13, decapitated sperm – in one. PCD was revealed in 4 patients (lack of axoneme dynein arms was found in 1 patient, absence of axoneme radial spokes – in 3 patients. The problem of genetically determined patozoospermya must be taken into account when the assisted reproductive technologies practises. There are few cases of successful assisted reproductive technologies with sperm of these patients. We don»t know the etiological factors of syndromic spermopatologe, so we cannot determine the degree of genetic risk.

Morphologically distinct phenotypes of spermatozoa in infertile men reveal down regulation of multiple signaling pathways

Seven morphologically distinct spermatozoal phenotypes can be detected in human semen under electron microscopy: sperm with dysplasia of the fibrous sheath, non-specific flagellar defects, immotile cilia syndrome, acrosomal hypoplasia, defective chromatin condensation and compaction, pin head and sperm without heads. These conditions cannot be identified by routine semen analysis because they are but secondary manifestations of underlying pathology. We hypothesize that proteomics would enable us to better understand the mechanism(s) underlying these pathologies.

Teratozoospermia: spotlight on the main genetic actors in the human

Male infertility affects >20 million men worldwide and represents a major health concern. Although multifactorial, male infertility has a strong genetic basis which has so far not been extensively studied. Recent studies of consanguineous families and of small cohorts of phenotypically homogeneous patients have however allowed the identification of a number of autosomal recessive causes of teratozoospermia. Homozygous mutations of aurora kinase C (AURKC) were first described to be responsible for most cases of macrozoospermia. Other genes defects have later been identified in spermatogenesis associated 16 (SPATA16) and dpy-19-like 2 (DPY19L2) in patients with globozoospermia and more recently in dynein, axonemal, heavy chain 1 (DNAH1) in a heterogeneous group of patients presenting with flagellar abnormalities previously described as dysplasia of the fibrous sheath or short/stump tail syndromes, which we propose to call multiple morphological abnormalities of the flagella (MMAF). A comprehensive review of the scientific literature available in PubMed/Medline was conducted for studies on human genetics, experimental models and physiopathology related to teratozoospermia in particular globozoospermia, large headed spermatozoa and flagellar abnormalities. The search included all articles with an English abstract available online before September 2014. Molecular studies of numerous unrelated patients with globozoospermia and large-headed spermatozoa confirmed that mutations in DPY19L2 and AURKC are mainly responsible for their respective pathological phenotype. In globozoospermia, the deletion of the totality of the DPY19L2 gene represents ∼ 81% of the pathological alleles but point mutations affecting the protein function have also been described. In macrozoospermia only two recurrent mutations were identified in AURKC, accounting for almost all the pathological alleles, raising the possibility of a putative positive selection of heterozygous individuals. The recent identification of DNAH1 mutations in a proportion of patients with MMAF is promising but emphasizes that this phenotype is genetically heterogeneous. Moreover, the identification of mutations in a dynein strengthens the emerging point of view that MMAF may be a phenotypic variation of the classical forms of primary ciliary dyskinesia. Based on data from human and animal models, the MMAF phenotype seems to be favored by defects directly or indirectly affecting the central pair of axonemal microtubules of the sperm flagella. The studies described here provide valuable information regarding the genetic and molecular defects causing infertility, to improve our understanding of the physiopathology of teratozoospermia while giving a detailed characterization of specific features of spermatogenesis. Furthermore, these findings have a significant influence on the diagnostic strategy for teratozoospermic patients allowing the clinician to provide the patient with informed genetic counseling, to adopt the best course of treatment and to develop personalized medicine directly targeting the defective gene products.

Mutation analysis in patients with total sperm immotility.

Perform the genetic characterization of five patients with total sperm immotility using Sanger sequencing and Whole Exome Sequencing (WES), in order to increase the knowledge on the genetics of sperm immotility and, ultimately, allow the identification of potential genetic markers for infertility. Prospective study at a University Medical school. We analysed five men with total sperm immotility, four with dysplasia of the fibrous sheath (DFS), associated with disruption of several axonemal structures, and one patient with situs inversus totalis, which showed absence of dynein arms (DA) and nexin bridges. We screened 7 genes by Sanger sequencing, involved in sperm motility and associated to ultrastructural defects found in these patients (CCDC39, CCDC40, DNAH5, DNAI1, RSPH1, AKAP3 and AKAP4). Additionally, we performed WES analysis in the patient with situs inversus. We identified nine new DNA sequence variants by WES. Two of these variants were considered particularly relevant: a homozygous missense change in CCDC103 gene (c.104G > C, p.R35P) probably related with absence of dynein arms; the other in the INSL6 gene (c.262_263delCC) is thought to be also involved in sperm immotility. Our work suggests that WES is an effective strategy, especially as compared with conventional sequencing, to study highly heterogenic genetic diseases, such as sperm immotility. For future work we expect to expand the analysis of WES to the other four patients and complement findings with expression analysis or functional studies to determine the impact of the novel variants.

Polymorphism of GAPDHS gene in infertle men with dysplasia of sperm tail fibrous sheath

The fibrous sheath (FS) is a unique sperm tail periaxonemal structure, surrounding the axoneme in the principle part of the flagellum. It is known that the motility of sperms is provided mostly by glycolysis (1). Spermspecific glyceraldehyde-3-phosphate dehydrogenase (GAPDHS), one of the enzymes of glycolysis, is tightly associated with FS (2). Oxidation of GAPDHS decreases sperm motility (3). The goal of the present work was to investigate of the gene GAPDHS in sperm samples of the patients with rare form of astenozoospermia - dysplasia of the FS (DFS), presumably of genetic origin.

Meiotic segregation and sperm DNA fragmentation in Tunisian men with dysplasia of the fibrous sheath (DFS) associated with head abnormalities.

Dysplasia of the Fibrous Sheath (DFS) is a primitive flagellar pathology for which a broad spectrum of ultrastructural flagellar abnormalities has been described responsible for a severe to total asthenozoospermia. To this phenotype other morphological abnormalities including cephalic and abnormalities in nuclear structure can be associated that could compromise embryonic development in case of use of Assisted Reproductive Technology (ART). The aim of this study was to evaluate the level of DNA fragmentation and aneuploidy rate in ejaculated spermatozoa of Tunisian men presented with DFS sperm defect associated to high percentage of head abnormalities and to compare the results with those from fertile men. Sperm DNA fragmentation was evaluated by the terminal desoxynucleotidyl transferase mediated deoxyuridine triphosphate biotin nick-end labelling (TUNEL) assay. The study of meiotic segregation was performed by Fluorescence in situ hybridization (FISH) for chromosomes X, Y and 18. The mean DNA fragmentation index was significantly higher in patients compared to the control group. FISH revealed a significantly higher incidence of sperm aneuploidies compared with controls. All patients showed elevated frequencies of sex chromosomes disomy, disomy 18 and diploidy. In some cases of syndromic teratozoospermia due to sperm tail structural abnormalities, such as DFS, other morphological cephalic abnormalities may be associated. In these cases we have demonstrated impaired sperm nuclear quality which will affect the results in ICSI. Hence the interest of a thorough study of the sperm nucleus in these forms of infertility in order to predict the chances of success in ART.

Reproductive outcomes in patients with male infertility because of Klinefelter's syndrome, Kartagener's syndrome, round-head sperm, dysplasia fibrous sheath, and ‘stump’ tail sperm

To describe the reproductive outcomes of a heterogeneous group of male infertility conditions causing severe alterations in the sperm parameters (counts, motility, and morphology) because of chromosomal, genetic, or still unknown causes. Source of sperm, fertilization, pregnancy, live birth, and miscarriage rates of patients with Klinefelter's syndrome, Kartagener's syndrome, round-head sperm, dysplasia of the fibrous sheath (DFS), and stump-tail sperm were reviewed. There are differences in the outcome according to the conditions and the source of sperm (ejaculated versus testicular). Klinefelter's syndrome patients have better reproductive outcomes when sperm is present in the ejaculate. Kartagener's syndrome shows better fertilization when testicular sperm is used; however, pregnancy rates and live births did not differ between ejaculated and testicular sperm. Samples with round-head sperm have a lower fertilization potential, pregnancy and live birth compared with Klinefelter's and Kartagener's syndromes. In men with DFS and stump-tail sperm, the reproductive outcome is poor, with low fertilization and very few babies born. In Klinefelter's and Kartagener's syndrome, the fertilization potential and the live-birth rate are close to that obtained from nonspecific causes of sperm defects. Round-head sperm shows a lower fertility potential, but the addition of assisted oocyte activation and the use of intracytoplasmic morphologically selected sperm injection increased the rates of live birth. Conditions such as DFS and stump tail have a poor prognosis, but the number of cases described in the literature is too limited for drawing final conclusions.

A platform for evaluating sperm RNA biomarkers: dysplasia of the fibrous sheath—testing the concept

To investigate the potential use of correlative microarray-based transcript pairs as candidate markers for male fertility using dysplasia of the fibrous sheath (DFS) as an affected model. It is widely recognized that microarray technology may be limited by cost and that the quality of the transcript remains relatively unknown. To address these issues, we analyzed the stable transcript pairs by qPCR with a systematic primer design process. Experimental study. University. Men with proven fertility and men with a diagnosis of DFS. None. Primer sequences for six genes of interest were designed using Oligo7 and Primer3Plus. Primer specificity was initially assessed in silico by searching the ENSEMBL, University of California Santa Cruz, and National Center for Biotechnology Information databases for nontarget complementary sequences throughout the genome. The ability of transcript pairs to classify samples from males of proven fertility away from DFS was assessed. In conjunction with identifying four new stable transcript pairs, comparison of the DFS qPCR C(t) correlation coefficients revealed the disruption of four stable fertile sample transcript pairs. This suite of transcript pairs resolves DFS. The results show that with effectively designed primers, qPCR may provide an affordable molecular assay to assess male fertility status.

Two cases of sperm immotility: a mosaic of flagellar alterations related to dysplasia of the fibrous sheath and abnormalities of head-neck attachment

To characterize the association of two systematic sperm defects. Case report. University, Interdepartmental Centre for Research and Therapy of Male Infertility. Patient 1, 42 years old, and patient 2, 38 years old, both with severe asthenozoospermia. Family history, physical examination, hormonal analysis, microbial assays, semen analysis, transmission and scanning electron microscopy, immunocytochemistry for tubulin, and fluorescence in situ hybridization (FISH) for chromosomes 18, X, and Y. Admixture of dysplasia of the fibrous sheath (DFS) and head-tail misalignment up to acephalic sperm detected by microscopic methods. In both patients, DFS was present in incomplete form and was associated with acephalic sperm and abnormal head-tail attachment. In patient 2, spermatozoa were also affected by necrosis that may cause fragmentation leading to short flagella; submicroscopic examination allowed defining only the origin of these "stumpy" tails. Immunofluorescence confirmed the sperm alterations. FISH revealed an altered frequency of diploidy and disomy in patient 2 and a slight increase in diploidy in patient 1. The importance of ultrastructural sperm evaluation for correct identification of sperm pathologies is evident, particularly regarding assisted reproduction technology and genetic risk assessment.

The making of abnormal spermatozoa: cellular and molecular mechanisms underlying pathological spermiogenesis

Fertilization in mammals occurs via a series of well-defined events in the secluded environment of the female reproductive tract. The mode of selection of the fertilizing spermatozoon nevertheless remains unknown. As has become evident during in vitro fertilization by sperm microinjection into the oocyte, abnormal spermatozoa can successfully fertilize oocytes. Under these extreme conditions, post-fertilization events, early embryonic development and implantation are significantly compromised indicating that the contribution of spermatozoa extends beyond sperm penetration. Microscopic identification of normal spermatozoa is a well-standardized procedure but insights into the mechanisms that lead to aberrant sperm differentiation and into the subcellular nature of sperm abnormalities have only recently begun to be obtained. The spermatozoon is the result of a complex development in which spermatid organelles give rise to various structural components with characteristic functions. Similar to other differentiated cells, the spermatozoon has a specific pathology that is most clearly identified by ultrastructural evaluation coupled with immunocytochemistry and molecular techniques. This multidisciplinary approach allows the precise characterization of sperm abnormalities, including structural, molecular and functional aspects. We summarize here studies of the physiopathology of spermiogenesis in two abnormal sperm phenotypes of infertile men: dysplasia of the fibrous sheath and acephalic spermatozoa/abnormal head-tail attachment. The characterization of the abnormalities of the tail cytoskeleton and centrioles has uncovered aspects of the subcellular basis of pathological spermiogenesis, has suggested experimental approaches to explore the nature of these anomalies and has opened the way for genetic studies that will ultimately lead to the design of the therapeutic tools of the future.

Fluorescence In Situ Hybridization Studies of Sperm Aneuploidies in Infertile Men

Fluorescence in situ hybridization analysis, performed with chromosome specific DNA probes labeled with fluorochromes, is a simple and reliable tool for the indirect study of aneuploidies in interphase cells such as spermatozoa. It is known that infertile male patients with poor sperm quality, due to different causes, produce cytogenetically abnormal spermatozoa despite a normal constitutional karyotype as a result of an altered intra-testicular environment that negatively affects the mechanisms controlling chromosome segregation during cell division. A particular subgroup of this category is composed of individuals with systematic sperm defects, characterized by an identical, specific alteration that affects the vast majority of their sperm population. Altered meiotic segregation has been described mainly in globozoospermia and in sperm with dysplasia of the fibrous sheath. Moreover, we also considered sperm aneuploidies in the presence of somatic chromosome abnormalities: numerical chromosomal anomalies, such as the presence of an extra chromosome and structural chromosomal anomalies, including translocations and inversions. It is known that somatic chromosomal abnormalities are often associated with infertility and have definite consequences on the cytogenetic anomalies observed in spermatozoa. Since individuals with abnormal semen parameters, also those that are carriers of a constitutional abnormal karyotype, make up the majority of intracytoplasmic sperm injection candidates, it is of great interest to study the chromosomal constitution of their spermatozoa. The problem of the possible presence of aneuploidy in sperm from infertile men should be seriously considered due to the documented risk of the transmission of a chromosomal imbalance to offspring.

Isolated teratozoospermia: a cause of male sterility in the era oF ICSI?

Single structural defects involving the totality of ejaculated sperm are among rare cases of untreatable human male infertility. This form of infertility is of genetic origin and is generally transmitted as an autosomal recessive traits. Acrosome agenesis or globozoospermia results from perturbed expression of nuclear proteins or from an altered Golgi-nuclear recognition during spermiogenesis. Failed fertilization after intracytoplasmic sperm injection (ICSI) of acrosomeless sperm is consistent with an inability of sperm to activate oocytes. Acephalic spermatozoa result from a head-neck defect due to a failure of migration of the tail anlagen and related centriole to the caudal pole of spermatids. An abnormal sperm centrosome function may explain the defective embryo cleavage after ICSI with sperm carrying a fragile head-neck junction. Primary cilia dyskinesia (PCD) and dysplasia of the fibrous sheath (DFS) are isolate defects associated with absent or greatly reduced sperm motility due to an abnormal ciliary structure and function (PCD) or to a disorganized fibrous sheath (DFS). Numerous defective genes are potentially involved in human isolated teratozoospermia but such defects have not been defined at the molecular level in most cases. IVF-ICSI is the only available method for obtaining live births with sperm carrying these defects, but the outcome is poor and the genetic risk for the subsequent generation can not be determined.

P-601: Are ICSI fertilization rates lower in men with profound asthenospermia?

It is thought that most cases of severe asthenospermia are caused by flagellar abnormalities such as immotile cilia syndrome and dysplasia of the fibrous sheath. Based on the potential for these conditions to affect centriolar integrity, we hypothesized that sperm from these patients might deliver substandard fertilization rates with ICSI. In this study of men with severely low ejaculated sperm motility, a population likely enriched in flagellar defects, we compared ICSI fertilization rates to a contemporary cohort of men with higher ejaculated sperm motility.

Fluorescence in situ hybridization and molecular studies in infertile men with dysplasia of the fibrous sheath

To perform fluorescence in situ hybridization (FISH) and molecular analysis in patients with the genetic sperm defect "dysplasia of the fibrous sheath" (DFS). Retrospective study. Regional Referral Center for Male Infertility, Siena, Italy. Twelve infertile patients with DFS sperm defects. Family history, lymphocytic karyotype, physical and hormonal assays, semen analysis. The DFS sperm phenotype was defined by light, fluorescent, and electron microscopy. Sperm chromosomal constitution was examined by FISH. Gene deletions were tested by polymerase chain reaction. The genetic sperm defect DFS was determined by transmission and scanning electron microscopy. Immunofluorescence staining of A-kinase anchoring protein 4 (AKAP4) showed a moderate and diffuse signal, revealing a disorganized and incompletely assembled fibrous sheath. In 11 of 12 DFS patients, polymerase chain reaction for detecting the presence of partial sequence of AKAP4/AKAP3 binding regions gave positive results. Fluorescence in situ hybridization was performed in decondensed sperm nuclei with probes for chromosomes 18, X, and Y. The mean disomy frequency of chromosome 18 was in the normal range, whereas the mean disomy frequencies of sex chromosomes and diploidies were twice those of controls. These results should be considered when DFS sperm are used in assisted reproductive technology, owing to the high risk of transmission of chromosomal unbalance and of DFS sperm defects to male offspring.

Gene deletions in an infertile man with sperm fibrous sheath dysplasia

Asthenozoospermia may sometimes be related to genetic structural defects of the sperm tail detectable by transmission electron microscopy. Dysplasia of the fibrous sheath (DFS) is a genetic sperm defect, characterized by dysplastic development of the axonemal and periaxonemal cytoskeleton. We report the case of an infertile man with normal sperm count and total sperm immotility in which dysplasia of the fibrous sheath, Akap3, Akap4 gene deletions, meiotic segregation of chromosomes 18, X and Y and Y microdeletions were investigated. A 32-year-old man with a 3-year history of primary infertility presented at our Regional Referral Center for Male Infertility. Family medical history, lymphocyte karyotype, PCR analysis, physical examination, hormone assays and semen analysis were performed. Ultrastructural sperm evaluation showed dysplasia of the fibrous sheath. Immunostaining of AKAP4 protein was negative in sperm tails. PCR analysis revealed intragenic deletions of the Akap3 and Akap4 genes. Fluorescence in situ hybridization on sperm showed a high frequency of XY disomy. In this infertile patient, our results suggest a possible relationship between dysplasia of the fibrous sheath, partial deletions in the Akap3 and Akap4 genes and absence of AKAP4 protein in the fibrous sheath. These findings, however, were not detected in another four patients with dysplasia of the fibrous sheath. Our results require future confirmatory molecular analyses.