Multiple morphological abnormalities of the flagella (MMAF) represent a severe form of sperm defects leading to asthenozoospermia and male infertility. In this study, we identified a novel homozygous splicing mutation (c.871-4 ACA>A) in the adenylate kinase 7 (AK7) gene by whole-exome sequencing in infertile individuals. Spermatozoa from affected individuals exhibited typical MMAF characteristics, including coiled, bent, short, absent, and irregular flagella. Transmission electron microscopy analysis showed disorganized axonemal structure and abnormal mitochondrial sheets in sperm flagella. Immunofluorescence staining confirmed the absence of AK7 protein from the patients' spermatozoa, validating the pathogenic nature of the mutation. This study provides direct evidence linking the AK7 gene to MMAF-associated asthenozoospermia in humans, expanding the mutational spectrum of AK7 and enhancing our understanding of the genetic basis of male infertility.
Humans ; Male ; Sperm Tail/ultrastructure* ; Homozygote ; Consanguinity ; Asthenozoospermia/pathology* ; Infertility, Male/genetics* ; Mutation ; Pakistan ; Adenylate Kinase/genetics* ; Adult ; Pedigree ; RNA Splicing ; Exome Sequencing ; Spermatozoa

Male infertility can result from impaired sperm motility caused by multiple morphological abnormalities of the flagella (MMAF). Distinct projections encircling the central microtubules of the spermatozoal axoneme play pivotal roles in flagellar bending and spermatozoal movement. Mammalian sperm-associated antigen 17 ( SPAG17 ) encodes a conserved axonemal protein of cilia and flagella, forming part of the C1a projection of the central apparatus, with functions related to ciliary/flagellar motility, skeletal growth, and male fertility. This study investigated two novel homozygous SPAG17 mutations (M1: NM_206996.2, c.829+1G>T, p.Asp212_Glu276del; and M2: c.2120del, p.Leu707*) identified in four infertile patients from two consanguineous Pakistani families. These patients displayed the MMAF phenotype confirmed by Papanicolaou staining and scanning electron microscopy assays of spermatozoa. Quantitative real-time polymerase chain reaction (PCR) of patients' spermatozoa also revealed a significant decrease in SPAG17 mRNA expression, and immunofluorescence staining showed the absence of SPAG17 protein signals along the flagella. However, no apparent ciliary-related symptoms or skeletal malformations were observed in the chest X-rays of any of the patients. Transmission electron microscopy of axoneme cross-sections from the patients showed incomplete C1a projection and a higher frequency of missing microtubule doublets 1 and 9 compared with those from fertile controls. Immunofluorescence staining and Western blot analyses of spermatogenesis-associated protein 17 (SPATA17), a component of the C1a projection, and sperm-associated antigen 6 (SPAG6), a marker of the spring layer, revealed disrupted expression of both proteins in the patients' spermatozoa. Altogether, these findings demonstrated that SPAG17 maintains the integrity of spermatozoal flagellar axoneme, expanding the phenotypic spectrum of SPAG17 mutations in humans.
Humans ; Male ; Infertility, Male/pathology* ; Sperm Tail/ultrastructure* ; Homozygote ; Microtubule-Associated Proteins/genetics* ; Axoneme/genetics* ; Spermatozoa/ultrastructure* ; Adult ; Mutation ; Sperm Motility/genetics* ; Pedigree ; Microtubules ; Microtubule Proteins/genetics*

The syndrome of multiple morphological abnormalities of the sperm flagella (MMAF) is one of the most serious kinds of sperm defects, leading to asthenoteratozoospermia and male infertility. In this study, we use whole-exome sequencing to identify genetic factors that account for male infertility in a patient born from a consanguineous Pakistani couple. A homozygous frameshift mutation (c.1399_1402del; p.Gln468ArgfsTer2) in axonemal dynein light chain domain containing 1 ( AXDND1 ) was identified in the patient. Sanger sequencing data showed that the mutation was cosegregated recessively with male infertility in this family. Papanicolaou staining and scanning electron microscopy analysis of the sperm revealed severely abnormal flagellar morphology in the patient. Immunofluorescence and western blot showed undetectable AXDND1 expression in the sperm of the patient. Transmission electron microscopy analysis showed disorganized sperm axonemal structure in the patient, particularly missing the central pair of microtubules. Immunofluorescence staining showed the absence of sperm-associated antigen 6 (SPAG6) and dynein axonemal light intermediate chain 1 (DNALI1) signals in the sperm flagella of the patient. These findings indicate that AXDND1 is essential for the organization of flagellar axoneme and provide direct evidence that AXDND1 is a MMAF gene in humans, thus expanding the phenotypic spectrum of AXDND1 frameshift mutations.
Humans ; Male ; Sperm Tail/ultrastructure* ; Frameshift Mutation ; Infertility, Male/pathology* ; Pakistan ; Pedigree ; Consanguinity ; Axonemal Dyneins/genetics* ; Adult ; Spermatozoa ; Exome Sequencing

OBJECTIVETo observe the ultrastructural changes of sperm flagella in patients with severe idiopathic asthenospermia.

METHODSUsing the transmission electron microscope, we examined the ultrastructure of sperm flagella from 22 patients with severe idiopathic asthenospermia.

RESULTSUltrastructural anomalies were found in all the 22 patients, 6 with partial or complete absence of internal and external dynamic arms in dedicative of primary ciliary dyskinesia, 1 with hyperplasia, hypertrophy and disordered organization of the fibrous sheath usually referred to as dysplasia of the fibrous sheath, and the other 15 with non-specific flagellar anomalies.

CONCLUSIONExamination of the ultrastructure of sperm flagella in severe idiopathic asthenospermia patients can help to distinguish congenital from acquired flagellar structural anomalies and give valuable guidance in the treatment.

Adult ; Asthenozoospermia ; pathology ; Humans ; Male ; Sperm Tail ; ultrastructure

The ultrastructural abnormalities of human sperm flagella can cause sperm movement disorders. Dysplasia of the fibrous sheath (DFS) is an autosomal recessive genetic disease. The affected sperm in 95-100% of the patients display short, thick and irregular tails. Transmission electron microscopy can be used to confirm the diagnosis, which reveals gross abnormal flagella, with hypertrophy and hyperplasia of the fibrous sheath, without orderly disposition in longitudinal columns and transversal ribs. The axoneme shows variable distortion or almost complete obliteration. Microtubular doublets may exhibit partial or total lack of dynein arms. The genetic etiology of DFS is not yet clear. DFS does not affect the rates of fertilization and clinical pregnancy in ICSI, but due attention should be paid to the genetic risks in the offspring of the patient.
Humans ; Hyperplasia ; complications ; pathology ; Hypertrophy ; complications ; pathology ; Infertility, Male ; Male ; Microscopy, Electron ; Sperm Motility ; physiology ; Sperm Tail ; pathology ; ultrastructure ; Spermatozoa

AIMTo investigate the changes of the spermatozoa ultrastructures before and after renal transplantation in uremic patients.

METHODSThe sperm of five uremic patients before and after transplantation and four healthy volunteers were collected and examined by scanning electron microscopy.

RESULTSAbnormal spermatozoa were found in patients pre-transplantation; abnormalities included deletion of the acrosome, absence of the postacrosomal and postnuclear ring, dumbbell-like changes of the head, tail curling, and absence of the mitochondrial sheath in the mid-segment. After renal transplantation, most of the spermatozoa became normal.

CONCLUSIONThere are many abnormalities with regard to the appearance and structure of the head, acrosome, mitochondria and tail of the spermatozoa in uremic patients. The majority of the spermatozoa returned to normal after renal transplantation, but a few still presented some abnormalities possibly relating to the administration of immunosuppressants.

Acrosome ; pathology ; Adult ; Case-Control Studies ; Humans ; Kidney Failure, Chronic ; complications ; Kidney Transplantation ; Male ; Microscopy, Electron ; Renal Dialysis ; Sperm Head ; pathology ; Sperm Tail ; pathology ; Spermatozoa ; pathology ; ultrastructure