ArticleJournal of assisted reproduction and genetics2026
Biallelic FSIP2 variants are associated with sperm defective chromatin condensation beyond MMAF and acrosomal abnormalities.
Article in Journal of assisted reproduction and genetics, 2026. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Not yet cited in PubMed.
What it found
Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.
The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.
The trial behind it
Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.
Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.
Who cites it
0 citing papers in PubMed.
No citing paper in PubMed yet.
Corrections and comments
PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.
Authors and funding
12 authors.
Funding
No grant is acknowledged in the PubMed record.
Abstract
purposeBiallelic variants in FSIP2 have been associated with multiple morphological abnormalities of the sperm flagella (MMAF) and acrosomal defects. This study aimed to characterize the genetic, sperm phenotypic, and reproductive features of infertile men carrying homozygous FSIP2 variants, with particular attention to sperm nuclear ultrastructure and chromatin condensation.
methodsTwo infertile men with severe sperm morphological abnormalities were enrolled. Whole-exome sequencing and Sanger sequencing were performed to identify candidate variants. Sperm morphology, FSIP2 expression, acrosomal status, nuclear ultrastructure, and chromatin condensation were evaluated using routine semen analysis, immunofluorescence staining, transmission electron microscopy, and chromomycin A3 (CMA3) staining. Intracytoplasmic sperm injection outcomes were reviewed.
resultsTwo homozygous FSIP2 variants were identified in two men with primary infertility, including a frameshift variant, NM_173651.3: c.2519delA, p.(Asn840Metfs*43), and a missense variant, NM_173651.3: c.17798C > T, p.(Ser5933Phe). The missense variant, previously reported in a compound heterozygous context, was identified here in a homozygous state. Spermatozoa from both patients exhibited typical MMAF phenotypes and markedly reduced or absent FSIP2 signals. Acrosomal loss or abnormal acrosomal localization was also observed. Notably, spermatozoa from both patients showed prominent intranuclear vacuoles and increased CMA3 staining, suggesting defective chromatin condensation. After ICSI, both couples achieved fertilization, and one couple achieved a live birth.
conclusionsThese findings suggest an expansion of the genotypic and phenotypic spectrum of FSIP2-associated male infertility. In the two cases studied, biallelic FSIP2 variants were associated with classical MMAF and acrosomal abnormalities, as well as with abnormal nuclear ultrastructure and increased CMA3 staining indicative of impaired chromatin condensation. However, further studies are needed to establish whether these nuclear features represent a direct consequence of FSIP2 deficiency.
Indexed as
Identifiers
42667560What OpenQuestion holds
Registered trials
Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.