Spermatogenic Failure, X-linked, 3 (SPGFX3; CFAP47-related MMAF): Research Report

Scope and verification. I verified the core facts below by search or fetch in this session. These are the OMIM, MONDO and DOID identifiers, the gene assignment, and the contents of two primary papers (Liu C 2021, PMID 33472045; Liu M 2023, DOI 10.3389/fendo.2023.1155639).

• Only those two primary papers were read. Other CFAP47 reports exist in the literature, and I did not retrieve them.
• Ontology IDs marked (unverified) are from memory. Look them up before binding them; do not copy them into a KB entry as written.
• I did not obtain a PMID for the 2023 Frontiers paper.
• OMIM, Orphanet, ClinVar, gnomAD and GeneReviews pages were not read directly. Claims attributed to them come from search snippets or from the primary papers' own text.
• The fetch-reference cache and just validate-* were not run, so none of the snippets below has been checked against references_cache/.

1. Disease Information

Overview. SPGFX3 is an X-linked recessive cause of male infertility. It is characterized by asthenoteratozoospermia with multiple morphological abnormalities of the sperm flagella (MMAF): flagella that are absent, short, coiled, bent or of irregular caliber. It is caused by hemizygous loss-of-function or missense variants in CFAP47 at Xp21.1. Affected men are otherwise described as having isolated infertility. Neither paper reports a syndromic extra-reproductive phenotype.

Identifiers.

• Synonyms: SPGFX3; X-linked spermatogenic failure 3.
• Parent concept (Mondo): spermatogenic failure, within male infertility.
• OMIM cross-reference: SPGF1 (258150) for genetic heterogeneity of spermatogenic failure.
• Naming discrepancy: the LOVD entry uses the obsolete symbol CXorf59, which is the old name of CFAP47.
• Source level: the evidence is from individual patients (exome sequencing, semen analysis, sperm electron microscopy). OMIM and MONDO are aggregated disease-level resources built on those reports.
• Near-namesake caution: an unofficial dismech-hosted report on SPGFX1/TEX11 exists. Search-result commentary flagged its SPGFX gene mappings as internally inconsistent. Do not take SPGFX2 or SPGFX4 assignments from it. Confirm each against OMIM.

2. Etiology

• Causal factor: genetic. Hemizygous CFAP47 variants in males. Reported alleles are missense changes and one whole-gene deletion.
• Genetic risk factors: no modifier genes or susceptibility loci have been described in the papers I read.
• Environmental risk factors, protective factors, gene-environment interactions: none reported. I would not infer any.
• Allele caution: p.V472M (c.1414G>A) is reported at about 0.009 allele frequency in East Asian reference populations, per Liu M 2023. That is high for a fully penetrant X-linked recessive allele, so its pathogenicity rests on functional data, not rarity.

3. Phenotypes

All phenotypes are laboratory or sperm-morphology findings in adult males (human clinical evidence). Frequencies are the cohort counts in the primary papers. Four men were reported in 2021 and two in 2023, so no population-level frequency exists.

2021 morphology by subject (Liu C 2021, Table 2, as summarized by the fetch):

• T115: absent 37.5%, short 34%, coiled 18.5%.
• T176: absent 11%, short 17%, coiled 42%.
• H025: absent 22%, short 14%, coiled 50.5%.

Onset, progression, quality of life. Not reported. Presentation is in adulthood, as couple infertility. Nothing is known about progression or quality of life. Semen findings are presumably stable, but that is an inference.

Hormones and testis. The 2021 paper reports no FSH, LH, testosterone or testicular histology data. I would leave endocrine phenotypes uncurated.

4. Genetic/Molecular Information

• Gene: CFAP47 (cilia- and flagella-associated protein 47). A very large X-linked gene highly expressed in testis.
• Variants reported:

• Screening yield (2021): 243 men with MMAF (CITIC-Xiangya, Changsha) and 88 (Anhui Medical University), plus 24 Australian men with asthenoteratozoospermia. These yielded three missense carriers and the one deletion. The fetch did not give the exact per-cohort breakdown.
• Origin: germline, hemizygous in males.
• Functional consequence: CFAP47 protein is strongly reduced in patient sperm. Loss of function, or reduced function from missense variants, is the working model. I would not claim dominant negative or gain of function.
• Modifier genes, epigenetics, chromosomal abnormalities: none described, apart from the Xp21.1 deletion.
• ClinGen / validity: a search snippet showed a disease database linking CFAP47 to this MONDO term at only "limited" evidence. I did not find a ClinGen CGGV: record. If you record gene-disease validity, copy it from a source record. Do not assign it.

5. Environmental Information

None reported. No toxins, lifestyle factors or infectious agents are implicated.

6. Mechanism / Pathophysiology

Causal chain.

1. A hemizygous CFAP47 variant (missense or deletion) arises in a male. Males have no second X allele to compensate (demonstrated genetically).
2. This leads to markedly reduced CFAP47 protein in sperm. Immunofluorescence shows the signal almost absent at the flagellar base (demonstrated for the 2021 men; Western blot reduction in the 2023 patients).
3. This is associated with reduced or mislocalized partner proteins. CFAP65 is mislocalized in mutant sperm and co-immunoprecipitates with CFAP47. CFAP69, SEPTIN4 and CFAP65 are reduced in the 2023 patients. These expression and localization changes are correlative. Whether CFAP47 regulates them, or is only co-lost with them, is inferred, not demonstrated.
4. This leads to defective axonemal and peri-axonemal assembly. TEM shows disorganized outer dense fibers and missing peripheral doublets or central pair. SPAG16 is reduced. The 2023 patients also show a defective annulus and a disorganized mitochondrial sheath.
5. This results in absent, short, coiled or bent flagella and impaired motility (MMAF, asthenoteratozoospermia).
6. This results in male infertility. Branch (2023 patients): abnormal head morphology and small or absent acrosomes. How a flagellar protein loss produces head defects is not explained and is not established.

Mouse timing. In the Cfap47 mutant mouse, flagellar bending was first seen in the corpus epididymis, not the testis. That suggests a late structural defect, but this is one study.

Cell types and processes.

• Cell types: spermatid and spermatozoon, with Sertoli-cell context.
• Suggested terms (unverified): spermatozoon (CL), spermatid (CL); GO terms for sperm flagellum assembly and axoneme assembly.

Omics, single-cell, CRISPR screens, immune or metabolic involvement. Not reported.

7. Anatomical Structures Affected

• Organs: testis and the male reproductive tract (UBERON testis, epididymis (unverified)).
• Cells: developing and mature sperm.
• Subcellular: sperm flagellum, axoneme, outer dense fibers, fibrous sheath, annulus, mitochondrial sheath, flagellar base (GO cellular component terms to be looked up).
• Lateralization: not applicable.

8. Temporal Development

• Onset: presumably congenital. It is clinically ascertained in adulthood by infertility.
• Course: lifelong. Spontaneous remission is not reported.
• Critical period: none identified.

9. Inheritance and Population

• Inheritance: X-linked recessive (HPO "X-linked recessive inheritance" (verify ID)). Males are affected, with hemizygous variants.
• Carrier females: no phenotype is reported in the sources I read.
• Penetrance and expressivity: semen parameters vary (concentration 0.5–29.5 ×10⁶/mL), but all reported men are infertile. I would not state a formal penetrance.
• Prevalence: not documented. This is a very rare, recently described condition. Do not assign a prevalence class beyond "not yet documented" without a source.
• Populations: reported cases are mostly Chinese, plus one Australian man. Founder effects, anticipation and mosaicism are not described.
• Sex ratio: affects males only.

10. Diagnostics

• Semen analysis shows asthenozoospermia or oligoasthenoteratozoospermia, with a high proportion of absent, short, coiled or irregular-caliber flagella.
• Sperm TEM: disorganized axoneme and outer dense fibers.
• Immunofluorescence of sperm for CFAP47 (and CFAP65, SPAG16) is a research tool, not a clinical test.
• Genetic testing: exome sequencing or an MMAF gene panel including CFAP47. Use chromosomal microarray or CNV analysis for deletions, because the whole-gene deletion was found that way.
• Differential diagnosis: other MMAF genes (for example DNAH1, CFAP43, CFAP44, CFAP69) and primary ciliary dyskinesia. I did not retrieve sources for these; confirm in the literature before curating.
• Screening: none established.

11. Outcome/Prognosis

No mortality or morbidity beyond infertility is reported. Reproductive prognosis with assisted reproduction (ICSI) appears favorable in the 2021 cohort and was mixed in the 2023 patients (see Treatment).

12. Treatment

No curative therapy exists. Sperm from these men is usable for ICSI.

NCIT terms to use, from your CLAUDE.md list:

• Assisted reproduction: bind the closest action term, or leave term: empty. NCIT:C15329 (Surgical Procedure) is not right for ICSI. Search NCIT for ICSI directly.
• Genetic counseling: NCIT:C15240.

ICSI outcomes, Liu C 2021 (Table 3):

Three of four couples achieved clinical pregnancy.

ICSI outcomes, Liu M 2023: no pregnancies in the cycles reported.

• Patient A: 3/5 fertilized, one 8-cell embryo transferred, no pregnancy.
• Patient B: first cycle 1/4 fertilized, second cycle 2/3 fertilized, embryos failed to develop.
• The authors attribute the failures possibly to female factors.

Reconciliation. Pooling both papers, ICSI achieved fertilization in most cycles but pregnancy in three of six couples. The small numbers and female-factor confounders mean this is not a success rate.

Experimental treatments: no NCT trials identified. I did not search ClinicalTrials.gov.

13. Prevention

• Genetic counseling: a carrier mother passes the variant to half of her sons. Daughters of an affected man are obligate carriers. This is standard X-linked reasoning, not drawn from the papers.
• Prenatal and preimplantation testing: possible once the family variant is known. Not discussed in the sources I read.
• Primary prevention: none.

14. Other Species / Natural Disease

I did not search OMIA, so I cannot confirm a naturally occurring animal disease. Treat this section as not assessed.

15. Model Organisms

Mouse (Liu C 2021). A Cfap47 frameshift allele, c.2559insT (p.Gly855Profs*8), made hemizygous in males.

• Fertility: males were sterile over 3 months of breeding.
• Sperm: reduced total and progressive motility, abnormal "folding" movement, lower VCL, VSL and VAP. Sperm concentration was not significantly different.
• Morphology: bent flagella, first seen in the corpus epididymis, and unevenly distributed fibrous sheaths on TEM.
• IVF: lower two-cell and blastocyst rates. ICSI: rates comparable to wild type.
• Localization: Cfap47 signal is mainly in the midpiece in mouse sperm. In human control sperm it is at the flagellar base, which is a species difference.
• Fidelity: the mouse recapitulates infertility, asthenozoospermia and flagellar abnormalities. It differs from humans in having normal sperm concentration and, apparently, a milder morphology (bent flagella versus the human absent, short and coiled mix).
• Suggested links: modeled_mechanisms with PARTIALLY_RECAPITULATES against a flagellar-assembly node; evidence_source: MODEL_ORGANISM.
• Resources: IMPC and MGI entries exist (the search surfaced an MGI:3605549 phenotype page). I did not check them.

Evidence and snippet candidates

Quotes below come from the fetch's paraphrase and summaries, not from verified abstract text. Re-copy exact snippets from references_cache after just fetch-reference PMID:33472045.

Gaps and recommendations

1. Look up the PMID for Liu M 2023 and read any other CFAP47 papers (cohort studies, follow-ups) before finalizing prevalence, yield and variant spectrum.
2. Check OMIM 301059, GeneReviews and Orphanet directly.
3. Search NCIT for an ICSI term. Do not guess a CURIE.
4. Verify every HPO, GO, CL and UBERON term listed above with runoak or the term caches.
5. Check ClinGen for a CFAP47 validity record before filling gene_disease_validity.

Sources: - LOVD SPGFX3 disease #06940 - MalaCards SPGFX3 - Disease Ontology DOID:0112274 - MedGen C5542347 - MONDO:0025354 record - Liu C et al., Am J Hum Genet 2021 (PMC7895902) - Liu M et al., Front Endocrinol 2023 - The X chromosome and male infertility (PMC7864851)

Reference Validation

Checked with linkml-reference-validator 0.3.0.

All extracted references resolved successfully.

Term Validation

Checked with linkml-term-validator 0.4.5, through the ols: adapter.

Terms the report names something else

These identifiers resolve, so nothing about them looks wrong, and the ontology calls them something unrelated to what the report calls them. That usually means the identifier is not the one the sentence needs:

• MONDO:0025354 (5 mentions) - the report calls it "MONDO"; MONDO calls it spermatogenic failure, X-linked, 3
• DOID:0112274 (5 mentions) - the report calls it "DOID"; DOID calls it X-linked spermatogenic failure 3

Prefixes with no resolver

Terms carrying these prefixes were not checked either way, because no configured ontology covers them. An unrecognised prefix may name an ontology this run could not reach as easily as one that does not exist, so nothing here is evidence of fabrication: MGI.