| Domain | High-confidence finding | Quantitative/current evidence | Suggested ontology terms |
|---|---|---|---|
| Disease identity and identifiers | Frasier syndrome is a rare Mendelian **WT1 disorder** characterized principally by progressive glomerulopathy, 46,XY gonadal dysgenesis/DSD, and predisposition to gonadoblastoma. Classical syndrome labels increasingly overlap within a broader WT1-disorder spectrum. Identifiers: **OMIM 136680**; **ORPHA:347**; MONDO identifier requires database validation. (pqac-00000001, pqac-00000019) | No population-based prevalence or incidence estimate is established. | Frasier syndrome; WT1 disorder; MONDO ID **verify**; OMIM:136680; ORPHA:347 |
| Causal gene and inheritance | Heterozygous germline variants in **WT1** at 11p13 cause disease; classical Frasier syndrome is usually associated with intron 9 donor splice-region variants. Autosomal-dominant transmission is possible, although many cases are apparently de novo. (pqac-00000022) | A 2023 patient had de novo **NM_024426.6:c.1447+4C>T**, absent in both parents and a sibling. (pqac-00000000, pqac-00000022) | WT1; HGNC gene term **validate**; autosomal dominant inheritance; de novo variant |
| Molecular defect | Classical intron 9 variants disrupt alternative splicing of WT1 transcripts encoding isoforms with or without the Lys-Thr-Ser insertion. They reverse the normal renal **+KTS:−KTS ratio from approximately 2:1 toward 1:2**, impairing WT1-dependent podocyte maintenance and gonadal development. (pqac-00000002, pqac-00000016) | Four of seven splice-site cases in the 2024 Dutch WT1 cohort involved intron 9; all four developed CKD, with median CKD onset at 15 years. (pqac-00000016) | RNA splicing; regulation of transcription; GO terms **validate**; WT1 +KTS and −KTS isoforms |
| Pathogenic variants | Recurrent classical substitutions occur at intron 9 donor-site positions, especially **c.1447+4C>T** and variants at +4/+5. These are germline splice-altering variants; pathogenicity requires transcript-aware ClinVar/ACMG review. (pqac-00000001, pqac-00000022) | Population allele frequencies were not reported in the reviewed studies and are expected to be extremely low; confirm each allele in gnomAD/ClinVar. | Sequence variant; splice donor variant; ClinVar classification **variant-specific validation required** |
| Renal phenotype and onset | Persistent proteinuria typically begins in childhood and progresses to steroid-resistant nephrotic syndrome, FSGS, CKD, and ESKD. Progression is generally slower and later than in classic Denys–Drash syndrome. (pqac-00000001, pqac-00000003) | Historical reports place onset of proteinuria/edema/hypertension around ages 2–10 and mean diagnosis at 16.3 ± 2.3 years. In the broader 2024 WT1 cohort, CKD occurred in 25/43 (58%) and kidney failure in 22/43 (51%); all ten patients with confirmed FSGS developed kidney failure. (pqac-00000002, pqac-00000016, pqac-00000017) | Proteinuria; steroid-resistant nephrotic syndrome; focal segmental glomerulosclerosis; chronic kidney disease; end-stage kidney disease; corresponding HPO IDs **validate** |
| Renal pathology and target cell | The characteristic lesion is usually FSGS, reflecting progressive dysfunction and loss of glomerular podocytes; diffuse mesangial sclerosis can occur but is more characteristic of severe early-onset WT1 disease. (pqac-00000003, pqac-00000018) | In the 2024 cohort, FSGS was confirmed in 11 patients at median age 4 years; DMS occurred in three, all in the first week of life. These figures describe the broader WT1 spectrum, not Frasier syndrome alone. (pqac-00000016) | Podocyte (CL term **validate**); glomerulus; FSGS; DMS; UBERON kidney/glomerulus terms **validate** |
| 46,XY DSD and puberty | Many affected 46,XY individuals have streak/dysgenetic gonads and female external genitalia; others have ambiguous or male genitalia with cryptorchidism or hypospadias. Gonadal failure may cause absent puberty, primary amenorrhea, and hypergonadotropic hypogonadism. (pqac-00000000, pqac-00000020) | A 2023 case first presented at age 15 with delayed puberty and carried c.1447+4C>T. In a broader 333-case WT1 review, 183 (55%) were 46,XY; 219 (66%) had a female phenotype, including 69/219 (32%) with XY sex reversal. (pqac-00000001, pqac-00000008) | 46,XY DSD; complete/partial gonadal dysgenesis; female external genitalia in 46,XY; delayed puberty; primary amenorrhea; hypergonadotropic hypogonadism; HPO IDs **validate** |
| Gonadal tumors | Dysgenetic gonads containing Y-chromosome material confer substantial risk of gonadoblastoma, sometimes with dysgerminoma or other germ-cell/sex-cord tumors; risk begins in childhood and extends through adolescence/adulthood. (pqac-00000003, pqac-00000017) | Three gonadoblastomas occurred among nine patients with sex reversal in a 2014 WT1 cohort. The 2024 cohort reported four gonadoblastomas, including one intron 9 case at age 23, plus intratubular germ-cell neoplasia in another intron 9 case at age 15. (pqac-00000007, pqac-00000017) | Gonadoblastoma; dysgerminoma; gonadal dysgenesis; streak gonad; NCIT tumor terms **validate** |
| Other tumors | Wilms tumor is part of the wider WT1-disorder spectrum but appears less characteristic of classical intron 9 Frasier syndrome than of truncating/deletion or DNA-binding-domain WT1 disorders. (pqac-00000016) | In the 2024 cohort, Wilms tumor occurred in 26/43 overall, but in **0/4 intron 9 splice-variant cases**; ascertainment was phenotype-biased. (pqac-00000016) | Wilms tumor; nephroblastoma; NCIT term **validate** |
| Diagnosis | Diagnosis integrates childhood proteinuria/SRNS or FSGS, genital or pubertal findings, sex-chromosome analysis, and molecular confirmation of a pathogenic germline WT1 variant. Phenotypic females with unexplained SRNS, CKD, delayed puberty, or primary amenorrhea should undergo karyotyping and WT1 testing. (pqac-00000001, pqac-00000011) | Full-gene sequencing with deletion/duplication analysis is preferable to hotspot-only testing because WT1 phenotypes and causal variants extend beyond exons 8–9. The 2024 cohort identified 33 unique variants among 43 patients. (pqac-00000016, pqac-00000019) | Genetic test; chromosome analysis; kidney biopsy; serum creatinine/eGFR; urine protein; diagnostic NCIT/LOINC terms **validate** |
| Treatment and surveillance | No approved molecularly targeted therapy exists. Management includes RAAS blockade for proteinuria/hypertension, avoidance of prolonged ineffective immunosuppression in confirmed genetic disease, CKD care, dialysis/transplantation for ESKD, prophylactic removal of dysgenetic gonads after multidisciplinary counseling, and sex-steroid replacement when clinically indicated. (pqac-00000003, pqac-00000011) | In a nine-child WT1 series, all received transplants at median age 5 years; over median nine-year follow-up, two grafts were lost and no post-transplant malignancy occurred. A 2023 Frasier case underwent bilateral gonadectomy and later required hemodialysis while awaiting transplantation. (pqac-00000000, pqac-00000010) | ACE inhibitor; angiotensin-receptor blocker; gonadectomy; hormone-replacement therapy; hemodialysis; kidney transplantation; NCIT intervention IDs **validate** |
| Prognosis | Untreated nephropathy is chronic and progressive, usually culminating in ESKD; gonadal malignancy is preventable through timely recognition and management. Genetic FSGS has negligible recurrence risk after kidney transplantation compared with non-genetic SRNS. (pqac-00000001, pqac-00000010) | Frasier-specific survival rates and life expectancy are unavailable. Broader WT1 transplant data show useful long-term graft survival, while renal timing varies substantially by variant class. (pqac-00000010, pqac-00000015) | Progressive disease; kidney failure; transplant outcome; quality-of-life terms **validate** |
| Epidemiology and population | The syndrome is ultra-rare, reported across multiple ancestries and geographic regions; no established sex ratio is meaningful because chromosomal sex, gonadal sex, phenotype, and gender may differ. No founder effect, carrier frequency, or population-specific enrichment is established. | WT1 variants accounted for approximately 6% of SRNS in one intensively characterized cohort, but this is not Frasier-syndrome prevalence. (pqac-00000007) | Rare genetic disease; Mendelian disease; prevalence term **not quantified** |
| Models | Reduced +KTS expression in heterozygous mice produces glomerulosclerosis; homozygous loss of +KTS causes complete XY sex reversal, supporting causal renal and gonadal branches of the human mechanism. (pqac-00000003) | Models reproduce core biology but do not capture the full variability, tumor risk, psychosocial outcomes, or long-term human disease course. | Mus musculus (NCBI Taxon:10090); podocyte; gonadal somatic cell; knockout/knock-in model terms **validate** |
| Major evidence gaps | Frasier-specific prospective natural-history, penetrance, prevalence, quality-of-life, fertility, long-term tumor-risk, and treatment-response data are lacking. No validated protective environmental factors, gene–environment interactions, modifiers, disease-specific epigenomic signature, metabolomic/proteomic biomarker, gene therapy, or interventional trial was identified. | Available evidence is dominated by case reports, retrospective WT1-spectrum cohorts, and small systematic compilations; the completed WT1 registry NCT01252901 enrolled 52 participants but was observational. | Natural-history study; patient registry; molecular biomarker; clinical trial terms **validate** |


*Table: Compact synthesis of high-confidence Frasier syndrome genetics, clinical features, mechanisms, management, quantitative evidence, ontology candidates, and major knowledge gaps. Broader WT1-spectrum statistics are explicitly distinguished from Frasier-specific observations.*