Frasier syndrome is a constitutional WT1 disorder caused by heterozygous point variants at the intron 9 donor splice site. The variant allele cannot use the alternative donor that inserts the three amino acids lysine, threonine and serine between the third and fourth zinc fingers, so it produces only the -KTS isoform and the normal excess of +KTS over -KTS is lost. No abnormal protein is made, which separates the mechanism from the dominant negative zinc finger missense variants of Denys-Drash syndrome. The classic presentation is a 46,XY individual with normal female external genitalia and streak gonads, childhood proteinuria progressing through focal segmental glomerulosclerosis to end stage kidney disease in adolescence or early adulthood, and a high risk of gonadoblastoma. Wilms tumor is characteristically absent, in contrast to the rest of the WT1 spectrum. A nosological caveat belongs at the top of this entry. The GeneReviews WT1 Disorder chapter has retired Denys-Drash and Frasier syndrome as clinical designations and describes one phenotypic continuum instead. This entry is curated because MONDO carries the term, the historical literature is indexed under it, and the intron 9 splice mechanism it names is genuinely distinct from the dominant negative zinc finger missense mechanism at the other pole. It should be read as one pole of the WT1 continuum rather than as a separate disease.
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Conditions with similar clinical presentations that must be differentiated from Frasier Syndrome:
name: Frasier Syndrome
creation_date: "2026-09-03T00:00:00Z"
category: Mendelian
categories:
- Disorder of Sex Development
- Glomerular Disease
- Cancer Predisposition Syndrome
parents:
- 46,XY disorder of sex development
disease_term:
preferred_term: Frasier syndrome
term:
id: MONDO:0007635
label: Frasier syndrome
synonyms:
- FS
- Frasier syndrome, autosomal dominant, somatic mutation
description: >-
Frasier syndrome is a constitutional WT1 disorder caused by heterozygous point
variants at the intron 9 donor splice site. The variant allele cannot use the
alternative donor that inserts the three amino acids lysine, threonine and
serine between the third and fourth zinc fingers, so it produces only the -KTS
isoform and the normal excess of +KTS over -KTS is lost. No abnormal protein is
made, which separates the mechanism from the dominant negative zinc finger
missense variants of Denys-Drash syndrome.
The classic presentation is a 46,XY individual with normal female external
genitalia and streak gonads, childhood proteinuria progressing through focal
segmental glomerulosclerosis to end stage kidney disease in adolescence or
early adulthood, and a high risk of gonadoblastoma. Wilms tumor is
characteristically absent, in contrast to the rest of the WT1 spectrum.
A nosological caveat belongs at the top of this entry. The GeneReviews WT1
Disorder chapter has retired Denys-Drash and Frasier syndrome as clinical
designations and describes one phenotypic continuum instead. This entry is
curated because MONDO carries the term, the historical literature is indexed
under it, and the intron 9 splice mechanism it names is genuinely distinct from
the dominant negative zinc finger missense mechanism at the other pole. It
should be read as one pole of the WT1 continuum rather than as a separate
disease.
has_subtypes:
- name: Type 1
display_name: Frasier syndrome type 1 (46,XY, female external genitalia)
description: >-
The classic and much the commonest form, 72 of 88 reviewed cases. Presents
around age 16, usually with primary amenorrhea, and carries the highest
gonadal tumor risk of the three groups at 67%.
evidence:
- reference: PMID:25623218
reference_title: "Gonadal tumor in Frasier syndrome: a review and classification."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "Type 1 Frasier syndrome is characterized by female external genitalia with 46,XY (n = 72); type 2 by male external genitalia with 46,XY (n = 8); and type 3 by female external genitalia with 46,XX (n = 8)."
explanation: Defines the three-way partition by external genitalia and karyotype.
- reference: PMID:25623218
reference_title: "Gonadal tumor in Frasier syndrome: a review and classification."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "The prevalence of gonadal tumor is high in type 1 (67%) and also found in 3 of the 8 type 2 cases, but not in any type 3 cases, which emphasize that preventive gonadectomy is unnecessary in type 3."
explanation: Gives the per-subtype gonadal tumor rates that drive the gonadectomy indication.
- name: Type 2
display_name: Frasier syndrome type 2 (46,XY, male external genitalia)
description: >-
46,XY individuals with male external genitalia, 8 of 88 reviewed cases.
Gonadal tumors occurred in 3 of the 8, so the prophylactic gonadectomy
indication extends to this group. Because secondary sex characteristics
develop normally, the diagnosis is easily missed.
evidence:
- reference: PMID:25623218
reference_title: "Gonadal tumor in Frasier syndrome: a review and classification."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "The prevalence of gonadal tumor is high in type 1 (67%) and also found in 3 of the 8 type 2 cases, but not in any type 3 cases, which emphasize that preventive gonadectomy is unnecessary in type 3."
explanation: Establishes that tumor risk, and so the gonadectomy indication, extends to type 2.
- name: Type 3
display_name: Frasier syndrome type 3 (46,XX, female external genitalia)
description: >-
46,XX individuals with female external genitalia, 8 of 88 reviewed cases.
No gonadal tumor was observed in this group, which is why prophylactic
gonadectomy is not indicated here. The renal disease is unchanged.
evidence:
- reference: PMID:25623218
reference_title: "Gonadal tumor in Frasier syndrome: a review and classification."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "The prevalence of gonadal tumor is high in type 1 (67%) and also found in 3 of the 8 type 2 cases, but not in any type 3 cases, which emphasize that preventive gonadectomy is unnecessary in type 3."
explanation: >-
The absence of tumors in the 46,XX group is the basis for withholding
prophylactic gonadectomy in type 3.
inheritance:
- name: Autosomal dominant, usually de novo
inheritance_term:
preferred_term: Autosomal dominant inheritance
term:
id: HP:0000006
label: Autosomal dominant inheritance
description: >-
Heterozygous intron 9 splice donor variants act dominantly. Most probands
carry a de novo variant.
evidence:
- reference: PMID:32352694
reference_title: "WT1 Disorder."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "WT1 disorder is inherited in an autosomal dominant manner."
explanation: GeneReviews states the mode of inheritance for the WT1 disorder spectrum, of which Frasier syndrome is one pole.
- reference: PMID:32352694
reference_title: "WT1 Disorder."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "Most individuals diagnosed with WT1 disorder have the disorder as the result of an apparent de novo WT1 pathogenic variant"
explanation: Supports the predominantly de novo origin.
pathophysiology:
- name: WT1 Intron 9 Donor Splice Site Variants
biological_scale: MOLECULAR
description: >-
Heterozygous point variants in the intron 9 donor splice site, preferentially
affecting a CpG dinucleotide, disrupt the alternative splice donor that adds
the KTS tripeptide between zinc fingers three and four. The recurrent allele
is NM_024426.6:c.1447+4C>T.
biological_processes:
- preferred_term: mRNA splicing, via spliceosome
term:
id: GO:0000398
label: mRNA splicing, via spliceosome
modifier: ABNORMAL
downstream:
- target: Loss of the +KTS Isoform from the Mutant Allele
causal_link_type: DIRECT
evidence:
- reference: PMID:9499425
reference_title: "Frasier syndrome is caused by defective alternative splicing of WT1 leading to an altered ratio of WT1 +/-KTS splice isoforms."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "Disruption of alternative splicing at the exon 9 splice donor site prevents synthesis of the usually more abundant WT1 +KTS isoform from the mutant allele."
explanation: States that the splice disruption is what prevents +KTS synthesis, which is the edge itself.
evidence:
- reference: PMID:9398852
reference_title: "Donor splice-site mutations in WT1 are responsible for Frasier syndrome."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "Here we demonstrate that FS is caused by mutations in the donor splice site in intron 9 of WT1, with the predicted loss of the +KTS isoform."
explanation: Establishes the causal lesion.
- reference: PMID:9398852
reference_title: "Donor splice-site mutations in WT1 are responsible for Frasier syndrome."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "an alternative splice site in intron 9 allows the addition of three amino acids (KTS) between the third and fourth zinc fingers of WT1"
explanation: Describes the normal splicing event the variant disrupts.
- name: Loss of the +KTS Isoform from the Mutant Allele
biological_scale: MOLECULAR
description: >-
The mutant allele produces only -KTS transcript. Because no altered protein is
translated, the lesion is a quantitative isoform imbalance rather than
dominant negative interference.
biological_processes:
- preferred_term: mRNA splicing, via spliceosome
term:
id: GO:0000398
label: mRNA splicing, via spliceosome
modifier: ABNORMAL
downstream:
- target: WT1 +KTS to -KTS Isoform Imbalance
causal_link_type: DIRECT
evidence:
- reference: PMID:9499425
reference_title: "Frasier syndrome is caused by defective alternative splicing of WT1 leading to an altered ratio of WT1 +/-KTS splice isoforms."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "Disruption of alternative splicing at the exon 9 splice donor site prevents synthesis of the usually more abundant WT1 +KTS isoform from the mutant allele."
explanation: >-
States the edge itself: the splice lesion removes +KTS output from the
mutant allele, which is what leaves the remaining pool imbalanced.
- reference: PMID:9398852
reference_title: "Donor splice-site mutations in WT1 are responsible for Frasier syndrome."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "Examination of WT1 transcripts indeed showed a diminution of the +KTS/-KTS isoform ratio in patients with FS."
explanation: >-
Confirms in patient transcripts that the allele-level loss actually
shifts the measured isoform ratio, rather than being only predicted.
evidence:
- reference: PMID:9499425
reference_title: "Frasier syndrome is caused by defective alternative splicing of WT1 leading to an altered ratio of WT1 +/-KTS splice isoforms."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "In contrast to Denys-Drash syndrome, no mutant protein is produced."
explanation: Distinguishes this mechanism from the dominant negative lesion of Denys-Drash syndrome.
- name: WT1 +KTS to -KTS Isoform Imbalance
biological_scale: MOLECULAR
description: >-
The physiological excess of +KTS over -KTS is reduced. In the kidney the
normal ratio is about 2:1 in favour of +KTS, and in Frasier syndrome it is
roughly inverted. The imbalance has been demonstrated directly in patient
tissue.
downstream:
- target: Failure of Testis Determination
causal_link_type: DIRECT
evidence:
- reference: PMID:9499425
reference_title: "Frasier syndrome is caused by defective alternative splicing of WT1 leading to an altered ratio of WT1 +/-KTS splice isoforms."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "gonadal development may be particularly sensitive to imbalance or relative underrepresentation of the WT1 +KTS isoform"
explanation: Attributes the gonadal phenotype specifically to the isoform imbalance.
- reference: PMID:35894442
reference_title: "Monogenic focal segmental glomerulosclerosis: A conceptual framework for identification and management of a heterogeneous disease."
supports: SUPPORT
evidence_source: MODEL_ORGANISM
snippet: "heterozygous mice with reduced expression of the +KTS isoform develop glomerulosclerosis while homozygous mice lacking +KTS have complete XY sex reversal"
explanation: >-
Mouse models separate the dose of the +KTS isoform from any other WT1
defect and reproduce the gonadal branch: homozygous loss of +KTS gives complete XY sex reversal, which is direct support for this edge
rather than for either node alone.
- target: Podocyte Dysfunction and Segmental Glomerular Scarring
causal_link_type: DIRECT
evidence:
- reference: PMID:35894442
reference_title: "Monogenic focal segmental glomerulosclerosis: A conceptual framework for identification and management of a heterogeneous disease."
supports: SUPPORT
evidence_source: MODEL_ORGANISM
snippet: "heterozygous mice with reduced expression of the +KTS isoform develop glomerulosclerosis while homozygous mice lacking +KTS have complete XY sex reversal"
explanation: >-
Mouse models separate the dose of the +KTS isoform from any other WT1
defect and reproduce the renal branch: heterozygous reduction of +KTS produces glomerulosclerosis, which is direct support for this edge
rather than for either node alone.
evidence:
- reference: PMID:9398852
reference_title: "Donor splice-site mutations in WT1 are responsible for Frasier syndrome."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "Examination of WT1 transcripts indeed showed a diminution of the +KTS/-KTS isoform ratio in patients with FS."
explanation: Demonstrates the isoform ratio shift in patients.
- reference: PMID:9499425
reference_title: "Frasier syndrome is caused by defective alternative splicing of WT1 leading to an altered ratio of WT1 +/-KTS splice isoforms."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "The splice mutation leads to an imbalance of WT1 isoforms in vivo"
explanation: Confirms the imbalance in patient tissue rather than only in prediction.
- reference: PMID:39698353
reference_title: "Clinical Characterization of a National Cohort of Patients With Germline WT1 Variants Including Late-Onset Phenotypes."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "Intron 9 splice-site variants induce an unbalanced production of WT1 isoforms with and without the KTS amino acids at the end of exon 9, normally expressed in a 2:1 +KTS: −KTS ratio in the kidney."
explanation: >-
Gives the normal kidney isoform ratio the lesion perturbs, which is what
makes the imbalance quantitative rather than qualitative.
- name: Failure of Testis Determination
biological_scale: TISSUE
description: >-
The 46,XY gonad does not undergo testicular differentiation, leaving bilateral
streak gonads and, in the absence of androgen and anti-Mullerian hormone,
female external genitalia.
downstream:
- target: Streak gonad
evidence:
- reference: PMID:9398852
reference_title: "Donor splice-site mutations in WT1 are responsible for Frasier syndrome."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "Patients present with normal female external genitalia, streak gonads and XY karyotype and frequently develop gonadoblastoma."
explanation: >-
The streak gonad is the direct morphological result of the gonad
failing to differentiate as a testis.
- target: Sex reversal
evidence:
- reference: PMID:9398852
reference_title: "Donor splice-site mutations in WT1 are responsible for Frasier syndrome."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "Patients present with normal female external genitalia, streak gonads and XY karyotype and frequently develop gonadoblastoma."
explanation: >-
Female external genitalia in a 46,XY individual follow from the absent
androgen and anti-Mullerian hormone output of the undifferentiated
gonad.
- target: Gonadal dysgenesis
evidence:
- reference: PMID:36980135
reference_title: "Frasier Syndrome: A 15-Year-Old Phenotypically Female Adolescent Presenting with Delayed Puberty and Nephropathy."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "Frasier syndrome (FS) is a rare inherited disorder characterized by gonadal dysgenesis and progressive nephropathy, resulting from mutations in the intron 9 splice donor site of the Wilms tumor 1 (WT1) gene."
explanation: >-
Names gonadal dysgenesis as a defining consequence of the intron 9
lesion.
- target: Gonadoblastoma
evidence:
- reference: PMID:36980135
reference_title: "Frasier Syndrome: A 15-Year-Old Phenotypically Female Adolescent Presenting with Delayed Puberty and Nephropathy."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "Gonadoblastoma usually occurs in the second decade of life but can develop as early as 9 months of age in children with gonadal dysgenesis"
explanation: >-
Ties gonadoblastoma risk specifically to the dysgenetic gonad, which
is what makes this an edge from failed testis determination rather
than an independent tumor predisposition.
- target: Primary amenorrhea
evidence:
- reference: PMID:25623218
reference_title: "Gonadal tumor in Frasier syndrome: a review and classification."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "Although type 1 is noticed at the mean age of 16 due to mainly primary amenorrhea, type 2 and 3 do not present delayed secondary sex characteristics, making diagnosis difficult."
explanation: >-
Primary amenorrhea follows from the absent gonadal endocrine output,
and is the usual presenting sign in the classic group.
- target: Delayed puberty
evidence:
- reference: PMID:36980135
reference_title: "Frasier Syndrome: A 15-Year-Old Phenotypically Female Adolescent Presenting with Delayed Puberty and Nephropathy."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "This is the first case of FS with delayed puberty as the first complaint with no previous renal symptoms."
explanation: >-
Delayed puberty can be the sole initial manifestation of the gonadal
failure, before any renal involvement.
- target: Hypergonadotropic hypogonadism
evidence:
- reference: PMID:32352694
reference_title: "WT1 Disorder."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "In adulthood, most individuals are affected by early gonadal insufficiency of variable severity with potential impact on puberty and fertility."
explanation: >-
Gonadal insufficiency is the endocrine expression of the failed testis
determination in most affected adults.
evidence:
- reference: PMID:9398852
reference_title: "Donor splice-site mutations in WT1 are responsible for Frasier syndrome."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "Patients present with normal female external genitalia, streak gonads and XY karyotype and frequently develop gonadoblastoma."
explanation: Describes the gonadal and genital consequences of failed testis determination.
- name: Podocyte Dysfunction and Segmental Glomerular Scarring
biological_scale: CELLULAR
description: >-
WT1 is required for podocyte maintenance. Isoform imbalance produces a
non-immune glomerulopathy that appears as focal and segmental sclerosis and
is therefore unresponsive to steroids.
cell_types:
- preferred_term: podocyte
term:
id: CL:0000653
label: podocyte
downstream:
- target: Proteinuria
evidence:
- reference: PMID:9398852
reference_title: "Donor splice-site mutations in WT1 are responsible for Frasier syndrome."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "Glomerular symptoms consist of childhood proteinuria and nephrotic syndrome, characterized by unspecific focal and segmental glomerular sclerosis, progressing to end-stage renal failure in adolescence or early adulthood."
explanation: >-
Proteinuria is the first clinical expression of the podocyte injury.
- target: Focal segmental glomerulosclerosis
evidence:
- reference: PMID:9398852
reference_title: "Donor splice-site mutations in WT1 are responsible for Frasier syndrome."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "Glomerular symptoms consist of childhood proteinuria and nephrotic syndrome, characterized by unspecific focal and segmental glomerular sclerosis, progressing to end-stage renal failure in adolescence or early adulthood."
explanation: >-
Segmental sclerosis is the histological lesion the podocyte injury
produces.
- target: Steroid-resistant nephrotic syndrome
evidence:
- reference: PMID:36980135
reference_title: "Frasier Syndrome: A 15-Year-Old Phenotypically Female Adolescent Presenting with Delayed Puberty and Nephropathy."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "It develops during childhood and presents with persistent proteinuria followed by steroid-resistant nephrotic syndrome (SRNS)"
explanation: >-
States the progression from proteinuria to steroid-resistant nephrotic
syndrome, the non-immune character of which is why steroids do not
work.
- target: Stage 5 chronic kidney disease
evidence:
- reference: PMID:39698353
reference_title: "Clinical Characterization of a National Cohort of Patients With Germline WT1 Variants Including Late-Onset Phenotypes."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "All patients with intron 9 splice-site variants developed CKD, at a median age of 15 years, and 2 of 3 patients with other splice-site variants developed CKD, at a median age of 6 months."
explanation: >-
Establishes that the podocyte lesion proceeds to chronic kidney
disease in every intron 9 patient followed, with adolescent median
onset.
evidence:
- reference: PMID:9398852
reference_title: "Donor splice-site mutations in WT1 are responsible for Frasier syndrome."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "Glomerular symptoms consist of childhood proteinuria and nephrotic syndrome, characterized by unspecific focal and segmental glomerular sclerosis, progressing to end-stage renal failure in adolescence or early adulthood."
explanation: Establishes the renal course from proteinuria through segmental sclerosis to end stage disease.
phenotypes:
- name: Sex reversal
description: >-
46,XY individuals have normal female external genitalia.
phenotype_term:
preferred_term: Sex reversal
term:
id: HP:0012245
label: Sex reversal
evidence:
- reference: PMID:9398852
reference_title: "Donor splice-site mutations in WT1 are responsible for Frasier syndrome."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "Patients present with normal female external genitalia, streak gonads and XY karyotype"
explanation: Documents female external genitalia with an XY karyotype.
- name: Streak gonad
description: Bilateral streak gonads replace differentiated testicular tissue.
phenotype_term:
preferred_term: Streak gonad
term:
id: HP:0025733
label: Streak gonad
evidence:
- reference: PMID:9398852
reference_title: "Donor splice-site mutations in WT1 are responsible for Frasier syndrome."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "Patients present with normal female external genitalia, streak gonads and XY karyotype"
explanation: Documents streak gonads as a defining feature.
- name: Gonadal dysgenesis
description: Complete gonadal dysgenesis, as distinct from the partial dysgenesis more typical of Denys-Drash syndrome.
phenotype_term:
preferred_term: Gonadal dysgenesis
term:
id: HP:0000133
label: Gonadal dysgenesis
evidence:
- reference: PMID:9499425
reference_title: "Frasier syndrome is caused by defective alternative splicing of WT1 leading to an altered ratio of WT1 +/-KTS splice isoforms."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "Frasier syndrome, characterized by focal glomerular sclerosis, delayed kidney failure and complete gonadal dysgenesis"
explanation: States that the gonadal dysgenesis of Frasier syndrome is complete.
- name: Gonadoblastoma
description: >-
The dysgenetic gonad carries a high risk of gonadoblastoma, which is the basis
for prophylactic gonadectomy.
frequency: FREQUENT
phenotype_term:
preferred_term: Gonadoblastoma
term:
id: HP:0000150
label: Gonadoblastoma
evidence:
- reference: PMID:25623218
reference_title: "Gonadal tumor in Frasier syndrome: a review and classification."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "The prevalence of gonadal tumor is high in type 1 (67%)"
explanation: >-
Gives a Frasier-specific gonadal tumor rate of 67% in the classic 46,XY
female-phenotype group, from a review of 88 cases. 67% falls in the
FREQUENT band, and the figure is scoped to Frasier syndrome rather than to
the wider WT1 spectrum.
- reference: PMID:9398852
reference_title: "Donor splice-site mutations in WT1 are responsible for Frasier syndrome."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "Patients present with normal female external genitalia, streak gonads and XY karyotype and frequently develop gonadoblastoma."
explanation: Documents gonadoblastoma as a frequent complication.
- name: Proteinuria
description: Childhood onset proteinuria is usually the first renal manifestation.
phenotype_term:
preferred_term: Proteinuria
term:
id: HP:0000093
label: Proteinuria
evidence:
- reference: PMID:9398852
reference_title: "Donor splice-site mutations in WT1 are responsible for Frasier syndrome."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "Glomerular symptoms consist of childhood proteinuria and nephrotic syndrome"
explanation: Documents childhood proteinuria as the presenting renal feature.
- name: Focal segmental glomerulosclerosis
description: >-
The characteristic renal lesion, distinguishing Frasier syndrome from the
diffuse mesangial sclerosis of Denys-Drash syndrome.
phenotype_term:
preferred_term: Focal segmental glomerulosclerosis
term:
id: HP:0000097
label: Focal segmental glomerulosclerosis
evidence:
- reference: PMID:9398852
reference_title: "Donor splice-site mutations in WT1 are responsible for Frasier syndrome."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "characterized by unspecific focal and segmental glomerular sclerosis"
explanation: Names the characteristic glomerular lesion.
- name: Steroid-resistant nephrotic syndrome
description: >-
The glomerulopathy is genetic rather than immune mediated and does not respond
to steroids.
phenotype_term:
preferred_term: Steroid-resistant nephrotic syndrome
term:
id: HP:0012588
label: Steroid-resistant nephrotic syndrome
evidence:
- reference: PMID:32352694
reference_title: "WT1 Disorder."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "steroid-resistant nephrotic syndrome (SRNS), a progressive glomerulopathy that does not respond to standard steroid therapy"
explanation: GeneReviews defines the steroid resistant glomerulopathy of the WT1 spectrum.
- name: Stage 5 chronic kidney disease
description: >-
Progression to end stage kidney disease occurs in adolescence or early
adulthood, later than in Denys-Drash syndrome.
phenotype_term:
preferred_term: Stage 5 chronic kidney disease
term:
id: HP:0003774
label: Stage 5 chronic kidney disease
evidence:
- reference: PMID:9398852
reference_title: "Donor splice-site mutations in WT1 are responsible for Frasier syndrome."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "progressing to end-stage renal failure in adolescence or early adulthood"
explanation: Documents the timing of end stage kidney disease.
- name: Primary amenorrhea
description: >-
Failure to menstruate in a phenotypically female adolescent. In the classic
46,XY form this is the usual reason the diagnosis is first considered.
phenotype_term:
preferred_term: Primary amenorrhea
term:
id: HP:0000786
label: Primary amenorrhea
evidence:
- reference: PMID:25623218
reference_title: "Gonadal tumor in Frasier syndrome: a review and classification."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "Although type 1 is noticed at the mean age of 16 due to mainly primary amenorrhea, type 2 and 3 do not present delayed secondary sex characteristics, making diagnosis difficult."
explanation: >-
Identifies primary amenorrhea as the presenting feature of the classic
46,XY female-phenotype group, and bounds it to that group.
- name: Delayed puberty
description: >-
Absent or arrested pubertal development, which may precede any renal
complaint.
phenotype_term:
preferred_term: Delayed puberty
term:
id: HP:0000823
label: Delayed puberty
evidence:
- reference: PMID:36980135
reference_title: "Frasier Syndrome: A 15-Year-Old Phenotypically Female Adolescent Presenting with Delayed Puberty and Nephropathy."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "This is the first case of FS with delayed puberty as the first complaint with no previous renal symptoms."
explanation: >-
Documents delayed puberty as a presenting feature that can precede renal
disease entirely, which is why it belongs on the entry.
- name: Hypergonadotropic hypogonadism
description: >-
Gonadal insufficiency with elevated gonadotropins, reflecting the absent
endocrine output of the streak gonad.
phenotype_term:
preferred_term: Hypergonadotropic hypogonadism
term:
id: HP:0000815
label: Hypergonadotropic hypogonadism
evidence:
- reference: PMID:32352694
reference_title: "WT1 Disorder."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "In adulthood, most individuals are affected by early gonadal insufficiency of variable severity with potential impact on puberty and fertility."
explanation: >-
GeneReviews puts gonadal insufficiency in most individuals in adulthood,
well above the threshold for inclusion.
progression:
- phase: Recognition
age_range: Adolescence
notes: >-
The classic 46,XY female-phenotype form is typically recognised in
adolescence, when primary amenorrhea prompts investigation, by which point
nephropathy is often already established.
evidence:
- reference: PMID:25623218
reference_title: "Gonadal tumor in Frasier syndrome: a review and classification."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "Although type 1 is noticed at the mean age of 16 due to mainly primary amenorrhea"
explanation: Gives the mean age and usual trigger of recognition for the classic presentation.
genetic:
- name: WT1 intron 9 donor splice site variants
association: Causative heterozygous splice variant
relationship_type: CAUSATIVE
variant_origin: GERMLINE
gene_term:
preferred_term: WT1
term:
id: hgnc:12796
label: WT1
features: >-
Heterozygous point variants at the intron 9 donor splice site, preferentially
at a CpG dinucleotide, abolish +KTS isoform production from the mutant allele
without generating an abnormal protein.
evidence:
- reference: PMID:9499425
reference_title: "Frasier syndrome is caused by defective alternative splicing of WT1 leading to an altered ratio of WT1 +/-KTS splice isoforms."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "is probably caused by specific intronic point mutations of WT1 that preferentially affect a CpG dinucleotide"
explanation: Characterises the causative variant class.
treatments:
- name: RAAS Inhibition for Proteinuria
description: >-
Renin angiotensin aldosterone system blockade is used to reduce proteinuria.
treatment_term:
preferred_term: Pharmacotherapy
term:
id: NCIT:C15986
label: Pharmacotherapy
therapeutic_modality: SMALL_MOLECULE
target_mechanisms:
- target: Podocyte Dysfunction and Segmental Glomerular Scarring
evidence:
- reference: PMID:32352694
reference_title: "WT1 Disorder."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "SRNS: avoid immunosuppressants; consider renin-angiotensin-aldosterone system (RAAS) inhibition."
explanation: GeneReviews management recommendation for the glomerulopathy.
- name: Avoidance of Immunosuppressive Therapy
description: >-
An explicit agents to avoid recommendation. Immunosuppressants given
empirically for steroid resistant nephrotic syndrome are ineffective here and
carry toxicity, which is a practical reason to establish the WT1 genotype
early.
treatment_term:
preferred_term: Supportive Care
term:
id: NCIT:C15747
label: Supportive Care
evidence:
- reference: PMID:32352694
reference_title: "WT1 Disorder."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "Avoid treating glomerulopathy with immunosuppressants, as they are not effective and potentially toxic."
explanation: The GeneReviews agents to avoid recommendation, quoted directly.
- name: Prophylactic Gonadectomy
description: >-
Removal of the dysgenetic gonads prevents gonadoblastoma. The indication is
karyotype dependent: gonadal tumor risk is concentrated in 46,XY individuals,
and a review of 88 cases found no gonadal tumor in the 46,XX group, in whom
preventive gonadectomy is therefore not indicated.
treatment_term:
preferred_term: Surgical Procedure
term:
id: NCIT:C15329
label: Surgical Procedure
target_mechanisms:
- target: Failure of Testis Determination
evidence:
- reference: PMID:32352694
reference_title: "WT1 Disorder."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "Prevent whenever possible gonadoblastoma by prophylactic gonadectomy in those with a disorder of testicular development."
explanation: GeneReviews recommends prophylactic gonadectomy for gonadoblastoma prevention.
- reference: PMID:25623218
reference_title: "Gonadal tumor in Frasier syndrome: a review and classification."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "which emphasize that preventive gonadectomy is unnecessary in type 3"
explanation: >-
Bounds the recommendation. Type 3 is the 46,XX female-phenotype group, in
which no gonadal tumor was observed, so the prophylactic indication does
not extend to it.
- name: Kidney Transplantation
description: >-
Definitive treatment for the end stage kidney disease, and reported to be
effective here. A mechanistic expectation is often stated alongside it: the
lesion is genetic and intrinsic to the native podocyte, so a graft does not
carry the defect, unlike primary FSGS where post-transplant recurrence is a
major concern. That expectation is not directly evidenced in the sources
cited here, which report graft survival but do not attribute the graft
losses, so it is given as rationale rather than as an outcome claim.
treatment_term:
preferred_term: Kidney Transplantation
term:
id: NCIT:C15265
label: Kidney Transplantation
target_mechanisms:
- target: Podocyte Dysfunction and Segmental Glomerular Scarring
evidence:
- reference: DOI:10.3389/fped.2022.847295
reference_title: "Spectrum of Clinical Manifestations in Children With WT1 Mutation: Case Series and Literature Review"
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "All progressed to end-stage kidney disease (ESKD) and received a kidney transplant at a median age of 5 years (1.5–15 years)."
explanation: >-
Documents transplantation as the endpoint of management. Note the cohort
is WT1 spectrum-wide rather than Frasier-specific, with a median
presentation of 0.9 years, so the median transplant age of 5 years cannot
be read as a Frasier figure.
- reference: DOI:10.3389/fped.2022.847295
reference_title: "Spectrum of Clinical Manifestations in Children With WT1 Mutation: Case Series and Literature Review"
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "During a median time of follow-up of 9 years (range 2–28 years), there were 2 allograft losses after 7 and 10 years and no evidence of post-transplant malignancy."
explanation: >-
Long follow-up in a spectrum-wide cohort. The two allograft losses are not
attributed to a cause in the source, so this is not evidence about
recurrence either way.
- reference: PMID:36980135
reference_title: "Frasier Syndrome: A 15-Year-Old Phenotypically Female Adolescent Presenting with Delayed Puberty and Nephropathy."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "For these patients, kidney transplantation has been reported to be effective."
explanation: >-
States the effectiveness claim itself, in a Frasier syndrome paper.
- name: Dialysis
description: >-
Kidney replacement therapy once end stage disease is reached and before or
instead of transplantation. GeneReviews notes one procedural caveat specific
to this spectrum, that diaphragmatic hernia should be repaired before
peritoneal dialysis is started.
treatment_term:
preferred_term: Dialysis
term:
id: NCIT:C15221
label: Dialysis
target_mechanisms:
- target: Podocyte Dysfunction and Segmental Glomerular Scarring
evidence:
- reference: PMID:32352694
reference_title: "WT1 Disorder."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "Diaphragmatic hernia repair prior to the start of peritoneal dialysis."
explanation: >-
The only dialysis-specific management point GeneReviews makes for this
spectrum. It presupposes dialysis rather than evidencing its use.
- reference: PMID:36980135
reference_title: "Frasier Syndrome: A 15-Year-Old Phenotypically Female Adolescent Presenting with Delayed Puberty and Nephropathy."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "The patient is presently undergoing regular hemodialysis and preparing for kidney transplantation."
explanation: >-
Documents dialysis actually being used, as the bridge to transplantation,
in a Frasier syndrome patient.
- name: Hormone Replacement Therapy
description: >-
The streak gonad produces no sex steroids, so replacement is needed to induce
and maintain secondary sexual characteristics, both after prophylactic
gonadectomy and in those presenting with gonadal insufficiency.
treatment_term:
preferred_term: Hormone Replacement Therapy
term:
id: NCIT:C15599
label: Hormone Replacement Therapy
target_mechanisms:
- target: Failure of Testis Determination
evidence:
- reference: PMID:32352694
reference_title: "WT1 Disorder."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "In adulthood, most individuals are affected by early gonadal insufficiency of variable severity with potential impact on puberty and fertility."
explanation: >-
Establishes the gonadal insufficiency that replacement therapy addresses.
GeneReviews assigns the management itself to a multidisciplinary team
including an endocrinologist rather than naming a regimen.
- reference: PMID:36980135
reference_title: "Frasier Syndrome: A 15-Year-Old Phenotypically Female Adolescent Presenting with Delayed Puberty and Nephropathy."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "In addition, hormone replacement therapy should be performed to stimulate normal puberty and to promote the development of secondary sexual characteristics."
explanation: >-
States the intervention itself, and its purpose, in a Frasier syndrome
patient rather than across the WT1 spectrum.
animal_models:
- name: WT1 +KTS isoform dosage series
species: Mouse
genotype: Wt1 +KTS heterozygous and homozygous null
publication: PMID:35894442
description: >-
A dosage series in which only the amount of the +KTS isoform is varied. This
is the experiment human genetics cannot perform: patients all carry one
splice allele, so isoform dose cannot be separated from the variant itself.
The mice separate them, and the two branches of the human phenotype appear at
different doses.
modeled_mechanisms:
- target: Podocyte Dysfunction and Segmental Glomerular Scarring
relationship: PARTIALLY_RECAPITULATES
fidelity: MODERATE
description: >-
Heterozygous reduction of +KTS, the dose closest to the human
heterozygous state, produces glomerulosclerosis.
limitations: >-
Reproduces the glomerular lesion but not the human renal time course, and
the model speaks to isoform dose rather than to the intron 9 splice
variant itself.
evidence:
- reference: PMID:35894442
reference_title: "Monogenic focal segmental glomerulosclerosis: A conceptual framework for identification and management of a heterogeneous disease."
supports: SUPPORT
evidence_source: MODEL_ORGANISM
snippet: "heterozygous mice with reduced expression of the +KTS isoform develop glomerulosclerosis while homozygous mice lacking +KTS have complete XY sex reversal"
explanation: The heterozygous arm of the dosage series gives the renal phenotype.
- target: Failure of Testis Determination
relationship: RECAPITULATES
fidelity: MODERATE
description: >-
Homozygous loss of +KTS produces complete XY sex reversal, the gonadal
branch of the human phenotype.
limitations: >-
Requires homozygous loss, whereas patients are heterozygous, so the
gonadal branch is recapitulated only at a more extreme dose than the human
genotype. Says nothing about gonadoblastoma risk or tumor histology.
evidence:
- reference: PMID:35894442
reference_title: "Monogenic focal segmental glomerulosclerosis: A conceptual framework for identification and management of a heterogeneous disease."
supports: SUPPORT
evidence_source: MODEL_ORGANISM
snippet: "heterozygous mice with reduced expression of the +KTS isoform develop glomerulosclerosis while homozygous mice lacking +KTS have complete XY sex reversal"
explanation: The homozygous arm of the dosage series gives the gonadal phenotype.
diagnosis:
- name: WT1 Molecular Genetic Testing
presence: Heterozygous WT1 intron 9 donor splice site variant
description: >-
The diagnosis rests on identifying the WT1 variant. This matters practically
because establishing the genotype early is what justifies withholding
immunosuppression for the steroid-resistant nephrotic syndrome.
evidence:
- reference: PMID:32352694
reference_title: "WT1 Disorder."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "The diagnosis of WT1 disorder is established in a proband with suggestive clinical findings and a heterozygous pathogenic variant in WT1 identified by molecular genetic testing."
explanation: The GeneReviews diagnostic criterion for the WT1 disorder spectrum.
- name: Karyotype
presence: 46,XY in the classic form; 46,XX in type 3
description: >-
Karyotype is needed because it determines the gonadal tumor risk and so
whether prophylactic gonadectomy is indicated.
evidence:
- reference: PMID:25623218
reference_title: "Gonadal tumor in Frasier syndrome: a review and classification."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "Type 1 Frasier syndrome is characterized by female external genitalia with 46,XY (n = 72); type 2 by male external genitalia with 46,XY (n = 8); and type 3 by female external genitalia with 46,XX (n = 8)."
explanation: The subtype partition, and hence the tumor risk stratification, is defined by karyotype.
- name: Proteinuria Surveillance
presence: New or rising proteinuria
description: >-
Scheduled monitoring for the first appearance of glomerular disease.
Surveillance is life-long rather than paediatric, because kidney disease in
intron 9 splice variants has a later median onset than in the missense
genotypes.
evidence:
- reference: PMID:32352694
reference_title: "WT1 Disorder."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "proteinuria every six months until age ten years, yearly thereafter"
explanation: The GeneReviews surveillance interval for glomerular disease.
- reference: PMID:39698353
reference_title: "Clinical Characterization of a National Cohort of Patients With Germline WT1 Variants Including Late-Onset Phenotypes."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "Therefore, life-long surveillance of kidney function is recommended."
explanation: >-
Extends surveillance beyond childhood, on the basis that CKD in this
cohort could begin well into adult life.
- name: Gonadal Insufficiency Surveillance
presence: Rising gonadotropins or absent pubertal progression
description: >-
Monitoring for the endocrine failure of the dysgenetic gonad, beginning
after puberty.
evidence:
- reference: PMID:32352694
reference_title: "WT1 Disorder."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "early gonadal insufficiency yearly after puberty"
explanation: The GeneReviews surveillance interval for gonadal insufficiency.
differential_diagnoses:
- name: Denys-Drash syndrome
disease_term:
preferred_term: Denys-Drash syndrome
term:
id: MONDO:0008682
label: Denys-Drash syndrome
description: >-
The other pole of the WT1 continuum. Denys-Drash syndrome arises from
dominant negative zinc finger missense variants and presents with diffuse
mesangial sclerosis, early kidney failure and a high risk of Wilms tumor.
distinguishing_features:
- Focal segmental glomerulosclerosis with kidney failure in adolescence or early adulthood favors Frasier syndrome.
- Diffuse mesangial sclerosis with early kidney failure favors Denys-Drash syndrome.
- An intron 9 donor splice site variant favors Frasier syndrome; a zinc finger missense variant favors Denys-Drash syndrome.
- Absence of Wilms tumor on extended follow-up favors Frasier syndrome.
evidence:
- reference: PMID:9398852
reference_title: "Donor splice-site mutations in WT1 are responsible for Frasier syndrome."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "No case of Wilms' tumour has been reported, even in patients with extended follow-up."
explanation: >-
Supports absence of Wilms tumor as a discriminator. This is also why the
Wilms tumor frequency of the broader WT1 disorder spectrum must not be
carried onto this entry.
- reference: PMID:9398852
reference_title: "Donor splice-site mutations in WT1 are responsible for Frasier syndrome."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "Renal symptoms are characterized by diffuse mesangial sclerosis, usually before the age of one year, and patients frequently develop Wilms' tumour."
explanation: Describes the contrasting Denys-Drash renal lesion and tumor risk.
- reference: PMID:39698353
reference_title: "Clinical Characterization of a National Cohort of Patients With Germline WT1 Variants Including Late-Onset Phenotypes."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "Wilms tumor was reported in 18 of 19 patients with truncating variants, all with deletions, 2 of 13 with missense variants, and 2 of 7 with splice-site variants (not in patients with intron 9 variants)."
explanation: >-
Modern genotype-stratified corroboration in a national cohort. No Wilms
tumor occurred in any intron 9 patient, against 18 of 19 with truncating
variants, so the discriminator is measured directly rather than inferred
from the absence of case reports.
- reference: PMID:39698353
reference_title: "Clinical Characterization of a National Cohort of Patients With Germline WT1 Variants Including Late-Onset Phenotypes."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "All patients with intron 9 splice-site variants developed CKD, at a median age of 15 years, and 2 of 3 patients with other splice-site variants developed CKD, at a median age of 6 months."
explanation: >-
Quantifies the intron 9 renal course and separates it from other
splice-site variants, whose kidney disease begins in infancy. Supports
adolescent-onset kidney failure as the discriminating feature.
discussions:
- discussion_id: nosology_frasier_denys_drash_continuum
prompt: >-
Should Frasier syndrome be curated as a disease at all, given that the
current GeneReviews chapter has retired it as a clinical designation in
favour of a single WT1 disorder continuum?
kind: INTERPRETATION
status: OPEN
attaches_to:
- pathophysiology#WT1 Intron 9 Donor Splice Site Variants
- differential_diagnoses#Denys-Drash syndrome
rationale: >-
The entry is curated because MONDO carries the term, the historical
literature is indexed under it, and the intron 9 splice mechanism is
genuinely distinct in kind from the dominant negative zinc finger missense
lesion at the other pole. The counter-argument is that the two poles differ
quantitatively along one axis rather than being separate diseases, and that
a continuum is the better model. Both readings are represented in the
literature and the question is not settled here.
evidence:
- reference: PMID:10762296
reference_title: "Frasier syndrome, part of the Denys Drash continuum or simply a WT1 gene associated disorder of intersex and nephropathy?"
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "The case provides a focus for the discussion of recent evidence that Denys Drash and Frasier syndrome form two ends of a spectrum of disorders."
explanation: >-
States the continuum position directly, and is the source the entry's
nosological framing argues from alongside GeneReviews.
- reference: PMID:32352694
reference_title: "WT1 Disorder."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "those designations are now recognized to be part of a phenotypic continuum and are no longer clinically helpful"
explanation: The current GeneReviews position, which retires the eponym.
- discussion_id: curation_gap_wt1_counterpart_entries
prompt: >-
The Denys-Drash counterpart entry and a WT1 disorder grouping do not exist
in this knowledge base. Should they be curated so the continuum can be
represented explicitly rather than described in prose?
kind: CURATION_TODO
status: OPEN
attaches_to:
- differential_diagnoses#Denys-Drash syndrome
rationale: >-
Much of this entry's framing is comparative, and the comparison currently
points at an entry that is not there. MONDO:0008682 appears only as a
differential-diagnosis reference. Until the counterpart is curated, a reader
cannot follow the contrast, and the continuum has no machine-readable
representation.
notes: >-
Frequency bands are deliberately omitted. The GeneReviews chapter that covers
this disease is scoped to WT1 disorder as a whole, so its frequency language
("common findings can include ... Wilms tumor") describes the whole spectrum
and not Frasier syndrome, where Wilms tumor is characteristically absent.
Carrying those bands across the scope boundary is the defect tracked in #6951.
Frasier-specific frequencies should be added from a Frasier cohort rather than
inherited from the spectrum.
references:
- reference: PMID:32352694
title: "WT1 Disorder."
tags:
- GeneReviews
Deep research results are used as seeds for research; they do not undergo the same validation as the main records and may contain errors. How we use deep research.
Create: Frasier Syndrome · 2026-09-03T14:03:30Z · View source
De novo curation of Frasier syndrome (MONDO:0007635) from a falcon deep-research report. Built the causal graph around the WT1 intron 9 donor splice-site lesion: the mutant allele cannot make the +KTS isoform, the resulting +KTS/-KTS imbalance drives both failure of testis determination and podocyte injury with segmental glomerular scarring. All three mechanism-to-mechanism edges carry edge-level evidence; the gonadal and renal branches are supported by a WT1 +KTS mouse dosage series. Validated with just validate: schema, terms, and 32/32 evidence snippets verified against cached references. Following two rounds of automated review, the entry was extended with has_subtypes for the type 1-3 partition, a diagnosis section including surveillance, an animal_models entry for the WT1 +KTS mouse dosage series, GO and CL annotation, three endocrine phenotypes and three further treatments. Every causal edge is now cited: 15 of 15, up from 3 of 12 at open, and 69 snippets verify against cached references.
Frasier syndrome (FS) is an ultra-rare, autosomal-dominant WT1 disorder, usually caused by heterozygous germline variants affecting the intron-9 alternative splice donor. Its defining clinical combination is progressive proteinuric glomerulopathy—usually steroid-resistant nephrotic syndrome (SRNS) with focal segmental glomerulosclerosis (FSGS)—and gonadal dysgenesis, especially in 46,XY individuals, with a clinically important risk of gonadoblastoma. Contemporary experts increasingly regard Frasier and Denys–Drash syndromes as overlapping ends of a continuous WT1-disorder spectrum rather than completely discrete entities. (shao2023frasiersyndromea pages 1-2, sambharia2022monogenicfocalsegmental pages 11-12, peer2024clinicalcharacterizationof pages 7-9)
The most important recent development is recognition of a wider and temporally variable WT1 phenotype. A 2024 Dutch national cohort found that all four individuals with intron-9 splice variants developed chronic kidney disease (CKD), with median onset at 15 years, while other WT1 variant classes could cause kidney failure as late as adulthood. This supports lifelong renal surveillance and full-gene testing rather than reliance on classical syndrome labels or hotspot-only sequencing. (peer2024clinicalcharacterizationof pages 1-2, peer2024clinicalcharacterizationof pages 2-4, peer2024clinicalcharacterizationof pages 7-9)
The following table provides a knowledge-base-oriented synopsis; broader WT1-spectrum statistics are identified as such rather than presented as Frasier-specific rates.
| 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. (shao2023frasiersyndromea pages 1-2, peer2024clinicalcharacterizationof pages 7-9) | 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. (shao2023frasiersyndromea pages 2-4) | A 2023 patient had de novo NM_024426.6:c.1447+4C>T, absent in both parents and a sibling. (shao2023frasiersyndromea pages 2-4) | 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. (paul2021suspicionoffrasiers pages 4-7, peer2024clinicalcharacterizationof pages 2-4) | 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. (peer2024clinicalcharacterizationof pages 2-4) | 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. (shao2023frasiersyndromea pages 1-2, shao2023frasiersyndromea pages 2-4) | 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. (shao2023frasiersyndromea pages 1-2, sambharia2022monogenicfocalsegmental pages 11-12) | 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. (paul2021suspicionoffrasiers pages 4-7, peer2024clinicalcharacterizationof pages 2-4, peer2024clinicalcharacterizationof pages 4-6) | 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. (sambharia2022monogenicfocalsegmental pages 11-12, peer2024clinicalcharacterizationof pages 6-7) | 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. (peer2024clinicalcharacterizationof pages 2-4) | 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. (shao2023frasiersyndromea pages 2-4, paul2021suspicionoffrasiers pages 4-7) | 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. (shao2023frasiersyndromea pages 1-2, drayer2022spectrumofclinical pages 6-8) | 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. (sambharia2022monogenicfocalsegmental pages 11-12, peer2024clinicalcharacterizationof pages 4-6) | 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. (lipska2014genotypephenotypeassociationsin pages 8-9, peer2024clinicalcharacterizationof pages 4-6) | 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. (peer2024clinicalcharacterizationof pages 2-4) | In the 2024 cohort, Wilms tumor occurred in 26/43 overall, but in 0/4 intron 9 splice-variant cases; ascertainment was phenotype-biased. (peer2024clinicalcharacterizationof pages 2-4) | 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. (shao2023frasiersyndromea pages 1-2, drayer2022spectrumofclinical pages 10-11) | 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. (peer2024clinicalcharacterizationof pages 2-4, peer2024clinicalcharacterizationof pages 7-9) | 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. (sambharia2022monogenicfocalsegmental pages 11-12, drayer2022spectrumofclinical pages 10-11) | 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. (shao2023frasiersyndromea pages 2-4, drayer2022spectrumofclinical pages 1-2) | 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. (shao2023frasiersyndromea pages 1-2, drayer2022spectrumofclinical pages 1-2) | 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. (drayer2022spectrumofclinical pages 1-2, peer2024clinicalcharacterizationof pages 1-2) | 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. (lipska2014genotypephenotypeassociationsin pages 8-9) | 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. (sambharia2022monogenicfocalsegmental pages 11-12) | 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.
FS is a Mendelian developmental and renal disorder caused by pathogenic germline WT1 variants. The classical phenotype comprises childhood-onset proteinuria progressing to CKD/ESKD, FSGS, 46,XY gonadal dysgenesis with female or atypical external genitalia, gonadal failure, and gonadoblastoma susceptibility. Less typical presentations occur in phenotypic males and 46,XX individuals. (shao2023frasiersyndromea pages 1-2, paul2021suspicionoffrasiers pages 4-7, kitsioutzeli2012sertolicelltumor pages 7-7)
Suggested identifiers are OMIM 136680 and ORPHA:347. A current MONDO identifier should be verified directly against the production MONDO release before ingestion; the retrieved primary literature did not state one. No dedicated ICD-10-CM code exists: coding ordinarily combines congenital gonadal-development, nephrotic/CKD, and genetic-condition codes. ICD-11 and MeSH similarly tend to represent the component phenotypes or broader WT1-related disorder rather than a uniquely granular FS entity.
Synonyms include Frasier syndrome, Frasier’s syndrome, WT1-related Frasier syndrome, and historically “46,XY male pseudohermaphroditism with progressive glomerulopathy.” The latter terminology is obsolete and potentially stigmatizing; 46,XY difference/disorder of sex development (DSD) or 46,XY gonadal dysgenesis is preferred.
Evidence is predominantly aggregated disease-level literature, retrospective WT1 cohorts, systematic case compilations, and individual case reports. It is not primarily derived from routine EHR population studies.
A useful exact abstract statement from Shao et al. (published 17 March 2023; DOI: https://doi.org/10.3390/children10030577) is: “Frasier syndrome (FS) is a rare inherited disorder characterized by gonadal dysgenesis and progressive nephropathy, resulting from mutations in the intron 9 splice donor site of the Wilms tumor 1 (WT1) gene.” (shao2023frasiersyndromea pages 1-2)
The causal lesion is a heterozygous germline WT1 variant, classically at nucleotides +4 or +5 of intron 9. A recurrent example is NM_024426.6:c.1447+4C>T, historically IVS9+4C>T. A 2023 patient carried this variant; neither parent nor a sibling carried it, supporting a de novo event. The disorder is nevertheless autosomal dominant, so an affected individual has a theoretical 50% transmission probability, subject to reproductive capacity and variant-specific expression. (shao2023frasiersyndromea pages 2-4)
Variants outside the canonical intron-9 donor can produce overlapping phenotypes. Thus, a patient with WT1-associated FSGS and DSD should not be excluded merely because the genotype or presentation is nonclassical. The 2014 cohort found that 28% of mutation-positive patients initially appeared to have isolated sporadic SRNS and another 28% had extrarenal findings recognized only after genotype-directed examination. (lipska2014genotypephenotypeassociationsin pages 8-9)
Pathogenic FS variants are expected to be absent or exceptionally rare in population databases, but allele-level gnomAD frequency and ClinVar classification should be checked against the exact transcript and genome build. No reliable carrier-frequency, founder-effect, anticipation, or population-specific enrichment estimate is available.
No toxin, infection, lifestyle, diet, occupation, or prenatal exposure has been shown to cause FS. Environmental factors may affect general CKD progression but are not established FS etiologies. No validated protective allele, modifier gene, protective lifestyle exposure, or disease-specific gene–environment interaction has been demonstrated. Likewise, no reproducible FS-specific epigenetic signature is established. These are evidence gaps, not evidence that modifiers cannot exist.
The usual earliest recognized renal abnormality is persistent proteinuria in childhood, sometimes accompanied by edema and hypertension. Historical compilations place onset commonly between ages 2 and 10, followed by steroid-resistant nephrotic syndrome, declining glomerular filtration, CKD, and ESKD during adolescence or early adulthood. Severity and timing are variable. (paul2021suspicionoffrasiers pages 4-7)
Renal biopsy usually shows FSGS; diffuse mesangial sclerosis is possible but is more typical of early, severe WT1 disease classically labeled Denys–Drash. In the broader 2024 WT1 cohort, FSGS was confirmed in 11 patients at a median age of four years, and all ten evaluable FSGS patients progressed to kidney failure. Those figures are not FS-specific. (peer2024clinicalcharacterizationof pages 2-4, peer2024clinicalcharacterizationof pages 4-6, peer2024clinicalcharacterizationof pages 6-7)
Suggested HPO concepts include proteinuria, nephrotic syndrome, steroid-resistant nephrotic syndrome, FSGS, hypertension, renal insufficiency, CKD, and ESKD. Exact HPO identifiers should be resolved against the current HPO release.
The classical patient has a 46,XY karyotype, female external genitalia, bilateral streak or dysgenetic gonads, absent or impaired testicular differentiation, and primary gonadal failure. Delayed or absent puberty, absent secondary sexual characteristics, primary amenorrhea, and hypergonadotropic hypogonadism may be the presenting features. Phenotypic males can have cryptorchidism, hypospadias, micropenis, or ambiguous genitalia. (shao2023frasiersyndromea pages 2-4, paul2021suspicionoffrasiers pages 4-7, kitsioutzeli2012sertolicelltumor pages 7-7)
The 2023 case is clinically important because a 15-year-old phenotypic female presented first with delayed puberty; investigation then disclosed 46,XY karyotype, c.1447+4C>T, proteinuria, renal insufficiency, and FSGS. This supports karyotyping and renal evaluation in otherwise unexplained delayed puberty. (shao2023frasiersyndromea pages 2-4, shao2023frasiersyndromea pages 1-2)
Suggested HPO concepts include 46,XY sex reversal, complete/partial gonadal dysgenesis, streak gonad, cryptorchidism, hypospadias, female external genitalia in a 46,XY individual, delayed puberty, primary amenorrhea, and hypergonadotropic hypogonadism.
Dysgenetic gonads containing Y-chromosome material have substantial gonadoblastoma risk, with possible progression or coexistence with dysgerminoma. Tumors can occur in childhood, adolescence, or adulthood. In a 2014 WT1 cohort, three of nine patients with sex reversal developed gonadoblastoma; the 2024 cohort reported four gonadoblastomas, including one intron-9 patient at age 23, and intratubular germ-cell neoplasia in another intron-9 patient at age 15. These small, ascertainment-biased data should not be treated as precise penetrance estimates. (lipska2014genotypephenotypeassociationsin pages 8-9, peer2024clinicalcharacterizationof pages 4-6)
Wilms tumor belongs to the broader WT1 spectrum but appears less characteristic of classical intron-9 FS than of truncating/deletion or zinc-finger missense disorders. In the 2024 cohort, none of four intron-9 cases had Wilms tumor, whereas the overall WT1 cohort rate was 26/43; ascertainment substantially influenced that overall figure. (peer2024clinicalcharacterizationof pages 2-4)
No FS-specific EQ-5D, SF-36, or PROMIS study was identified. Likely burdens include chronic medication and monitoring, nephrotic edema, hypertension, dialysis, transplantation, infertility, gonadectomy, hormone replacement, tumor anxiety, disclosure of chromosomal findings, and psychosocial issues surrounding sex development. These require individualized, multidisciplinary and developmentally appropriate support.
WT1, located at 11p13, encodes a zinc-finger transcriptional regulator essential to kidney, podocyte, and gonadal development. Classical FS is produced by germline heterozygous splice-region variants rather than somatic variants. Somatic WT1 alterations may occur in tumors but do not by themselves establish inherited FS. (paul2021suspicionoffrasiers pages 4-7, shao2023frasiersyndromea pages 2-4)
The normal kidney expresses WT1 isoforms with and without a three-amino-acid lysine-threonine-serine insertion. The normal +KTS:−KTS ratio is approximately 2:1. Classical intron-9 variants impair the +KTS splice donor and shift the ratio toward approximately 1:2, rather than simply eliminating all WT1 protein. (paul2021suspicionoffrasiers pages 4-7, peer2024clinicalcharacterizationof pages 2-4)
The recurrent c.1447+4C>T variant is a splice-region variant predicted to disrupt donor-site recognition. Pathogenicity assessment should include phenotype concordance, segregation/de novo evidence, population absence, computational splice prediction, and—where available—RNA evidence under ACMG/AMP criteria. The precise functional label is altered isoform dosage/splicing; describing every intron-9 FS allele as simple haploinsufficiency would be incomplete.
No validated modifier gene, disease-specific methylation pattern, recurrent large chromosomal abnormality, or causal structural variant defines classical FS. Larger 11p13 deletions instead suggest WAGR-spectrum disease. Phenotypic variability among people carrying similar WT1 variants indicates that unknown modifiers probably exist, but this remains inference. (peer2024clinicalcharacterizationof pages 7-9)
Environmental toxins, radiation, pollution, smoking, diet, alcohol, exercise, occupation, and infectious agents are not established causes or triggers. Standard kidney-protective measures—blood-pressure control, avoidance of nephrotoxins, and management of cardiovascular risk—are clinically rational but do not prevent the inherited developmental defect.
The initiating splice defect is upstream; podocyte loss, sclerosis, endocrine failure, and neoplasia are downstream. No primary metabolic enzyme deficiency, ion-channel defect, infection, or systemic autoimmune process is implicated. Inflammation and fibrosis are secondary consequences of chronic tissue injury rather than the initiating lesion.
Suggested GO processes include RNA splicing, regulation of transcription by RNA polymerase II, metanephric glomerulus development, podocyte differentiation, maintenance of glomerular filtration barrier, gonad development, and sex differentiation. Suggested cell types include podocyte, gonadal somatic/supporting cell, Sertoli-lineage cell, and primordial germ cell; exact GO/CL identifiers should be validated.
No robust FS-specific single-cell, spatial-transcriptomic, proteomic, metabolomic, lipidomic, or CRISPR-screen signature was identified. These are priority research gaps.
Primary organs are the kidneys and gonads. In the kidney, the glomerulus—particularly visceral epithelial cells/podocytes—is the principal target; secondary tubulointerstitial fibrosis and whole-kidney failure follow progressive glomerular injury. In the reproductive system, dysgenetic/streak gonads and mesonephric-derived structures are affected; external genital anatomy varies. (shao2023frasiersyndromea pages 2-4, peer2024clinicalcharacterizationof pages 6-7)
Suggested anatomy terms are kidney, renal glomerulus, glomerular visceral epithelium, gonad, testis, streak gonad, uterus, and external genitalia. Suggested Cell Ontology term: podocyte. At the subcellular level WT1 primarily acts in the nucleus through its zinc-finger regulatory domains, while +KTS isoforms also have RNA-associated functions. Bilaterality is typical for gonadal dysgenesis and diffuse genetic nephropathy, although histologic sclerosis is segmental and tumor involvement may be unilateral or bilateral.
The gonadal-development lesion is prenatal/congenital, although it may remain clinically unsuspected until pubertal failure. Renal disease is generally insidious and progressive: childhood proteinuria → SRNS/FSGS → CKD → ESKD, often in the second decade, but onset and progression vary. Classical FS tends to progress more slowly than Denys–Drash syndrome. (shao2023frasiersyndromea pages 1-2, sambharia2022monogenicfocalsegmental pages 11-12)
In the 2024 national cohort, all four intron-9 patients developed CKD at a median age of 15 years. This is stronger recent evidence for later onset than older descriptions, but the subgroup is very small. Lifelong surveillance remains appropriate because WT1-associated kidney failure may occur well beyond childhood. (peer2024clinicalcharacterizationof pages 2-4, peer2024clinicalcharacterizationof pages 7-9)
There is no spontaneous remission of the genetic lesion. Proteinuria may be attenuated symptomatically, but established sclerosis is usually progressive. Critical intervention windows are: early genetic diagnosis before unnecessary immunosuppression; gonadal evaluation before neoplasia; endocrine planning before or during puberty; and CKD care before irreversible complications.
Inheritance is autosomal dominant, commonly arising de novo. Penetrance is high for some WT1-associated manifestations but is not precisely quantified for FS; expressivity is clearly variable. No anticipation is recognized. Parental germline mosaicism is theoretically possible even when blood testing is negative, so recurrence risk is low but not absolutely zero after an apparently de novo finding.
No valid population prevalence or annual incidence per 100,000 is available. No consistent geographic, ancestry, founder, or consanguinity association is established. WT1 variants accounted for approximately 6% of SRNS in one intensively studied cohort, but this is neither population prevalence nor an FS-specific percentage. (lipska2014genotypephenotypeassociationsin pages 8-9)
A conventional male:female ratio is biologically misleading because chromosomal sex, gonadal development, external phenotype, and gender identity can differ. Most classical reports concern 46,XY individuals with a female phenotype, but phenotypic males and 46,XX cases occur.
Evaluation should include urinalysis and urine protein quantification, serum creatinine/eGFR, albumin, electrolytes, blood pressure, renal ultrasonography, pubertal staging, LH/FSH and sex steroids when indicated, pelvic/gonadal ultrasonography or MRI, and chromosome analysis. Tumor-marker testing is guided by the gonadal lesion and specialist team; normal markers do not exclude gonadoblastoma.
Kidney biopsy may show FSGS and can characterize unexplained SRNS, but molecular diagnosis is decisive and biopsy is not required when the clinical-genetic diagnosis is clear. Gonadal pathology after surgery should assess gonadoblastoma, dysgerminoma, and germ-cell neoplasia.
Preferred testing is a comprehensive nephrotic-syndrome/DSD panel including WT1 or full WT1 sequencing with intron-exon boundaries plus deletion/duplication analysis. Targeted testing for c.1447+4C>T and other intron-9 donor variants is efficient when the phenotype is classic, but a negative hotspot test should be followed by full-gene analysis. WES or WGS is useful for atypical or panel-negative disease; WGS can better interrogate noncoding/structural variation. CMA or karyotype is appropriate when a larger 11p13 deletion or sex-chromosome discordance is suspected. FISH is situational. Mitochondrial and repeat-expansion testing are not routinely relevant. (peer2024clinicalcharacterizationof pages 2-4, peer2024clinicalcharacterizationof pages 7-9)
RNA analysis can demonstrate abnormal splicing and help resolve a VUS, but it is not yet routine. No validated proteomic, metabolomic, epigenomic, or liquid-biopsy diagnostic test exists.
Genetic testing and karyotyping should be prioritized in: (1) childhood SRNS/FSGS with atypical genitalia; (2) a phenotypic female with SRNS, CKD, delayed puberty, or primary amenorrhea; and (3) unexplained CKD with cryptorchidism or hypospadias. (shao2023frasiersyndromea pages 1-2, drayer2022spectrumofclinical pages 10-11)
Differentials include Denys–Drash syndrome/other WT1 disorder, WAGR syndrome, isolated genetic FSGS (e.g., NPHS1, NPHS2, LAMB2, PLCE1), complete androgen insensitivity, Swyer syndrome from other genes, 5α-reductase or 17β-HSD deficiency, NR5A1-related DSD, and Turner syndrome in a phenotypic female with pubertal failure. Denys–Drash usually has earlier, faster nephropathy, often DMS, and greater Wilms-tumor association; however, overlap is substantial and genotype should supersede rigid clinical labels. (shao2023frasiersyndromea pages 2-4, roca2009evolutivestudyof pages 5-6)
Population newborn screening is not available. Cascade testing should be offered after a familial variant is identified.
Renal prognosis without transplantation is poor: proteinuria and FSGS generally progress to ESKD. Frasier-specific five- or ten-year survival and life-expectancy estimates are unavailable. Mortality depends principally on renal failure, cardiovascular/dialysis complications, tumor development, and access to transplantation.
Kidney transplantation is effective because the molecular lesion is intrinsic to the native kidney; recurrence of genetic FSGS in the allograft is expected to be negligible. In a broader nine-child WT1 series, all underwent transplantation at a median age of five years; during median nine-year follow-up, two grafts were lost after seven and ten years and no post-transplant malignancy was observed. These outcomes cannot be assumed to represent FS alone. (drayer2022spectrumofclinical pages 1-2)
A 2021 suspected case with severe untreated ESKD died after dialysis-associated cardiac arrest, illustrating the consequences of late recognition, but molecular confirmation was absent. (paul2021suspicionoffrasiers pages 1-4)
No validated FS-specific prognostic biomarker exists beyond genotype class, age/onset of proteinuria, kidney function trajectory, renal histology, and gonadal status. The 2024 cohort supports variant class as a broad predictor but also documents substantial within-class variability. (peer2024clinicalcharacterizationof pages 1-2, peer2024clinicalcharacterizationof pages 7-9)
There is no approved disease-modifying or splice-correcting therapy.
Renal care: ACE inhibition or angiotensin-receptor blockade may reduce proteinuria and control hypertension; standard CKD care includes salt/fluid management, anemia and mineral-bone treatment, vaccination, cardiovascular-risk control, and avoidance of nephrotoxins. Because genetic WT1 podocytopathy is usually immunosuppression-resistant, prolonged corticosteroid, calcineurin-inhibitor, or other immunosuppressive trials should generally be avoided once a causal diagnosis is established. (drayer2022spectrumofclinical pages 1-2, drayer2022spectrumofclinical pages 10-11)
Kidney replacement: dialysis is used for ESKD, followed by kidney transplantation when feasible. Disease recurrence in the graft is unlikely. Native nephrectomy is individualized for severe hypertension, protein loss, tumor, or surgical considerations; prophylactic nephrectomy solely for FS is not supported by consensus. (drayer2022spectrumofclinical pages 10-11)
Gonadal management: dysgenetic gonads containing Y-chromosome material should be evaluated promptly by a multidisciplinary DSD/tumor team. Prophylactic bilateral gonadectomy is commonly recommended because surveillance cannot reliably exclude microscopic gonadoblastoma. Timing should balance malignancy risk, anatomy, hormonal function, age, assent/consent, fertility implications, and patient preferences. (sambharia2022monogenicfocalsegmental pages 11-12, lipska2014genotypephenotypeassociationsin pages 8-9)
Endocrine and psychosocial care: pubertal induction or maintenance with individualized sex-steroid replacement is used after gonadectomy or for gonadal failure. Bone health, fertility counseling, sexual health, gender identity, and psychological support are integral. A 2023 patient underwent bilateral gonadectomy but declined hormone therapy, demonstrating that real-world management requires informed shared decision-making. (shao2023frasiersyndromea pages 2-4)
Suggested NCIT intervention concepts include genetic testing, gonadectomy, hormone-replacement therapy, ACE inhibitor therapy, hemodialysis, and kidney transplantation; identifiers should be normalized against the current NCIt release. No FS-specific pharmacogenomic guidance is available.
A completed observational registry, NCT01252901, enrolled 52 people with WT1-associated diseases. No FS-specific interventional, gene-therapy, RNA-therapy, cell-therapy, or CRISPR trial was identified. Thus, no controlled response rates or FS-specific adverse-event statistics are available.
The spontaneous de novo occurrence of many variants means primary prevention is generally impossible. Genetic counseling, reproductive options—including targeted prenatal diagnosis and preimplantation genetic testing for a known familial variant—can reduce recurrence according to individual preferences.
Secondary prevention comprises early detection: cascade testing, chromosome analysis in clinically suspicious phenotypic females, early WT1 testing in SRNS/FSGS, renal surveillance, and prompt gonadal assessment. Tertiary prevention includes RAAS blockade and CKD management, avoidance of ineffective immunosuppression/nephrotoxins, timely gonadectomy to prevent gonadal malignancy, hormone replacement where appropriate, and transplantation before severe ESKD complications. No vaccine, antimicrobial prophylaxis, dietary regimen, or environmental intervention prevents FS itself.
No established naturally occurring veterinary syndrome exactly equivalent to human FS was identified. Therefore, breed associations, VBO mappings, veterinary prevalence, zoonotic potential, and cross-species transmission are not applicable. The disease is genetic and noncommunicable.
The WT1 developmental program is evolutionarily conserved, making vertebrate models informative. Relevant taxonomy includes Homo sapiens (NCBI Taxon 9606) and Mus musculus (Taxon 10090). Ortholog identifiers should be imported directly from NCBI Gene/Alliance releases rather than inferred from the literature.
The strongest disease-mechanism model is the mouse with engineered reduction or loss of the +KTS isoform. Heterozygous reduction of +KTS produces glomerulosclerosis, while homozygous absence causes complete XY sex reversal. This reproduces the two principal human mechanistic branches and strongly supports causal involvement of isoform imbalance. (sambharia2022monogenicfocalsegmental pages 11-12)
Limitations are important: engineered mice do not reproduce the full range of human renal timing, gonadoblastoma penetrance, tumor histology, endocrine management, fertility, or psychosocial outcomes. Podocyte cultures, patient-derived cells, iPSCs, and kidney/gonadal organoids could test variant-specific splicing and downstream programs, but no validated FS-specific organoid or high-throughput therapeutic platform was identified in the retrieved evidence.
The evidence base is constrained by ultra-rarity, inconsistent historical terminology, case-report enrichment, and mixing of FS with broader WT1 disorders. The 2024 national cohort is authoritative for the modern spectrum concept but includes only four intron-9 cases and is clinically ascertained. Its key conclusion—quoted from the article—is: “Therefore, life-long surveillance of kidney function is recommended.” (peer2024clinicalcharacterizationof pages 1-2, peer2024clinicalcharacterizationof pages 7-9)
Research priorities are prospective international natural-history cohorts; standardized genotype, karyotype and gonadal-pathology reporting; age-specific tumor-risk estimation; patient-reported outcomes; fertility and endocrine outcomes; single-cell studies of human podocyte and gonadal development; and variant-specific RNA/splice-correction strategies. Until those data emerge, early molecular diagnosis, multidisciplinary DSD care, gonadal tumor prevention, and planned renal replacement remain the principal real-world interventions.
References
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(drayer2022spectrumofclinical pages 1-2): Patricia Arroyo-Parejo Drayer, Wacharee Seeherunvong, Chryso P. Katsoufis, Marissa J. DeFreitas, Tossaporn Seeherunvong, Jayanthi Chandar, and Carolyn L. Abitbol. Spectrum of clinical manifestations in children with wt1 mutation: case series and literature review. Frontiers in Pediatrics, Apr 2022. URL: https://doi.org/10.3389/fped.2022.847295, doi:10.3389/fped.2022.847295. This article has 24 citations.
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(paul2021suspicionoffrasiers pages 1-4): Axler JEAN PAUL, Dieuguens LOUIS, Ansly Jefferson DESRAVINES, Raema Mimrod JEAN, Alfadler JEAN BAPTISTE, Jean Henold BUTEAU, and Wislet ANDRE. Suspicion of frasier's syndrome in the nephrology unit of the internal medicine department of the hueh: case study and review of the literature. Jun 2021. URL: https://doi.org/10.21203/rs.3.rs-622151/v1, doi:10.21203/rs.3.rs-622151/v1. This article has 0 citations.
Checked with linkml-reference-validator 0.2.1.
| Outcome | Count |
|---|---|
| References checked | 8 |
| Resolved | 8 |
| Unresolved (possible confabulation) | 0 |
| Unverifiable | 0 |
| References weighed for topical relevance | 8 |
| On topic | 3 |
| Off topic | 0 |
All extracted references resolved successfully.
Checked with linkml-term-validator 0.4.5, through the ols: adapter.
| Outcome | Count |
|---|---|
| Terms checked | 3 |
| Resolved | 0 |
| Unresolved (possible confabulation) | 0 |
| Obsolete | 0 |
| Unverifiable | 3 |
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: ORPHA, OMIM, Taxon.
No term could be looked up either way, so nothing here was confirmed or contradicted.