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Townes-Brocks syndrome (TBS) is a rare genetic disorder characterized by the triad of imperforate anus, dysplastic ears often associated with sensorineural and/or conductive hearing impairment, and thumb malformations. These features are often associated with other signs mainly affecting the kidneys and heart.
No HPO annotations are available for this condition.
SALL1-related Townes-Brocks syndrome (SALL1-TBS) is characterized by the triad of imperforate anus or anal stenosis, dysplastic ears (frequently associated with hearing impairment), and thumb malformations without hypoplasia of the radius. Impairment of kidney function may occur with or without structural abnormalities. Foot malformations, genitourinary malformations, and congenital heart disease are common. Of 165 affected individuals from 101 families with a SALL1 pathogenic variant, approximately 80% had the three major features or two major plus minor features, whereas 20% had a partial clinical expression [, , , , , , and 30 additional reports]. The following description of the phenotypic features associated with this condition is based on these reports. Some features may be underestimated due to later onset (e.g., impaired kidney function) or incomplete physical examination. Table 2. SALL1-Related Townes-Brocks Syndrome: Frequency of Select Features
Feature | % of Persons w/Feature | Comment |
|---|---|---|
Imperforate anus or anal stenosis | 70% | — |
Dysplastic ears | 87% | — |
Thumb malformations | 76% | Without hypoplasia of the radius |
Sensorineural /or conductive hearing impairment | 62% | — |
Foot malformations | 43% | — |
Kidney anomalies /or impaired kidney function | 40% | — |
Genitourinary malformations | 22% | — |
Congenital heart disease | 15% | — |
Developmental delay/ learning difficulties | 15% | Gastrointestinal manifestations include imperforate anus, anal stenosis, anteriorly placed anus, chronic constipation, and gastroesophageal reflux . Ear anomalies and hearing loss. Dysplastic ears are common, including overfolded superior helices, preauricular tags, and microtia. |
Source: GeneReviews — "SALL1-Related Townes-Brocks Syndrome"
SALL1-related Townes-Brocks syndrome (SALL1-TBS) should be suspected in individuals with the following major and minor clinical features and family history.
Major features
Imperforate anus or anal stenosis
Dysplastic ears (overfolded superior helices, preauricular tags, microtia)
Typical thumb malformations (preaxial polydactyly, triphalangeal thumbs, hypoplastic thumbs) without hypoplasia of the radius
Minor features
Sensorineural and/or conductive hearing impairment
Foot malformations
Impaired kidney function with or without kidney malformations
Genitourinary malformations
Congenital heart disease
Source: GeneReviews — "SALL1-Related Townes-Brocks Syndrome"
Table 3. Genes of Interest in the Differential Diagnosis of SALL1-Related Townes-Brocks Syndrome
Gene(s) | Disorder | MOI | Features of Disorder | Comment/ Distinguishing Features |
|---|---|---|---|---|
CCNQ | STAR syndrome (OMIM 300707) | XL | Toe syndactyly, telecanthus, anogenital renal malformations similar to TBS; Likely lethal in males | Facial features toe syndactyly distinguish STAR syndrome from SALL1-TBS. |
Biomarker and diagnostic research for Townes-Brocks syndrome has been reported in the published literature.
No approved treatments are currently available for Townes-Brocks syndrome. The disease remains an area of unmet medical need.
No clinical practice guidelines for SALL1-related Townes-Brocks syndrome (SALL1-TBS) have been published. In the absence of published guidelines, the following recommendations are based on the authors' personal experience managing individuals with this disorder.
To establish the extent of disease and needs in an individual diagnosed with SALL1-TBS, the evaluations summarized (if not performed as part of the evaluation that led to the diagnosis) are recommended.
Table 4.
SALL1-Related Townes-Brocks Syndrome: Recommended Evaluations Following Initial Diagnosis
System/Concern | Evaluation | Comment
| • Referral to surgeon for anal anomalies if present
Assessment for constipation /or gastroesophageal reflux
|
| Hearing eval (See Genetic Hearing Loss Overview.) |
| • Clinical assessment for upper- lower-extremity anomalies
Radiographs as recommended by orthopedist
| Referral to orthopedist as needed
| • Renal ultrasound
Assessment of kidney function w/serum electrolyte concentrations, BUN, creatinine
|
| Referral to urologist/gynecologist as needed |
| Eval by cardiologist w/echocardiogram |
| Developmental assessment | • To incl motor, adaptive, cognitive, speech-language eval
Eval for early intervention/ special education
Neuropsychiatric eval | For persons age 12 mos: screening for behavior concerns
| Assessment for growth deficiency | Referral to endocrinologis...
Source: GeneReviews — "SALL1-Related Townes-Brocks Syndrome"
Medications that cause renal or otic toxicity should be avoided.
Source: GeneReviews — "SALL1-Related Townes-Brocks Syndrome"
Search ClinicalTrials.gov in the US and EU Clinical Trials Register in Europe for access to information on clinical studies for a wide range of diseases and conditions. Note: There may not be clinical trials for this disorder.
Source: GeneReviews — "SALL1-Related Townes-Brocks Syndrome"
View trials for Townes-Brocks syndrome
To monitor existing manifestations, the individual's response to supportive care, and the emergence of new manifestations, the evaluations summarized in are recommended. Table 6. SALL1-Related Townes-Brocks Syndrome: Recommended Surveillance
System/Concern | Evaluation | Frequency |
|---|---|---|
Gastrointestinal | Assessment for constipation | At each visit |
Hearing | Audiology eval | Annually |
Kidney | Assessment of kidney function w/serum electrolyte concentrations, BUN, creatinine | Monitor annually in all persons w/ w/o kidney anomalies, even if no impairment of kidney function is detected on initial exam. Neurodevelopment |
Endocrine | Assessment of growth thyroid function | At each visit |
Eyes | Ophthalmology exam | Per ophthalmologist BUN = blood urea nitrogen |
Source: GeneReviews — "SALL1-Related Townes-Brocks Syndrome"
Estimated prevalence: 1-9 in 1,000,000 (Rare).
No clinical trials have been registered for Townes-Brocks syndrome.
16 publications have been identified in PubMed for Townes-Brocks syndrome. Research spans Case Report / Case Series (56%), Basic Science / Preclinical (19%), and Diagnostic / Biomarker (6%).
Research Type | Count | % of Total |
|---|---|---|
Patient case studies | 9 | 56% |
Laboratory research | 3 | 19% |
Testing and diagnosis research | 1 | 6% |
Research summaries | 1 | 6% |
Clinical study results | 1 | 6% |
Disease patterns and progression | 1 | 6% |
Tsunoda S (2026). [PMID: 42027198](https://pubmed.ncbi.nlm.nih.gov/42027198/). *Kidney Med*. [Case Report / Case Series]
Ürkmez MF (2026). [PMID: 41499068](https://pubmed.ncbi.nlm.nih.gov/41499068/). *CEN case reports*. [Case Report / Case Series]
Leduc F (2025). [PMID: 40348827](https://pubmed.ncbi.nlm.nih.gov/40348827/). *European journal of human genetics : EJHG*. [Review / Meta-Analysis]
Paripović A (2025). [PMID: 42148001](https://pubmed.ncbi.nlm.nih.gov/42148001/). *Balkan J Med Genet*. [Case Report / Case Series]
Filipič M (2025). [PMID: 40989825](https://pubmed.ncbi.nlm.nih.gov/40989825/). *Frontiers in pediatrics*. [Case Report / Case Series]
Ding X (2025). [PMID: 40616106](https://pubmed.ncbi.nlm.nih.gov/40616106/). *Orphanet journal of rare diseases*. [Case Report / Case Series]
Asagai Y (2025). [PMID: 40658219](https://pubmed.ncbi.nlm.nih.gov/40658219/). *Pediatric nephrology (Berlin, Germany)*. [Basic Science / Preclinical]
Liang R (2025). [PMID: 39910415](https://pubmed.ncbi.nlm.nih.gov/39910415/). *BMC pediatrics*. [Basic Science / Preclinical]
Sun M (2025). [PMID: 40692799](https://pubmed.ncbi.nlm.nih.gov/40692799/). *Frontiers in pediatrics*. [Clinical Trial Publication]
Acebedo AR (2025). [PMID: 40306366](https://pubmed.ncbi.nlm.nih.gov/40306366/). *Cells & development*. [Basic Science / Preclinical]
Data assembled from 4 of 12 sources · Last updated Sep 19, 2026, 4:31 PM UTC
European rare disease database
Genetic and Rare Diseases Info Center
Common questions about Townes-Brocks syndrome
DACT1 |
Townes-Brocks syndrome 2 (TBS2) (OMIM 617466) |
AD |
DACT1 pathogenic variants have been identified in families w/reduced-penetrance AD CAKUT.1 In 1 family w/loss-of-function DACT1 pathogenic variant, affected persons had CAKUT, anal, /or external ear anomalies, leading to the designation TBS2.2 |
Thumb anomalies have not been reported. EYA1 |
SIX1 | Branchiootorenal (BOR) syndrome (See Branchiootorenal Spectrum Disorder.)3 | AD | Ear malformations assoc w/hearing impairment, branchial fistulae cysts, renal malformations | In 2 families later determined to have SALL1-TBS, the presence of dysplastic ears renal malformations/ impaired kidney function initially led to consideration of BOR syndrome.; Note: No affected family members had the typical SALL1-TBS triad of thumb, anal, ear malformations.4 |
SALL4 | Duane-radial ray syndrome (DRRS, Okihiro syndrome) (See SALL4-Related Disorders.) | AD | Duane anomaly radial ray defects | In persons w/features suggestive of SALL1-TBS, both SALL1 SALL4 molecular genetic testing should be considered. SALL4 pathogenic variants have been identified in a few persons w/clinical features suggestive of SALL1-TBS. |
SF3B2 | SF3B2-related hemifacial microsomia (Goldenhar syndrome, oculo-auriculo-vertebral spectrum) (OMIM 164210) | AD | SF3B2 pathogenic variants are identified in ~3% of persons representing simplex cases (i.e., the only person w/hemifacial microsomia in a family) ~25% of individuals w/positive family history.6 | The majority of persons w/hemifacial microsomia do not have upper-limb or anal malformations. However, some persons w/SALL1 pathogenic variants have hemifacial microsomia. |
Source: GeneReviews — "SALL1-Related Townes-Brocks Syndrome"
AI-curated news mentioning Townes-Brocks syndrome
Updated Aug 28, 2026
A recent study analyzes a Chinese family affected by Townes-Brocks syndrome linked to a novel variant of the SALL1 gene. This research contributes to the understanding of genetic factors in this rare condition.