Townes-Brocks Syndrome

What it is, symptoms and effects

From: MedlinePlus Genetics, National Library of Medicine

Townes-Brocks syndrome is a genetic condition that affects several parts of the body. The most common features of this condition are a malformation of the anal opening (imperforate anus), abnormally shaped ears, and hand malformations that most often affect the thumbs. People with this condition often have at least two of these three major features.

Other signs and symptoms of Townes-Brocks syndrome can include kidney abnormalities, mild to profound hearing loss, eye abnormalities, heart defects, foot abnormalities, and genital malformations. These features vary among affected individuals, even within the same family. Mild intellectual disability or learning problems have been reported in about 10 percent of people with Townes-Brocks syndrome.

ORPHANET DEFINITION 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.

Inheritance

From: MedlinePlus Genetics, National Library of Medicine

Autosomal dominant

Frequency in the source

From: MedlinePlus Genetics, National Library of Medicine

Prevalence at birth: 1-9 / 1 000 000; Spain; Value and class.

Reported clinical features and what the terms mean

The following findings are associated with this condition in Orphanet. They are not a checklist for diagnosing yourself, and they do not all occur in every affected person. Some are examination, imaging or laboratory findings that cannot be recognised at home.

The frequency labels describe how often a finding was reported among people with the condition in the source. They do not give the chance that a person with that symptom has the condition. Definitions below reproduce HPO terminology; they explain the term, not the likely severity in an individual.

Abnormal pinna morphology · Very frequent (99-80%)

An abnormality of the pinna, which is also referred to as the auricle or external ear.

Anal atresia · Very frequent (99-80%)

Congenital absence of the anus, i.e., the opening at the bottom end of the intestinal tract.

Preauricular skin tag · Very frequent (99-80%)

A rudimentary tag of skin often containing ear tissue including a core of cartilage and located just anterior to the auricle (outer part of the ear).

Preaxial hand polydactyly · Very frequent (99-80%)

Supernumerary digits located at the radial side of the hand. Polydactyly (supernumerary digits) involving the thumb occurs in many distinct forms of high variability and severity. Ranging from fleshy nubbins over varying degrees of partial duplication/splitting to completely duplicated or even triplicated thumbs or preaxial (on the radial side of the hand) supernumerary digits.

Rectoperineal fistula · Very frequent (99-80%)

The presence of a fistula between the perineum and the rectum.

Rectovaginal fistula · Very frequent (99-80%)

The presence of a fistula between the vagina and the rectum.

Triphalangeal thumb · Very frequent (99-80%)

A thumb with three phalanges in a single, proximo-distal axis. Thus, this term applies if the thumb has an accessory phalanx, leading to a digit like appearance of the thumb.

Abnormal foot morphology · Frequent (79-30%)

An abnormality of the skeleton of foot.

Anteriorly placed anus · Frequent (79-30%)

Anterior malposition of the anus.

Clinodactyly of the 5th finger · Frequent (79-30%)

Clinodactyly refers to a bending or curvature of the fifth finger in the radial direction (i.e., towards the 4th finger).

Constipation · Frequent (79-30%)

Infrequent or difficult evacuation of feces.

Cryptorchidism · Frequent (79-30%)

Testis in inguinal canal. That is, absence of one or both testes from the scrotum owing to failure of the testis or testes to descend through the inguinal canal to the scrotum.

Hearing impairment · Frequent (79-30%)

A decreased magnitude of the sensory perception of sound.

Microtia · Frequent (79-30%)

Underdevelopment of the external ear.

Other findings in the same source

From: Orphanet

Additional reported features include Overfolded helix (Frequent (79-30%)); Pes planus (Frequent (79-30%)); Renal insufficiency (Frequent (79-30%)); Subcutaneous nodule (Frequent (79-30%)); Toe clinodactyly (Frequent (79-30%)); Abnormal cardiac septum morphology (Occasional (29-5%)); Abnormal cardiovascular system morphology (Occasional (29-5%)); Abnormal pulmonary valve morphology (Occasional (29-5%)); Abnormal renal morphology (Occasional (29-5%)); Abnormal rib morphology (Occasional (29-5%)). This is a selected summary, not a complete description of the condition.

When it may begin

From: MedlinePlus Genetics, National Library of Medicine

All ages

Inheritance in the source

From: MedlinePlus Genetics, National Library of Medicine

Autosomal dominant

Frequency and the population described

From: MedlinePlus Genetics, National Library of Medicine

Prevalence at birth: 1-9 / 1 000 000; Spain; Value and class.

Understanding the inheritance label

From: MedlinePlus Genetics

An autosomal dominant pattern means that one altered copy of a relevant gene can be sufficient for the condition. Some affected people inherit the change; others have a new change without an affected parent. The precise finding, family history and condition determine what this means for relatives.

Which doctor should you see?

The suggested department for discussing Townes-Brocks Syndrome is Clinical Genetics, with a clinical geneticist as the relevant type of clinician. Paediatrician (children) or physician (adults), with clinical geneticist referral.

This is an editorial referral starting point. The appropriate clinic depends on the person’s age, symptoms, previous diagnosis and local services. The first clinician can decide whether another specialty or a team is needed; a department label does not confirm the diagnosis.

How to prepare for an assessment

Bring a short timeline of the main symptoms: when they first appeared, whether they are constant or episodic, what seems to change them, and how they affect daily activities. Include previous reports, discharge summaries, current medicines and supplements, allergies, and any relevant family history. A dated record is more useful than trying to match every feature in an online article.

Ask the clinician what is already established and what remains uncertain. If a test is suggested, ask what question it answers, what its limitations are and how the result would change the next step. The information here is not an instruction to arrange every possible test. In children, bring growth, developmental and school information if it is relevant to the concern.

• Does the exact genetic or chromosome finding explain the observed features?
• Would a genetic counsellor help the family understand the result?
• Which organ-specific assessments are appropriate for this particular diagnosis?

Treatment discussions and follow-up

The material gathered for this draft does not provide a complete condition-specific treatment pathway for Townes-Brocks Syndrome. That gap does not mean that treatment is unavailable. A clinician needs to establish the diagnosis and review current guidance before recommending medicines, procedures, rehabilitation or other support.

Before leaving the appointment, clarify the next review date, who will communicate results, and whom to contact if the situation changes. Discuss difficulties with sleep, work, school, mobility, eating or emotional wellbeing when these are relevant. Practical support may require coordination between the treating clinician and other services.

The collected references do not establish a complete prevention or long-term outlook section for this entry. Missing information should not be interpreted as proof that prevention is impossible or that a particular outcome is inevitable. Ask what is known for the exact subtype, stage and personal circumstances, and which uncertainties remain.

When to seek emergency help

Severe breathing difficulty, collapse, new stroke-like symptoms, a seizure that is prolonged or repeated without recovery, uncontrolled major bleeding, or an immediate risk of self-harm require emergency help. In India, call 112 or reach the nearest emergency department. This is a general, non-exhaustive warning list; it is not a condition-specific triage tool.