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Townes-Brocks syndrome


Other Names for this Disease
  • Anus, imperforate, with hand, foot and ear anomalies
  • Deafness, sensorineural, with imperforate anus and hypoplastic thumbs
  • Imperforate anus with hand, foot and ear anomalies
  • Rare genetic disease
  • REAR syndrome
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Your Question

I am wondering about Townes-Brock syndrome because I was born with this condition and I don't know anything about it. Can you provide me with all the information that you have on Townes-Brock syndrome?

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What is Townes-Brocks syndrome?

Townes-Brocks syndrome is a genetic condition characterized by an obstruction of the anal opening (imperforate anus), abnormally shaped ears, and hand malformations that most often affect the thumbs. Most affected individuals have at least two of these three main features. The condition is caused by mutations in the SALL1 gene which provides instructions for making proteins that are involved in the formation of tissues and organs before birth. It follows an autosomal dominant pattern of inheritance.[1]
Last updated: 3/25/2015

What are the signs and symptoms of Townes-Brocks syndrome?

Townes-Brocks syndrome is characterized by an obstruction of the anal opening (imperforate anus), abnormally shaped ears, and hand malformations that most often affect the thumbs. Most people with this condition have at least two of these three major features.[1] Other possible signs and symptoms include kidney abnormalities, mild to profound sensorineural and/or conductive hearing loss, heart defects, and genital malformations. These features vary among affected individuals - even among those within the same family.[1][2] Intellectual disability or learning problems have also been reported in about 10 percent of people with Townes-Brocks syndrome.[1]

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Last updated: 3/25/2015

What causes Townes-Brocks syndrome?

Townes-Brocks syndrome is caused by mutations in the SALL1 gene. This gene is part of a group of genes called the SALL family. These genes provide instructions for making proteins that are involved in the formation of tissues and organs before birth. SALL proteins act as transcription factors, which means they attach (bind) to specific regions of DNA and help control the activity of particular genes. Some mutations in the SALL1 gene lead to the production of an abnormally short version of the SALL1 protein that malfunctions within the cell. Other mutations prevent one copy of the gene in each cell from making any protein. It is unclear how these genetic changes disrupt normal development and cause the  symptoms associated with Townes-Brocks syndrome.[1]
Last updated: 3/25/2015

How is Townes-Brocks syndrome diagnosed?

Townes-Brocks syndrome is diagnosed clinically based on the presence of the following:[2]
  • Imperforate anus
  • Abnormally shaped ears
  • Typical thumb malformations (preaxial polydactyly, triphalangeal thumbs which have three bones in them, much like the fingers, instead of the normal two, hypoplastic or underdeveloped thumbs) without shortening of the radius (the larger of the two bones in the forearm)

SALL1 is the only gene known to be associated with Townes-Brocks syndrome. Detection of a SALL1 mutation confirms the diagnosis. Genetic testing is available on a clinical basis.[2]

Last updated: 3/25/2015

Is Townes-Brocks syndrome genetic?

Yes. Townes-Brocks syndrome is inherited in an autosomal dominant fashion, which means that one copy of the altered gene in each cell is sufficient to cause the disorder. In about 50% of cases, an affected person inherits the mutation from an affected parent. The other 50% have the condition as a result of a new (de novo) mutation.[2][1]
Last updated: 3/25/2015

Is there treatment for Townes-Brocks syndrome?

Treatment is directed towards the specific symptoms, including immediate surgical intervention for imperforate anus; surgery for severe malformations of the hands; routine management of congenital heart defects; hemodialysis and possibly kidney transplantation for end-stage renal disease (ESRD); and early treatment of hearing loss. In addition, regular monitoring of renal function in individuals with and without renal anomalies is suggested.[2]
Last updated: 3/25/2015

What is the prognosis for individuals with Townes-Brocks syndrome?

The prognosis is variable, as the condition has quite a bit of variation in expression. The prognosis depends on the scope of symptoms seen in each individual patient. Generally, the disorder becomes life-threatening only in cases of severe cardiac and renal malformations.[3]
Last updated: 3/25/2015

References
Other Names for this Disease
  • Anus, imperforate, with hand, foot and ear anomalies
  • Deafness, sensorineural, with imperforate anus and hypoplastic thumbs
  • Imperforate anus with hand, foot and ear anomalies
  • Rare genetic disease
  • REAR syndrome
See Disclaimer regarding information on this site. Some links on this page may take you to organizations outside of the National Institutes of Health.