Rubinstein-Taybi syndrome (RSTS) is a rare genetic condition. People with RSTS often have distinctive facial features, broad thumbs, and moderate to severe intellectual disability.

Symptoms of RSTS can vary from person to person. Some people may experience more severe symptoms, while others have milder symptoms. Symptoms often begin before birth or in the first 4 weeks of life. Medical professionals often recognize RSTS at birth or in infancy because of the condition’s characteristic facial features and effects on the hands and feet.

In this article, we will discuss what RSTS is, including its causes, symptoms, treatment options, and more.

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RSTS, which doctors also refer to as broad thumb-hallux syndrome, is a genetic condition that typically causes intellectual disability and a number of physical symptoms. Infants with RSTS often have typical prenatal growth. However, in the first few months of life, they exhibit rapid decreases in the following physical markers:

  • height percentile
  • weight percentile
  • head circumference percentile

RSTS is a very rare condition, affecting approximately 1 in 100,000—125,000 newborns. The name of the condition derives from Dr. Jack Rubinstein and Dr. Hooshang Taybi, who identified it as a recognizable syndrome in 1963.

RSTS is a genetic condition that occurs as a result of a change in the DNA sequence.

RSTS may result from a change in the CREBBP gene, which is the most common gene that medical professionals associate with RSTS. Changes in the CREBBP gene are present in 50–60% of people with RSTS.

This gene provides instructions for the CREBBP binding protein, which helps regulate the activity of many genes throughout the body. Evidence suggests that this protein plays an important role in controlling cell growth and division and appears to have a critical role in brain development and the formation of long-term memories.

Alternatively, RSTS may result from a change in the EP300 gene, though this is less common. Changes in the EP300 gene are present in roughly 3–8% of people with RSTS. This gene is responsible for making a protein called p300, which is involved in cell growth and division and appears to play a critical role in development.

Another possible cause of RSTS is a deletion, which is a very small loss of genetic material. In people with RSTS, the deletion occurs on the short (p) arm of chromosome 16. This region of chromosome 16 includes the CREBBP gene, which is why this deletion may result in RSTS.

However, the loss of additional genes may account for other complications of the condition.

Most cases of RSTS result from a new (de novo) genetic change. This means that the variation is not present in either of the infant’s parents. In this case, a parent has less than a 1% chance of having a second infant with RSTS.

In rare cases, an infant can inherit RSTS from a parent in an autosomal dominant pattern. If a person has RSTS, then their children have a 50% chance of inheriting it.

Other evidence highlights the potential role of epigenetics in the development of the condition. Epigenetics examines how certain chemical compounds and proteins can attach to DNA and direct actions such as turning genes on or off and controlling the production of proteins. These compounds do not change the DNA sequence but instead change the ways cells use the DNA’s instructions.

RSTS symptoms and their severity can vary from person to person. Below are some of the symptoms that are often present in people with the condition.

Intellectual disability

Intellectual disability is a common symptom of RSTS. This symptom often originates during development. Intellectual disability in people with RSTS is often moderate to severe, but it can vary from person to person.

Behavioral symptoms

The following behavioral characteristics are common in individuals with RSTS:

  • repetitive behaviors
  • challenging behaviors
  • aggressive behaviors
  • temper outbursts
  • self-injurious behaviors
  • attention difficulties
  • mental health difficulties
  • autism characteristics
  • heightened sociability

Characteristic head and facial features

Several symptoms relating to the head and face often occur in people with RSTS. Common facial and head features include:

  • downward-slanting eyes
  • a low-hanging nasal septum
  • a high palate
  • long eyelashes
  • high-arched eyebrows
  • talon cusps, which are extra cusps on the inner side of front teeth

Other potential complications

Broad and often angular thumbs and big toes are common features in people with RSTS. Short stature is also common and often presents in adulthood.

Additionally, the following complications may occur:

  • Eye problems: People with RSTS often have eye problems, including:
    • refractory errors
    • drooped eyelids
    • cataracts
    • glaucoma
    • strabismus, in which the eyes point in different directions
    • involuntary eye movements
    • corneal problems
  • Congenital heart abnormalities: Approximately one-third of people with RSTS have some form of congenital heart condition.
  • Kidney issues: Kidney problems and urinary tract infections are common in people with RSTS.
  • Dental issues: People with RSTS may have a variety of dental issues, including:
    • crowding of teeth
    • misaligned teeth
    • tooth infections
    • hypodontia, or missing teeth
    • hyperdontia, which causes too many teeth to grow
    • talon cusps
  • Hearing issues: Hearing loss is common in people with RSTS and is often due to recurrent or refractory middle ear disease.
  • Obesity: Many adults with RSTS develop obesity.

A medical professional may make an initial diagnosis of RSTS based on the visible clinical features. They may look out for:

  • downward-slanting eyes
  • a low-hanging nasal septum
  • a high palate
  • talon cusps on the front teeth
  • broad and angular thumbs and big toes

A doctor may then use certain tests to help confirm their diagnosis. An X-ray may reveal problems in the bones in the hands and feet. These problems may be characteristic of RSTS and can help a doctor make a diagnosis.

Doctors may also use genetic testing to confirm their diagnosis. During genetic testing, a medical professional will take a blood or saliva sample and examine it for changes in the person’s DNA. If a person has changes in the CREBBP gene or the EP300 gene, a doctor may be able to diagnose RSTS.

Treatment options for RSTS aim to support people in their daily lives and manage certain symptoms. Treatment may include:

  • Physical therapy: Physical therapy can help treat certain physical symptoms of RSTS, such as skeletal problems.
  • Orthopedic surgery: A doctor may suggest that a person with RSTS undergo orthopedic surgery to help correct issues in the hands and feet.
  • Speech therapy: Speech therapy may help a child with RSTS improve the way they communicate with those around them.

A person with RSTS may also benefit from the following treatments to help them carry out daily tasks and gain independence:

  • vocational training
  • behavioral therapy
  • special education programs

An infant with RSTS may need early intervention to help prevent or monitor respiratory and feeding difficulties.

Symptoms of RSTS vary from person to person. A person with RSTS will often undergo yearly evaluations to:

  • monitor eye health
  • monitor hearing ability
  • look out for cardiac problems
  • look out for dental issues
  • look out for renal problems

People living with RSTS may experience several complications throughout life, including:

  • eye issues
  • hearing loss
  • respiratory issues
  • heart abnormalities
  • feeding issues

Research shows that more than 90% of people with RSTS reach adulthood.

RSTS is a rare genetic condition that affects approximately 1 in 100,000–125,000 newborns. It often causes intellectual disability and characteristic physical symptoms, such as broad and angular thumbs and big toes, downward-slanting eyes, and a low-hanging nasal septum

Symptoms often begin before birth or in the first 4 weeks of life. Physical therapy and surgery may help address some of the physical symptoms of RSTS. People may also benefit from speech therapy and behavioral therapy to help them gain independence and improve their communication with others.