Also known as RTS, Rubinstein-Taybi Syndrome is a multi-system genetic condition distinguished by abnormalities of the face, broad thumbs, and broad toes. Developmental disabilities are also present in those with RTS.
The known history of this disorder dates back to 1957, when it was first described. In 1963, it was described again by Dr. Jack Ribinstein and Dr. Hooshang Taybi, at which point it was finally recognized as an identifiable syndrome.
Rubinstein-Taybi Syndrome Symptoms
The symptoms of Rubinstein-Taybi Syndrome can be broken down into two categories: ocular and nonocular.
Ocular symptoms include:
- Downward-slanting eyes
- Eyes that are widely spaced (also known as misaligned eyes)
- Droopy eyelid (or ptosis)
- Eyebrows that are highly arched
- Frequent eye infections (often due to tear duct blockage)
Rarely, congenital glaucoma, larger-than-average eyes, and cloudy corneas can also occur.
There are several nonocular symptoms that can occur with RTS. Not all symptoms will be present in each patient, though.
- Thumbs and toes that are broader than normal
- Mental developmental delays from mild to severe
- A nose that appears beaked
- Delayed bone progression resulting in a short stature
- A broad nasal bridge
- Ears that are deformed
- High arched palate
- A nose that has an extra fold of skin on either side
- Microcephaly (a small head)
- A lower jaw that is smaller than normal
- A forehead with a flat red birthmark
- Joints that are hyperextensible
- A pelvis that is small and tilted
- Excessive hair growth
- Undescended testicles
- Difficulties feeding
- Infections of the respiratory tract
- Cardiac anomalies
- Vertebral abnormalities
- GERD (gastroesophageal reflux and vomiting)
- Abnormalities of the kidney
- Problems with orthopedics
Cognitive Delays in RTS
Children with RTS have differing degrees of cognitive delays when compared to non-RTS children. Most of the time, these delays are evaluated when a child reaches school age. They are then recognized as having an intellectual disability. Individuals with RTS may possess certain limits in their intellectual functions, such as the ability to reason, learn, and solve problems.
Physical and Motor Delays in RTS
Many children with RTS will experience developmental delays in their physical and motor skills. This is often the result of low muscle tone. These delays, coupled with cognitive delays, often result in difficulties with balance and motor control. This can result in developmental delays in rolling over, sitting up, feeding, walking, and general self-care.
Communication Delays in RTS
In cases of RTS, it is common for children to experience significant delays in their development of speech. In fact, this is the case for more than 90% of children with RTS. Difficulty eating can be an early sign of a possible delay in speech. This is because coordination of the mouth and tongue is necessary both when eating and speaking.
How Is Rubinstein-Taybi Syndrome Diagnosed?
Diagnosis with RTS is usually based on clinical or physical features. Oftentimes, a downward slant of the eyes is present. Other factors that help diagnose RTS include a low-hanging nasal septum, a high palate, teeth that appear cusp-like, and broad thumbs and toes.
To further support a diagnosis of RTS, x-ray studies may be conducted to look for abnormalities in bones, especially in the hands and feet. Other scans may be used to observe electrical activity present in the brain.
Additionally, genetic testing might be able to confirm the presence of RTS chromosome mutations. It should be noted, though, that not all patients will carry this mutation. Most diagnoses are done at childbirth, while other children are not diagnosed until later. This depends on the severity of their condition.
Rubinstein-Taybi Syndrome Behavior Problems
Behavioral problems are often present in children with RTS and are regarded as the main aspect relating to the quality of life of these individuals. Common behavioral problems include:
These behaviors seem to change with age, however.
What Causes Rubinstein-Taybi Syndrome?
The most common cause of RTS is the development of a new genetic mutation that typically isn’t carried by the parents. For parents who have no genetic markers for RTS but have a child who is born with this new gene mutation, the chance of having a second child with RTS is less than 1%.
It is possible for a child to inherit an autosomal dominant pattern from their parents. This means that if a parent has RTS, then their children have a 50% chance of inheriting the gene responsible for this condition.
The CREBBP gene is the most common gene accountable for the development of RTS. Up to 60% of individuals with RTS have some variant of the CREBBP gene.
Up to 8% of those with RTS have mutations in the EP300 gene.
RTS is known to affect all genders equally. While the exact number of RTS cases is unknown, research from the Netherlands has been conducted that it could be anywhere between one in 100,000 or one in 125,000.
Rubinstein-Taybi Syndrome Treatment
The treatment of RTS depends on the symptoms of the affected individual. Managing this condition may require efforts from a team of specialists that include pediatricians, cardiologists, orthopedists, audiologists, urologists, nephrologists, and more.
An RTS-specific growth chart should be utilized to keep an eye on the child’s growth rate. In addition, annual eye exams and hearing evaluations should be conducted, as well as long-term monitoring of cardiac, renal, and dental anomalies.
If there are skeletal anomalies present, then orthopedic surgery, supportive techniques, and physical therapy may be used to help treat these anomalies. Surgery may also be required on the hands or feet if fingers or toes are misaligned.
Early intervention is critical for some affected people. This can help prevent and monitor any respiratory or feeding difficulties related to RTS. Other treatment plans include special education programs, behavioral therapies, speech therapies, and vocational training to ensure adequate development of the affected individual.
Finally, it is recommended that affected individuals and their families receive genetic counseling.
There are some clinical trials available for people with RTS. To find out more information regarding these trials, you can contact your local government, visit www.clinicaltrials.gov, or contact the NIH Patient Recruitment Office.