Rubinstein-Taybi syndrome

Rubinstein-Taybi syndrome

Definition:

A genetic disease characterized by mental deficiency, broad thumbs and toes, short stature, and characteristic facial features.

Alternative Names:

Rubinstein syndrome

Causes, incidence, and risk factors:

Rubinstein-Taybi syndrome is a rare condition, affecting about 1 in 125,000 people. The proof of this disease being genetic was shown by discovery of mutations in, or loss of, a gene (CREBB) on chromosome 16 that rarely is inherited in an autosomal dominant manner. However, most cases are not inherited, rather they are sporadic and likely due to a new mutation affecting the patient, but not his or her parents. The classic finding is broad thumbs and great toes, but the condition is manifested by many other findings including: short stature, a peculiar face, low-set ears, port-wine-stain, undescended testicles in the male, and downward slant of the eyes.

Symptoms:

broad thumbs and great toes
slow development of both cognitive and motor skills with low muscle tone
mental retardation
short stature that develops after birth
palpebral slant - eye slants downward
pinna abnormalities and low set ears
excess hair on body (hirsutism)
thick and arched eyebrows with long eyelashes
narrow, small, or recessed mouth with crowded teeth
prominent or 'beaked' nose

Signs and tests:

decreased IQ in range of 30-80
hypoplastic maxilla (small jaw), narrow palate, crowded teeth
an unsteady or stiff walking gait
low-set ears or malformed ears
ptosis (drooping eyelid)
cataract
coloboma (a defect in the iris of the eye)
cryptorchidism or other testicular problems
macrocephaly (excessively large head) or microcephaly (excessively small head)
skeletal (limb) abnormalities including the last segment of the other fingers/toes appearing broad on x-rays or physical examination
genetic testing, including deletion testing to see if the CREBB gene is missing or mutation testing

Treatment:

There is no specific treatment for Rubinstein-Taybi syndrome. Symptoms such as mental retardation are treated as necessary with speech and cognitive therapy. Treatment may not be necessary in all cases.

Support Groups:

Rubinstein-Taybi Parents Group USA 1-888-447-2989

Expectations (prognosis):

The majority of children can learn to read at an elementary level. The majority have delayed motor development, but average age to learn to walk is by 2 1/2 years of age.

Complications:

Complications vary depending on the symptoms that are present. Feeding difficulties are common in infancy. Recurrent ear infections with hearing loss can result. Surgical repair of thumbs or great toes can sometimes improve grasp or relieve discomfort. Both abnormal heart structures at birth and abnormal heart rhythms have been reported. There is an increased risk for keloid formation of the skin.

Calling your health care provider:

Call for an appointment with your health care provider if you child does not seem to be developing normally. An appointment with a geneticist is appropriate if the provider finds signs of Rubinstein-Taybi syndrome such as broad thumbs and toes.

Prevention:

There is no known prevention for this rare disorder. Prenatal genetic testing may be available if the affected parent has a known mutation.

Review Date: 9/13/2001
Reviewed By: David G. Brooks, M.D., Ph.D., Division of Medical Genetics, University of Pennsylvania Medical Center, Philadelphia, PA. Review provided by VeriMed Healthcare Network.

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