Rubinstein-Taybi syndrome Health Article

Definition

Rubinstein-Taybi syndrome is a genetic disease characterized by broad thumbs and toes, short stature, distinctive facial features, and varying degreess of mental retardation.

Alternative Names

Rubinstein syndrome

Causes, incidence, and risk factors

Rubinstein-Taybi syndrome is a rare condition, affecting about 1 in 125,000 people. Most persons with RTS have a defect in a gene that leads to an abnormal CREB binding protein (CREBBP).

About 10% of patients, typically with more severe problems, are missing the gene entirely and do not make any CREBBP.

Most cases are sporadic and likely due to a new mutation occurring during fetal development, which was not passed on by either parent. However, in some cases, it is inherited in an autosomal dominant fashion, which means that if one parent passes on the defective gene, the child will be affected.

Symptoms

• Broadening of the thumbs and big toes
• Constipation
• Excess hair on body (hirsutism)
• Heart defects possibly requiring surgery (about 30% of patients)
• Mental retardation
• Seizures
• Short stature that is noticeable after birth
• Slow development of cognitive skills
• Slow development of motor skills accompanied by low muscle tone

Signs and tests

Examination and testing may reveal:

• An underdeveloped bone in the midface
• Narrow palate
• Crowded teeth
• Unsteady or stiff walking gait
• Downward-slanted eyes
• Low-set ears or malformed ears
• Drooping eyelid (ptosis)
• Cataracts
• 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 and toes, appearing broad on x-rays or physical examination
• Thick and arched eyebrows with long eyelashes
• Narrow, small, or recessed mouth with crowded teeth
• Prominent or "beaked" nose
• Absent or extra kidney, and other problems with kidney or bladder

Genetic tests can be done to determine if the CREBBP gene is missing.

Treatment

There is no specific treatment for Rubinstein-Taybi syndrome. Symptoms such as mental retardation are treated as necessary with speech and cognitive therapy. Surgical repair of thumbs or great toes can sometimes improve grasp or relieve discomfort. Treatment may not be necessary in all cases.