Broad Thumb-Hallux Syndrome; RSTS; RTS; Rubinstein Syndrome; Rubinstein-Taybi Deletion Syndrome

Rubinstein-Taybi Syndrome (RTS) is a rare genetic disorder with onset during early childhood. RTS affects multiple organ systems and is characterized by marked mental disability and physical abnormalities.

RTS has profound adverse effects on intellectual development in children, and is often accompanied by memory, mood, and anxiety disorders. The average IQ for individuals with RTS is about 50.

The most common type of RTS is caused by a mutation of the CREBBP gene on chromosome 16p13. A generally milder form of RTS is associated with mutations on the EP300 gene and accounts for approximately 3% of cases of RTS. In about 30-40% of cases, the exact cause is unknown.

Occasionally, microdeletion of chromosome 16p13.3 leads to failure to thrive and death in infancy. This extremely severe form is sometimes designated Rubinstein-Taybi Deletion Syndrome.

Diagnostic testing: Clinical diagnosis of RTS relies heavily on the combined presence of intellectual disability, broad thumbs and halluces (big toes), and unique facial features.

Genetic tests may confirm mutation, but are susceptible to false negatives.

Physical findings: Children with RTS are characterized by:

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  Abnormally broad thumbs and big toes;

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  Downward slanted eyelids;

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  Impaired vision;

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  Congenital heart defects;

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  Chronic gastrointestinal issues;

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  Prominent “beaked” nose;

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  Missing or misshapen teeth;

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  Small head;

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  High arched eyebrows;

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  Short stature; and

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  A high propensity for malignant and benign tumors.

ICD-9: 759.89

Children with RTS may appear to develop within normal ranges during prenatal and early infantile stages, but height, weight, and head circumference percentiles will rapidly decline in the first months of life.

When RTS presents in early childhood, individuals can be expected to achieve normal life expectancy.

Rubinstein-Taybi Deletion Syndrome presents in early infancy and is the most severe form. Survival past early childhood has not been observed in this subtype.

There is no specific treatment for RTS. Treatment is symptom-specific, to include:

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  Surgery to repair the bones in the thumbs or toes can sometimes improve grasp or relieve discomfort;

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  Early intervention programs and special education to address developmental disabilities;

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  Referral to behavioral specialists and support groups for family members;

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  Medical treatment for heart defects, hearing loss, and eye abnormalities; and

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  Medications to reduce the symptoms of constipation and gastroesophageal reflux disease (GERD).

Suggested MER for Evaluation:

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  Clinical history and examination that describes the diagnostic features of the impairment; and

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  Laboratory tests confirming mutation or deletion on chromosome 16p13.3.

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