What is Rubinstein-Taybi Syndrome

Rubinstein-Taybi syndrome (RSTS) is a rare genetic condition characterized by distinctive facial features, broad thumbs and big toes, and varying degrees of intellectual disability. It is caused by mutations in specific genes involved in cell growth and development, most commonly the CREBBP or EP300 genes, and typically occurs sporadically rather than being inherited from parents.

What are the primary characteristics of Rubinstein-Taybi syndrome?

Individuals with Rubinstein-Taybi syndrome often present with a recognizable physical profile, though the severity of symptoms varies significantly from person to person. The hallmark clinical features include broad, sometimes angulated thumbs and great toes, which are present at birth in nearly all cases. Facial features associated with Rubinstein-Taybi syndrome include a high arched palate, a beaked nose, downward-slanting eyes, and long eyelashes. Beyond physical appearance, the condition affects multiple body systems, often resulting in developmental delays, intellectual disability, and challenges with growth and feeding during infancy.

Which body systems are affected by Rubinstein-Taybi syndrome?

Because Rubinstein-Taybi syndrome involves genes that regulate gene expression throughout the body, the condition is multisystemic. Common clinical findings include:

• Skeletal System: Broad thumbs and broad toes are the clinical signature, often accompanied by short stature and sometimes scoliosis.


• Neurological Development: Moderate to severe intellectual disability is common, as are delays in speech and motor skill acquisition.


• Cardiac and Renal Systems: Approximately 30-40% of patients may have congenital heart defects, and a smaller percentage experience kidney or urinary tract abnormalities.


• Gastrointestinal: Many infants with Rubinstein-Taybi syndrome experience severe feeding difficulties, gastroesophageal reflux, and chronic constipation.

How common is Rubinstein-Taybi syndrome and who does it affect?

Rubinstein-Taybi syndrome is quite rare, with an estimated prevalence ranging from 1 in 100,000 to 1 in 125,000 live births. It affects both males and females equally and has been documented in diverse populations worldwide, with no known geographical or ethnic predilection. In the vast majority of cases, Rubinstein-Taybi syndrome occurs as a de novo (new) mutation in the individual, meaning it is not inherited from either parent. Currently, 232 people with Rubinstein-Taybi syndrome have joined the DiseaseMaps community, sharing their experiences to help others navigate life with this diagnosis.

What causes Rubinstein-Taybi syndrome at the genetic level?

The underlying mechanism of Rubinstein-Taybi syndrome involves the loss of function of genes responsible for chromatin remodeling, which is essentially the "packaging" of DNA. When the CREBBP gene (located on chromosome 16) or the EP300 gene (on chromosome 22) is mutated or deleted, the body cannot produce enough of the proteins necessary for normal cell development. This disruption affects how genes are turned on and off during critical stages of growth, leading to the developmental and physical patterns observed in the syndrome.

Next steps

• Consult a clinical geneticist to confirm the diagnosis through molecular genetic testing.


• Schedule multidisciplinary evaluations, including cardiac, renal, and ophthalmological screenings.


• Connect with the DiseaseMaps community to share experiences and find support from families navigating similar challenges.


• Engage with early intervention programs, including physical, occupational, and speech therapy, to maximize developmental potential.

Medical disclaimer: This information is for educational purposes only and should not replace professional medical advice, diagnosis, or treatment; always consult with a qualified healthcare provider regarding your specific health needs.

References

• National Institutes of Health (NIH) Genetic and Rare Diseases Information Center (GARD): Rubinstein-Taybi Syndrome Overview.


• Orphanet: Portal for rare diseases and orphan drugs, entry on Rubinstein-Taybi syndrome.


• Online Mendelian Inheritance in Man (OMIM): Database entry #180849 (CREBBP) and #613684 (EP300).


• Rubinstein-Taybi Syndrome Foundation: Patient-focused resources and clinical research updates.