SUMMARY

 

1.  Rubinstein-Taybi syndrome is characterized by the following clinical features:

 

-Broad thumbs and great toes
-Characteristic facial features
-Short stature
-Developmental delay
-Cardiac abnormalities
-Increased susceptibility to infections

 

2.  Immunologic abnormalities reported in patients include T cell lymphopenia, thymic hypoplasia, impaired delayed cutaneous hypersensitivity response, and impaired specific antibody response.  

 

3.  Microdeletions and truncating mutations in the CREB-binding protein (CBP) gene are found in approximately 40-60% of patients.  Mutations in the EP300 gene have been reported in a small number of patients. 

 

4.  Patients with specific antibody deficiency may benefit from prophylactic antibiotic therapy or immunoglobulin replacement therapy. 

 

 

 

 

OVERVIEW

 

 

     Rubinstein-Taybi syndrome is characterized by the following clinical features:

 

-Broad thumbs and great toes
-Characteristic facial features
-Short stature
-Developmental delay
-Cardiac abnormalities
-Increased susceptibility to infections

 

     Immunologic abnormalities reported in patients include T cell lymphopenia, thymic hypoplasia, impaired delayed cutaneous hypersensitivity response, and impaired polysaccharide antibody response.  

 

     Microdeletions and truncating mutations in the CREB-binding protein (CBP) gene are found in approximately 40-60% of patients.  Mutations in the EP300 gene have been reported in a small number of patients. 

 

 

                                 

EVALUATION

 

Step 1:  Immune Evaluation

 

-IgG, IgM, IgA, 
-Specific antibody responses to vaccine antigens
-Lymphocyte subset enumeration by flow cytometry (CD3, CD4, CD8, CD19, CD16/56)
-In vitro T cell proliferation to Mitogens

 

-Immunoglobulin levels are typically normal

-Responses to both protein antigens (tetanus and diphtheria) as well as polysaccharide antigens (pneumovax) should be evaluated.  Impaired specific antibody responses have been reported in patients.

-T cell lymphopenia has been reported in patients.

-Decreased T cell function may be present. 

 

Step 2:  Gene Sequencing

 

-CREBBP gene sequencing

 

-Genetic testing for CREBBP mutations is commercially available at a number of testing sites (ex. Gene Dx). However it should be noted that mutations in this gene are only found in 40-60% of cases.  

 

 

 

 

MANAGEMENT

     
    Patients with specific antibody deficiency may benefit from prophylactic antibiotic therapy or immunoglobulin replacement therapy.