Diagnostic Tests for Mutations in the RB1 gene

The Solutions RB1 test uses a series of different molecular assays to identify the unique RB1 gene mutation of the proband, which includes these general steps:

Diagnosis of Unknown Mutations in the RB1 gene

• DNA is isolated from blood or retinoblastoma tumor.
  
  
• The size and copy number of each of the 27 exons and promoter region of the RB1 gene is determined by quantitative multiplex PCR.
  
  
• The DNA sequence is analyzed.
  
  
• In isolated cases of unilateral retinoblastoma, methylation-specific PCR is used to identify promoter hypermethylation.
  
  
• If other methods detect no mutation RT-PCR is used to search for intronic mutations likely to cause missplicing that leads to exon skipping.
  
  
• Results are confirmed and reported.
  
  

Testing Relatives for a Known Mutation

• DNA is isolated from a blood sample.
  
  
• One relatively simple test determines the presence or absence of the mutation found in the proband.