TCF4 Expansion Genotyping
Genomic DNA was extracted from whole blood using conventional methodologies. A short tandem repeat (STR) assay was performed to genotype the CTG18.1 allele, in accordance with methods previously published by Wieben et al.9 In brief, genomic DNA was amplified using a 5′FAM conjugated primer (5′-CAGATGAGTTTGGTGTAAGAT-3′) and an unlabeled reverse primer (5′-ACAAGCAGAAAGGGGGCTGCAA-3′). Post PCR product separation was performed on the ABI 3730 Electrophoresis 96 capillary DNA analyzer (Applied Biosystems). Data analysis was performed using GeneMarker software (SoftGenetics).