Primers were designed using Primer347 (link),48 (link). PCR was performed using GOTaq polymerase (Promega, Madison, WI, USA) on DNA from peripheral blood and on cDNA from lymphoblastoid cells, using standard protocol. Capillary electrophoresis sequencing (ABI 3130 genetic analyzer; Applied Biosystems, Carlsbad, CA, USA) was performed using the ABI BigDye terminator V3.1 Cycle Sequencing Kit (Applied Biosystems, Carlsbad, CA, USA), following standard protocol. Data was analysed in CLC DNA Workbench (CLC Bio, Aarhus, Denmark).