Mutations occur in the Ig Smu region but rarely in Sgamma regions prior to class switch recombination.
Schrader CE, Bradley SP, Vardo J, Mochegova SN, Flanagan E, Stavnezer J. Mutations occur in the Ig Smu region but rarely in Sgamma regions prior to class switch recombination. EMBO J. 2003 Nov 03; 22(21):5893-903.