with a 2.8- and 2.4-fold reduction in response to mitogen and antigen, respectively, compared to controls. Analysis of CD4 and CD8 T-cell subset proliferation after T-cell receptor (see TCR, 186880) stimulation demonstrated that patient cells divided up to 3 times whereas control cells divided up to 5 times. Gorska and Alam (2012) concluded that the UNC119 G22V mutation impairs LCK-dependent T-cell function.