NUDT15 p.R139C variant is common and strongly associated with azathioprine-induced early leukopenia and severe alopecia in Korean patients with various neurological diseases

The NUDT15 p.R139C variant had a strong association with azathioprine induced leukopenia in Korean patients with various neurological diseases. Patients with the T/T genotype had a lower white blood cell count than those with the C/T or C/C genotype (454 ± 118.65 vs. 1860 ± 1650.12 vs. 2264.58 ± 479.61, respectively). In addition, the interval from the onset of azathioprine therapy to leukopenia tended to be shorter in mutant homozygous (T/T) patients compared with those carrying the C/T or C/C genotype (33.6 ± 22.30 vs. 251.66 ± 313.75 vs. 347.75 ± 298.65, respectively).22