Zhang Y, et al. - Given that functional variants in catechol-O-methyltransferase (COMT) gene contribute to variability in pain perception, researchers here searched for their impact on pain perception in African American sickle cell disease (SCD) patients. In this work, two risk single-nucleotide polymorphisms (SNPs) (rs4633 and rs165599) and the corresponding haplotype (ATCAA) in women were observed to be associated with increased frequency of pain-related emergency room visit. Hence suggesting that in women, COMT functional variants could predispose SCD patients to worse acute pain.