BRD1 and premenstrual tension: This suggests the presence of other genes on chromosome 22 that contribute to the stereotypical PMS phenotype, likely candidates being SULT4A1 and BRD1. Additionally, individuals with PMS with 22q13 deletions larger than 6–8 Mb are also at risk of developing gastrointestinal problems since their deletion is large enough to include PNPLA3, and the loss of both PNPLA3 and CYP2D6 have been implicated in reducing a patient’s ability to metabolize various pharmaceuticals.