SLCO1B1*41 is assigned no function based on strong evidence. SLCO1B1*41 is defined by c.481+1G>T which disrupts a canonical splice site. An individual genotyped SLCO1B1*31/*41 exhibited an elevated plasma concentration of coproporphyrin I, at a level comparable to that in SLCO1B1*15/*15 patients (39511784). Individuals compound heterozygous for *41 experienced statin-induced rhabdomyolysis (34887219, 39511784). SLCO1B1*41 was significantly associated with altered hexadecanedioate and SLCO1B1-associated oxylipins levels in individuals with *41 vs those without (27602404, 39644095). A large clinical study demonstrated that individuals with SLCO1B1*41 exhibited significantly increased bilirubin levels relative to those without, however there was no significant association with statin-induced myotoxicity (40047317). Additionally, SLCO1B1 loss-of-function has been implicated in the pathogenesis of Rotor syndrome and SLCO1B1*41 has been identified in affected families (22232210). The variant effect predictors CADD and PhD-SNPg predict that c.481+1G>T impairs protein function, which is supported by a published in silico analysis (35631530). Expression of a truncated protein due to aberrant splicing is also supported by SpliceAI predictions.