This gene encodes a member of the basic helix-loop-helix leucine zipper family, and can function as a cellular transcription factor. The encoded protein can activate transcription through pyrimidine-rich initiator (Inr) elements and E-box motifs. This gene has been linked to familial combined hyperlipidemia (FCHL). Alternative splicing of this gene results in multiple transcript variants. A related pseudogene has been defined on chromosome 21.,USF1,FCHL,FCHL1,HYPLIP1,MLTF,MLTFI,UEF,bHLHb11,Epigenetics & Nuclear Signaling,Transcription Factors,Cancer,Endocrine & Metabolism,Lipid Metabolism,Endocrine and metabolic diseases,Diabetes,Cardiovascular,Hypoxia,Heart,Cardiovascular diseases,Heart disease,USF1