FLAD1 encodes flavin adenine dinucleotide synthetase 1, an enzyme essential for riboflavin metabolism and FAD homeostasis. The protein exhibits dual enzymatic activities: FAD synthase activity that catalyzes the adenylation of flavin mononucleotide (FMN) to form FAD coenzyme, and FAD diphosphatase activity that hydrolyzes FAD to FMN 1. Beyond its catalytic functions, FLAD1 facilitates the delivery of FAD to client apo-flavoproteins and its enzymatic balance may be regulated by redox-sensing cysteine residues 1. The enzyme is crucial for cellular bioenergetics, redox homeostasis, DNA repair, and chr1 remodeling through its role in flavocoenzyme biosynthesis 1. Biallelic FLAD1 mutations cause FAD synthase deficiency, leading to lipid storage myopathy with multiple acyl-CoA dehydrogenation deficiency (MADD), which responds to riboflavin supplementation 21. FLAD1 expression is increased in various cancers, including breast cancer and hepatocellular carcinoma, where it promotes tumor progression through metabolic reprogramming 34. In triple-negative breast cancer, FLAD1 amplification enhances FAD-dependent lysine demethylase 1 activity, promoting lipid biosynthesis pathways crucial for cancer progression 3.