FARSA encodes the alpha subunit of cytoplasmic phenylalanyl-tRNA synthetase (FARS1), which forms a heterotetramer with two FARSB beta subunits to catalyze phenylalanine-tRNA aminoacylation essential for protein biosynthesis 1. The enzyme transfers phenylalanine to tRNAPhe through magnesium-dependent ATP hydrolysis, with key residues like R475 involved in phenylalanine activation and transfer 2. Biallelic pathogenic variants in FARSA cause a multisystemic disorder characterized by interstitial lung disease, brain abnormalities with calcifications, liver dysfunction, growth restriction, and facial dysmorphism 13. Patients may also present with inflammatory profiles, autoimmunity, and systemic inflammatory syndrome 4. Disease-causing variants either disrupt heterotetramer formation or reduce enzymatic activity, with some variants showing complete loss of catalytic function 2. FARSA exhibits non-canonical functions beyond aminoacylation, including cell cycle regulation through PI3K-AKT and FOXO1-RAG1 pathways 5, and competition with Notch signaling via its N-terminal domain 6. The protein can be functionally inhibited by C9orf72-associated repeat RNA, leading to reduced phenylalanine incorporation in proteins 7. Clinically, FARSA deficiency represents a severe, often fatal condition requiring supportive care and potential JAK inhibition for inflammatory complications 4.