TSBP1 (testis expressed basic protein 1) is a nuclear protein located on chromosome 6 within the MHC region whose function remains incompletely characterized, though genetic evidence suggests involvement in immune-mediated diseases. TSBP1 and its associated long non-coding RNA (TSBP1-AS1) have been identified as genetic risk factors across multiple autoimmune and developmental conditions. In childhood-onset systemic lupus erythematosus (cSLE), a chromosome 6 SNP intronic to TSBP1-AS1 (rs9268469) showed genome-wide significant association (OR 2.04, P = 1.79 × 10⁻⁸) 1. TSBP1-AS1 variants were also associated with pemphigus susceptibility, with differential expression patterns observed in blood mononuclear cells and keratinocytes, suggesting roles in autoimmune responses 2. Genetic variants in TSBP1 show associations with positive antinuclear antibody tests (rs1967688, P = 4.84 × 10⁻⁸) 3 and appear in shared genetic loci between celiac disease and neuropsychiatric disorders 4. Additionally, TSBP1 variants associate with rheumatoid arthritis in sex-stratified analyses 5, asthma susceptibility in Kazakh populations (rs3132954, P = 1.33 × 10⁻¹²) 6, and orofacial cleft development 7. TSBP1 also shows hemoglobin concentration associations in European populations 8. These findings suggest TSBP1 participates in immune regulation and craniofacial development, though mechanistic details require further investigation.