EFCAB6 (EF-hand calcium binding domain 6) is a multifunctional protein with roles in androgen receptor signaling and ciliary function. In the nucleus, EFCAB6 negatively regulates androgen receptor activity by recruiting histone deacetylase complexes, though protein DJ-1 antagonizes this inhibition 1. In motile cilia, EFCAB6 functions as a microtubule inner protein component of dynein-decorated doublet microtubules essential for ciliary beating 2. The gene has emerged as a disease susceptibility locus in multiple conditions. GWAS analyses identified EFCAB6 among four genes shared between schizophrenia and body mass index, suggesting involvement in metabolic pathways relevant to schizophrenia pathophysiology 3. In hematologic malignancies, EFCAB6 disruption through chr22 translocation t(12;22) with HMGA2 may contribute to myeloproliferative neoplasm development, potentially through altered DJ-1 expression pathways 4. EFCAB6 variants have been associated with disorders of sex development and osteoporosis in premenopausal women, implicating the gene in reproductive hormone regulation and bone metabolism 5, 6. These diverse associations suggest EFCAB6 integrates calcium signaling with multiple physiological processes including hormonal responses, cilia function, and bone homeostasis.