BCAS4 (Breast Carcinoma Amplified Sequence 4) is a Protein Coding gene. Diseases associated with BCAS4 include choanal atresia. An important paralog of this gene is BLOC1S4. BCAS4 A chromosomal aberration involving BCAS4 has been found in some breast carcinoma cell lines. Translocation t(17;20)(q23;q13) with BCAS3. Belongs to the cappuccino family. 3 isoforms of the human protein are produced by alternative splicing.