Etiology and pathogenesis of the cohesinopathies

Cohesin is a chromosome-associated protein complex that plays many important roles in chromosome function. Genetic screens in yeast originally identified cohesin as a key regulator of chromosome segregation. Subsequently, work by various groups has identified cohesin as critical for additional processes such as DNA damage repair, insulator function, gene regulation, and chromosome condensation. Mutations in the genes encoding cohesin and its accessory factors result in a group of developmental and intellectual impairment diseases termed 'cohesinopathies.' How mutations in cohesin genes cause disease is not well understood as precocious chromosome segregation is not a common feature in cells derived from patients with these syndromes. In this review, the latest findings concerning cohesin's function in the organization of chromosome structure and gene regulation are discussed. We propose that the cohesinopathies are caused by changes in gene expression that can negatively impact translation. The similarities and differences between cohesinopathies and ribosomopathies, diseases caused by defects in ribosome biogenesis, are discussed. The contribution of cohesin and its accessory proteins to gene expression programs that support translation suggests that cohesin provides a means of coupling chromosome structure with the translational output of cells.