SMC1A (structural maintenance of chromosomes protein 1A) forms part of the cohesion multiprotein complex that is necessary for sister chromatid cohesion and proper chromosome segregation during cell division. SMC1A and the cohesion complex are also involved in forebrain development and loss or inherited mutation of SMC1A results in holoprosencephaly. SMC1A mutations are also associated with Cornelia de Lange syndrome, a genetic development disorder described by varied features that include cognitive disability with autistic features, premature aging, and delayed development, among others. In immunohistochemistry, SMC1A has nuclear positivity in most tissues throughout the body. References: Human Molecular Genetics. 2018. 27(17):3002–3011, DOI:10.1093/hmg/ddy203; Brain. 2019 Jul 23. pii: awz210. doi: 10.1093/brain/awz210