An international team of scientists studying a rare genetic disease discovered that a bundle of proteins with the long-established function of keeping chromosomes together also plays an important role in regulating genes in humans.
When gene regulation is disrupted in the multisystem genetic disease Cornelia deLange syndrome (CdLS), children may suffer missing hands or fingers, mental retardation, growth failure, cleft palate, heart defects, and other impairments. For families and patients, better knowledge of how those genes perturb normal development may enable researchers to design better diagnostic tests for the disease, and also provide targets for eventual treatments.
The study appeared today in the online journal Public Library of Science Biology (PloS Biology). The study leader was Ian D. Krantz, M.D., a specialist in pediatric genetics at The Children's Hospital of Philadelphia, where he directs a unique full-service clinic for children with CdLS.
First described in 1933, CdLS affects multiple organs and typically results in distinctive facial features, such as thin eyebrows that join, long eyelashes, thin lips, and excessive body hair. It affects an estimated one in 10,000 children. In the past, CdLS was only recognized in its very severe form that was often fatal in childhood; now most children with the condition live into adulthood. CdLS has a wide range of severity, with the mildest form manifesting as apparent isolated mental retardation and/or autism.
Krantz and colleagues investigated cohesin, a protein complex consisting of at least four proteins that form a ring that encircles chromosomes during cell division. Cohesin's long-established role, called "canonical" by the authors, is to control chromatids-the long strands that chromosomes form when they copy their DNA.
However, said Krantz, one open question is biology has been, "What does cohesin do when cells are not dividing?" His team's paper provides part of the answer, as the first study in human cells to identify genes that are dysregulated when cohesin doesn't work properly. Cohesin's role in dysregulation of gene expression (regulating the degree to which specific genes are turned on or off) has attracted considerable scientific interest with a recent discovery that it may also be implicated in cancer.