A research team, based at the University of Valladolid in Spain, has proposed using gene expression levels of an ocular surface protein as a diagnostic marker for the diagnosis of dry eye syndrome (DES). The research, published in the journal of Investigative Ophthalmology & Visual Science (2011, Vol. 52, No.11, pp8363-8369) reports on a retrospective study conducted between 2000-2009 on almost 70 patients with dry eye syndrome. Expression levels of several mucins – high molecular weight proteins found on the ocular surface – showed significantly lower levels of activity in patients with DES compare to age and sex-matched control subjects. In particular, the MUC1 gene, demonstrated the greatest sensitivity (83.3%) and specificity (87.5%) among all of the mucins tested. The finding may be used to develop a valuable clinical tool for both diagnosis and clinical trial endpoints.