PDC and glaucoma: Of interest, but not thought to be directly involved in the development and onset of SjS, is the presence of genes specific to the ocular/lacrimal gland etiology (for example, Pdc [phosducin], which is a protein of the retinal photoreceptors cells [33], and Myoc [myocilin], whose product interacts with olfactemedin involved in glaucoma [34]).