Syndecan-1 (NP_001006947.1) is a widely expressed cell surface heparan sulfate proteoglycan whose molecular cloning as ‘syndecan’ (Saunders et al, ’89), later known as syndecan-1, was the springboard for the discovery of syndecans-2 through -4. Expression in the eye has been documented in corneal, limbal (GDS2433) and conjunctival epithelial cells, meibomian (GDS1361) and lacrimal (NEIBank) glands, and in retina and retinal pigmented epithelium/choroid (NEIBank). The syndecan-1 gene ‘SDC1’ consists of five exons extending over 24.6 kb in human chromosome 2. Ensembl release 57 lists thirty-four orthologues ranging from sea squirt to human. After cleavage of the signal peptide, syndecan-1 in humans is 288 amino acids long with a theoretical molecular weight and pI respectively of 30 kDa and 4.5. Migration in SDS PAGE however appears as a high molecular weight smear because glycosylation is extensive with substitution by as many as three heparan sulfate and two chondroitin sulfate glycosaminoglycans (Fig. 1). Heparan sulfate polymerization is initiated on serines 37 (15* [*after signal peptide cleavage]), 45 (23*) and 47 (25*) within the respective amino terminal core protein sequences DGSGD and NFSGSGA. Chondroitin sulfate can be substituted on serines 207 (185*; EGSGE) and 217 (195*; ETSGE) in proximity with the ectodomain cleavage site RKE and the adjacent transmembrane domain. One N-linked glycosylation site is predicted on asparagine 43 (22*; NFSG; NetNGlyc 1.0). NetOGlyc 3.1 reveals 33 potential sites of O-glycosylation most between between amino acids 68 (46*) and 180 (158*) (Fig. 1). The human core protein sequence is subject to some variation with four known nonsynonymous single nucleotide polymorphisms: proline 19 to leucine within the signal peptide, threonine 75 (53*) to methionine, leucine 136 (114*) to glutamine, and glycine 259 (237*) to valine (Fig. 1). Variation is also introduced at the level of alternative splicing. Variant transcripts code for mature core proteins of 169, 215 and 288 amino acids, the latter translated as the wild type