TSPAN10 and Strabismus: Notably, the lead variant at the strabismus locus, rs75078292, is in very tight LD (r2 = 0.98) with non-synonymous variant rs6420484, which introduces a tyrosine residue in place of an evolutionarily conserved cysteine at position 177 of TSPAN10, the gene encoding tetraspanin-10 (Online Resource 4).