MERTK and retinal disorder: However, our findings are consistent with observations from the previous genetic study, where interestingly, whilst there was no structural difference in MERTK mRNA transcripts amongst two Swedish Vallhund retinopathy cases from Finland (neuro-retina and RPE) and an unaffected dog of a different breed, an analysis of MERTK expression levels demonstrated a 6.5-fold increased level of MERTK expression in four Vallhund cases when compared to two controls of other breeds [25].