Hunter Syndrome and Bullʼs Eye Maculopathy

Mucopolysaccharidoses (MPSs) refer to a heterogeneous group of lysosomal storage disorders affecting the breakdown of glycosaminoglycans (GAGs), polysaccharide compounds involved in cell signaling and other biochemical processes [1]. The diseases, caused by genetic defects, result in multiorgan intra- and extracellular accumulation of the mentioned GAGs [2]. MPSs are classified into 7 types and 13 subtypes. MPS type II, also called Hunter syndrome, is an X-linked recessive disease with a deficiency in the lysosomal enzyme Iduronate-2-sulphatase, resulting in pathological storage of dermatan and heparan sulphate. Clinically, most organ systems are affected to a certain degree [3]. Cardiological and respiratory failure are the most common cause of death, which occurs at adolescence in severe forms [4].