Hunter syndrome, also known as mucopolysaccharidosis II, is part of a family of lysosomal storage diseases in which a deficiency in the specific lysosomal enzymes causes accumulation of glycosaminoglycans. In Hunter syndrome, there is a deficiency in iduronate-2-sulfatase (I2S), which catalyzes the removal of the sulfate group at the 2 position of L-iduronic acid in dermatan sulfate and heparan sulfate.1Patients become symptomatic as these glycosaminoglycan compounds accumulate in lysosomes throughout the body. Characteristic symptoms include growth delay, distinct abnormal facies, joint stiffness, cardiomyopathy, and neurologic and pulmonary dysfunction. An otolaryngologist may also be consulted to evaluate recurrent otitis media, chronic rhinorrhea, and enlarged adenoids and tonsils, which can cause obstructive sleep apnea, as these diagnoses are more common in patients with Hunter Syndrome.
Radiology Quiz Case 1: Diagnosis. Arch Otolaryngol Head Neck Surg. 2010;136(1):97. doi:10.1001/archoto.2009.182-b