Hunter Syndrome Information for Healthcare Providers

These photographs are representative of one patient only. Signs and symptoms are unique to each patient and age at progression may vary.

You may be seeing Hunter syndrome before anyone else.

Hunter syndrome (Mucopolysaccharidosis II, MPS II) is a serious progressive genetic disorder that affects boys almost exclusively¹. It is caused by a deficiency or absence of the lysosomal enzyme iduronate-2-sulfatase (I2S). This enzyme is required for the degradation of specific glycosaminoglycans (GAG); thus its absence results in a harmful accumulation of these substances in cells throughout the body^2,3.

Symptoms generally appear between the ages of 2 and 4 years, and can vary widely among patients¹. Hunter syndrome can show up first as recurrent otitis media¹, chronic rhinorrhea³, or enlarged tonsils and adenoids⁴ — conditions common in many children. But when your patient returns with recurrent infection, look for a cluster of signs and symptoms that might also include^1,3,5:

• Coarse facial features, including depressed nasal bridge, thick nostrils and lips, and enlarged tongue
• Large head (macrocephaly)
• Possible CNS involvement frequently including delayed development
• Joints of fingers, arms, and legs held in partial flexion
• Conductive or sensorineural deafness, otitis media
• Airway obstruction, enlarged adenoids or tonsils, sleep apnea
• Abnormal heart valves
• Umbilical or inguinal hernia
• Enlarged abdomen (due to enlarged liver and spleen)
• Short stature, dysplasia, and joint stiffness

Photos 2 and 3 provided courtesy of Joseph Muenzer, MD, PhD, Chapel Hill, NC

Screening and diagnosis

A urine test can be used to quickly screen for potential Hunter syndrome, and a definitive diagnosis can be made by a medical geneticist using a simple blood test that identifies the enzyme deficiency of Hunter syndrome (lack of iduronate-2-sulfatase).

You can find out more about Hunter syndrome including screening and diagnosis information at Genetest.org

Click here to find specific labs that do testing for Hunter syndrome.

Refer appropriate patients to a medical geneticist immediately for a definitive diagnosis. Faster diagnosis means faster disease management.

If you are an Otolaryngologist and would like more information, click here.

References:

1. Neufeld EF, Muenzer J. The mucopolysaccharidoses. In: Scriver CR, Beaudet AI, Sly WS, et al, eds. The Metabolic and Molecular Bases of Inherited Disease. 8th ed. New York, NY: McGraw-Hill; 2001:3421-3452.
2. Fenton CL, Rogers W. Mucopolysaccharidosis type II. eMedicine Journal [serial online]. 2006. www.emedicine.com. Accessed April 3, 2006.
3. Finlayson LA. Hunter syndrome (mucopolysaccharidosis II). Pediatr Dermatol. 1990;7(2):150-152.
4. Institute of Neurological Disorders and Stroke. National Institutes of Health. Mucopolysaccharidoses fact sheet. www.ninds.nih.gov. Accessed January 8, 2008.
5. Wilcox WR. Lysosomal storage disorders: the need for better pediatric recognition and comprehensive care. J Pediatr. 2004;144(suppl):S3-S14.