Hunter syndrome is a rare, inherited disease in which the sugar molecules (mucopolysaccharides) are
not broken down correctly and build up in the body. The condition is caused by a lack
of enzyme iduronate sulfatase. The early-onset (severe) form of Hunter syndrome begins
shortly after age 2. The symptoms include: aggressive behavior, hyperactivity, mental
function decline, severe intellectual disability and spasticity. Other symptoms may
include: carpal tunnel syndrome, coarse facial features, deafness, hairy body (hypertrichosis),
joint stiffness and a large head (macrocephaly). Individuals with this disorder may
experience the following signs: abnormal retina, heart murmur and leaky heart valves,
enlarged liver (hepatomegaly) enlarged spleen (splenomegaly), inguinal hernia, and
TESTING, PHYSICAL FINDINGS, AND ICD-9-CM CODING
Definitive diagnostic lab testing: Enzyme studies documenting absent or deficient
levels of iduronate-2-sulfatase (I2S). Genetic testing for change (mutation) in the
iduronate sulfatase gene, and urine testing for heparan sulfate and dermatan sulfate.
Pulmonary function testing, echocardiogram, EMG/NCS (nerve conduction studies), CT
scan/ MRI may be supportive. Slit lamp examination.
Physical Findings: Coarse facial features, thickened skin, narrowing of the cervical
spinal canal (spinal stenosis), short stature, enlarged tongue (macroglossia) and
vocal cords, enlarged liver and spleen, retinal degeneration, contractures of the
joints, leaky heart valves, umbilical or inguinal hernia, carpal tunnel syndrome,
buildup of cerebrospinal fluid in the brain (hydrocephalus) and enlarged head (macrocephaly).
ICD-9: 277.5 Mucopolysaccharidosis
Suggested MER for Evaluation: Enzyme assay for iduronate sulfatase; evidence of progressive neuro-developmental
delay; physical examination of the eyes, heart, liver, spleen, respiratory, neurologic
and musculoskeletal systems.