Hunter Syndrome Flashcards
A 4-year-old boy is brought to the clinic due to behavioral changes and developmental delay. The parents note that he has been more hyperactive recently and seems to have difficulty learning new skills. On examination, the child has coarse facial features, hepatosplenomegaly, joint contractures, and a hoarse voice. His vision appears intact, with no evidence of corneal clouding. Genetic testing confirms an X-linked inheritance pattern. Which of the following is the most likely diagnosis?
A) Hurler Syndrome
B) Hunter Syndrome
C) Fabry Disease
D) Niemann-Pick Disease
E) Tay-Sachs Disease
Answer: Hunter Syndrome
Explanation: Hunter Syndrome (Mucopolysaccharidosis type II) is an X-linked recessive lysosomal storage disorder caused by a deficiency of iduronate-2-sulfatase, leading to the accumulation of dermatan sulfate and heparan sulfate. Clinical features include coarse facial features, hepatosplenomegaly, joint contractures, and developmental delay. Unlike Hurler Syndrome, Hunter Syndrome does not cause corneal clouding, and the inheritance pattern is X-linked.
Incorrect Answers:
A) Hurler Syndrome presents similarly but is autosomal recessive and includes corneal clouding.
C) Fabry disease causes neuropathic pain, angiokeratomas, and renal or cardiac involvement but does not involve coarse facial features or hepatosplenomegaly.
D) Niemann-Pick disease presents with hepatosplenomegaly and neurodegeneration but lacks coarse facial features and skeletal abnormalities.
E) Tay-Sachs disease presents with neurodegeneration and a cherry-red macula but no hepatosplenomegaly or coarse features.
What is Hunter Syndrome?
Hunter Syndrome is a rare genetic disorder caused by the deficiency of the enzyme iduronate-2-sulfatase.
True or False: Hunter Syndrome affects both males and females equally.
False, it primarily affects males.
What type of inheritance pattern does Hunter Syndrome follow?
X-linked recessive inheritance pattern.
What is the primary cause of Hunter Syndrome?
The primary cause is a mutation in the IDS gene, leading to enzyme deficiency.
What is the role of iduronate-2-sulfatase in the body?
Iduronate-2-sulfatase helps break down glycosaminoglycans (GAGs) in the body.
Is Hunter Syndrome a form of mucopolysaccharidosis?
Yes, Hunter Syndrome is classified as mucopolysaccharidosis type II (MPS II).
True or False: Hunter Syndrome is inherited in an autosomal dominant manner.
False, Hunter Syndrome is inherited in an X-linked recessive manner.
At what age do symptoms of Hunter Syndrome typically begin to appear?
Symptoms usually appear between ages 2 and 4.
Fill in the blank: Children with Hunter Syndrome may have _____ facial features.
coarse
What are common symptoms of Hunter Syndrome?
Common symptoms include:
- Coarse facial features, “Gargoylism.”
- Skeletal abnormalities (Dysostosis multiplex)
- Short stature
- Developmental delays
- Hepatosplenomegaly
- Cardiac issues
Fill in the blank: Hunter Syndrome primarily affects _____ individuals.
male
Multiple choice: Which of the following is NOT a symptom of Hunter Syndrome? A) Hearing loss B) Hyperactivity C) Joint stiffness D) Cloudy corneas
B) Hyperactivity (ADHD)
True or False: Hunter Syndrome can be treated with enzyme replacement therapy.
True, enzyme replacement therapy is a treatment option for Hunter Syndrome.
What are potential complications of Hunter Syndrome?
Complications can include heart disease, airway obstruction, and cognitive impairment.
- obstructive sleep apnea can be evaluated with polysomnography.
