Mucopolysaccharidosis: Model Clinical Case and Viva Q&A

Clinical Case of Mucopolysaccharidosis in Children

Clinical Case: Mucopolysaccharidosis Type II (Hunter Syndrome)

A 4-year-old boy, Alex, is brought to the pediatric clinic by his parents with concerns about his developmental delays and frequent respiratory infections. His parents report the following:

• Coarse facial features that have become more pronounced over the past year
• Delayed speech development and difficulty understanding simple instructions
• Recurrent upper respiratory tract infections (6 episodes in the last 12 months)
• Enlarged liver and spleen noticed during a recent well-child visit
• Stiff joints, especially in the hands, limiting fine motor skills
• Umbilical and inguinal hernias repaired at age 2

Physical examination reveals:

• Height and weight below the 3rd percentile for age
• Coarse facies with a broad nose, thick lips, and enlarged tongue
• Macrocephaly (head circumference above 97th percentile)
• Hepatosplenomegaly
• Limited range of motion in multiple joints
• Mild hearing loss detected during audiometry

Initial investigations:

• Skeletal survey: Dysostosis multiplex, including J-shaped sella turcica and paddle-shaped ribs
• Echocardiogram: Mild mitral and aortic valve thickening
• Urinary glycosaminoglycans (GAGs): Elevated, predominantly dermatan sulfate

Based on the clinical presentation and initial findings, mucopolysaccharidosis type II (Hunter syndrome) is suspected. Enzymatic assay confirms deficiency of iduronate-2-sulfatase, establishing the diagnosis. Genetic testing reveals a pathogenic variant in the IDS gene, confirming X-linked inheritance.

Management plan includes multidisciplinary care, enzyme replacement therapy with idursulfase, and genetic counseling for the family.

Clinical Presentations of Mucopolysaccharidosis in Children

Varieties of Clinical Presentations of Mucopolysaccharidosis in Children

1. MPS I (Hurler, Hurler-Scheie, and Scheie syndromes)

   • Coarse facial features, macrocephaly
   • Progressive cognitive decline (in Hurler syndrome)
   • Corneal clouding, retinal degeneration
   • Recurrent upper respiratory infections, obstructive sleep apnea
   • Hepatosplenomegaly, umbilical and inguinal hernias
   • Joint stiffness and contractures
   • Cardiac valve abnormalities
   • Dysostosis multiplex (skeletal deformities)

2. MPS II (Hunter syndrome)

   • Coarse facial features, macrocephaly
   • Behavioral problems and developmental regression (in severe form)
   • Hearing loss
   • Recurrent respiratory infections, airway obstruction
   • Hepatosplenomegaly
   • Joint stiffness and contractures
   • Carpal tunnel syndrome
   • Cardiac valve disease and cardiomyopathy

3. MPS III (Sanfilippo syndrome)

   • Mild coarsening of facial features
   • Severe behavioral problems (hyperactivity, aggression)
   • Progressive cognitive decline and developmental regression
   • Sleep disturbances
   • Seizures
   • Mild skeletal abnormalities
   • Hearing loss

4. MPS IV (Morquio syndrome)

   • Short stature with disproportionate trunk
   • Skeletal dysplasia (genu valgum, kyphoscoliosis)
   • Joint laxity
   • Odontoid hypoplasia with atlantoaxial instability
   • Corneal clouding
   • Preserved intellect
   • Cardiac valve abnormalities

5. MPS VI (Maroteaux-Lamy syndrome)

   • Coarse facial features
   • Short stature
   • Corneal clouding
   • Hepatosplenomegaly
   • Joint stiffness and contractures
   • Cardiac valve disease
   • Spinal cord compression
   • Normal intelligence

6. MPS VII (Sly syndrome)

   • Coarse facial features
   • Hydrops fetalis in severe cases
   • Hepatosplenomegaly
   • Short stature
   • Joint stiffness
   • Cardiac abnormalities
   • Variable cognitive impairment

7. MPS IX (Hyaluronidase deficiency)

   • Soft tissue masses
   • Short stature
   • Mild coarsening of facial features
   • Joint pain and swelling
   • Normal intelligence

Knowledge Check: Question and Answers for Medical Students & Professionals

This interactive quiz component covers essential viva questions and answers. It includes 30 high-yield viva questions with detailed answers.

Question 1 of 30

Disclaimer

The notes provided on Pediatime are generated from online resources and AI sources and have been carefully checked for accuracy. However, these notes are not intended to replace standard textbooks. They are designed to serve as a quick review and revision tool for medical students and professionals, and to aid in theory exam preparation. For comprehensive learning, please refer to recommended textbooks and guidelines.