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Health library/Mucopolysaccharidosis type II

Rare metabolic disorders / RARE CONDITION

Mucopolysaccharidosis type II

Also known as: Hunter syndrome, I2S deficiency, Iduronate 2-sulfatase deficiency, MPS II

Mucopolysaccharidosis type II is an inherited storage disorder also called Hunter syndrome. It usually affects boys and can progressively involve airways, joints, organs and development.

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What you may notice

Symptoms can overlap with other conditions and vary between people.

  • Joint stiffness
  • Enlarged liver or spleen
  • Hearing difficulties
  • Developmental or airway problems

Understanding care

Clinical care may include metabolic specialist assessment and individualized organ, sensory and developmental monitoring. A qualified clinician decides which investigations and options fit the individual situation.

When to seek help

Arrange specialist assessment for growth, feeding or developmental concerns. Breathing difficulty, loss of responsiveness or new seizures requires urgent care rather than a community review.

For severe breathing difficulty, collapse, suspected stroke, or another emergency, call local emergency services immediately. In India, call 112.

Read the medical sources

These sources support the educational article and offer more detail.

Educational reading · Updated 6 October 2026

Prepared from the linked sources. This summary has not had an independent clinician review. A qualified clinician can assess symptoms and explain which information applies to you.

A child and a caring grown-up reading a picture book together

LITTLE PEOPLE. BIG FEELINGS.

It’s okay to have
a lot of questions.

A doctor visit or an unfamiliar health word can feel scary. You can ask a trusted grown-up to help you understand, one small question at a time.

01

Say how you feel.

“I feel worried” is a good place to start.

02

Ask for simple words.

“Can you explain that in a way I understand?”

03

Bring someone you trust.

A caring adult can help you ask and listen.

For children and their grown-ups. This illustration explains a conversation, not a diagnosis. An adult should seek qualified care for a child who is unwell.

Mucopolysaccharidosis type II — First AID health library