Question

A 10 month old child presents with weakness, coarse facial features, and a normal ECG. What is the likely diagnosis?

• A. Hurler syndrome
• B. Hunter syndrome
• C. Glycogen storage disorder
• D. Phenylketonuria

Hint:

Hurler syndrome damages the heart early with an abnormal ECG; Hunter syndrome is milder, so a normal ECG favours Hunter.

Answer 1

The Correct Option is B

Step 1: Recognise the group of disease.
Weakness with coarse facial features in an infant points toward a storage disorder, most likely one of the mucopolysaccharidoses, a group of inherited diseases where the body cannot break down long sugar chains called glycosaminoglycans, so they pile up in tissues and cause coarse features, joint stiffness, and slowed development.

Step 2: Compare the two main types in the options.
Hurler syndrome and Hunter syndrome both cause coarse facial features, joint stiffness, and mental retardation, so on looks alone they can be hard to tell apart.

Step 3: Use the heart finding to separate them.
Hurler syndrome damages the heart valves and heart muscle badly, causing a clearly abnormal ECG and heart failure, and untreated children usually die from these cardiovascular complications by around 6 to 10 years of age. Hunter syndrome also affects the heart, but far more gently, and a normal ECG in a 10 month old fits a milder, slower disease course.

Step 4: Rule out the other options.
Glycogen storage disorders such as Pompe disease cause weakness with cardiomegaly and a markedly abnormal ECG from the earliest infancy, this does not match a normal ECG. Phenylketonuria causes developmental delay and a musty body odour, but it does not cause coarse facial features or joint stiffness, and it is picked up on newborn screening for raised phenylalanine, not by cardiac findings.

Step 5: Note the inheritance pattern.
Hunter syndrome is inherited in an X-linked recessive pattern and largely affects boys, and it generally runs a milder overall course than Hurler syndrome, including less severe heart and eye involvement.

Final Answer:
A normal ECG in a child with coarse features and weakness points away from Hurler syndrome and toward the milder Hunter syndrome.