Hearing Loss Associated with Metabolic Disorders

Question 1

What are mucopolysacchroidoses (MPS)?

Answer 1

A group of lysosomal storage diseases caused by various enzyme deficiencies that catalyze the breakdown of mucopolysaccharides

Question 2

What are mucopolysaccharides?

Answer 2

Long chains of sugar molecules

Question 3

How many MPS’s are there?

Answer 3

7

Question 4

Do all MPS’s have a chronic progressive course?

Answer 4

Yes

Question 5

What transmission does MPS have?

Answer 5

All are AR, except for Hunter syndrome (x-linked)

Question 6

What type of hearing loss is associated with MPS?

Answer 6

All forms show a conductive loss caused by upper respiratory tract infections and otitis media
Many have SNHL
Auditory brainstem is also abnormal

Question 7

How is MPS managed?

Answer 7

PE tubes
Hearing aids

Question 8

What is MPS-1H?

Answer 8

Hurler syndrome
Most severe form

Question 9

How is hurler syndrome recognized?

Answer 9

During infancy when patients are abnormally large

Question 10

What other characteristics does hurler syndrome have?

Answer 10

Coarse facial features
Macroglossia (large tongue) and corneal clouding
Characteristic skeletal deformities
Dysostosis multiplex (skeletal abnormalities) & joint contractures
Recurrent otitis media and hearing loss
Intellectual disability
Cardiac failure may occur prior to diagnosis
Despite intervention, death by ~ 10 years

Question 11

What is MPS - II?

Answer 11

Hunter syndrome
Mild to severe

Question 12

What transmission does hunter syndrome have?

Answer 12

X-linked

Question 13

What is the severe form of hunter syndrome?

Answer 13

MPS IIA

Question 14

Is the severe form of hunter syndrome more common?

Answer 14

Yes

Question 15

What are some characteristics of MPS IIA?

Answer 15

Rapid intellectual deterioration
Progression of dysostosis multiplex
Coarsening of features similar to Hurler’s syndrome
Abdominal hernia with protruding abdomen & chronic diarrhea
Death between 10 to 15 years of age

Question 16

What is the mild form of hunter syndrome?

Answer 16

MPS IIB

Question 17

Is MPS IIB survivable to adulthood?

Answer 17

Yes

Question 18

Is hearing loss common in both the mild and severe form of hunter syndrome?

Answer 18

Yes

Question 19

What is the transmission of a biotinidase deficiency?

Answer 19

AR

Question 20

What is a biotinidase deficiency?

Answer 20

Deficiency of biotin
Biotin is essential for the activity of many enzyme systems
In this disorder, biotin is not released from proteins in the diet during digestion

Question 21

Is biotinidase deficiency treatable and preventable?

Answer 21

Yes with biotin supplements

Question 22

What are some signs and symptoms of biotinidase deficiency?

Answer 22

Seizures
Hypertonia and ataxia
Developmental delay
Skin rash
Optic atrophy
Deafness
SNHL and visual impairment are not reversible once they develop