Intelligence Disorders

Question 1

How are ID’s tested or investigated?

Answer 1

1. Assessing developmental milestones; comparing against average.
2. Psychometric (IQ) testing.
3. Imaging (CT/MRI)
4. Genetic sequencing (CGH/NGS)

Question 2

What does the IQ exam test?

Answer 2

1. Verbal intelligence.

2. Visuospatial intelligence

Question 3

What are the different classifications of intellectual disability in terms of IQ score?

Answer 3

ID occurs when IQ <70:

• Mild ID: 50-70
• Moderate ID: 36-50
• Severe ID: 20-35
• Profound ID: <20

Question 4

What is the major cause of severe ID?

Answer 4

Prenatal cause; genetic defects.

Question 5

What is the most common cause of ID?

Answer 5

Down Syndrome

Question 6

What is Fragile X Syndrome?

Answer 6

Abnormal synapse development caused by defect in Fragile X gene, presents as ID in males alongside dysmorphic features (large ears), epilepsy, visuspatial defects, and autism.

Question 7

Why are ID’s difficult to investigate? Why is the research slow and difficult to progress?

Answer 7

• Most IDs do not have a reported “syndrome”
• In many cases the gene is unknown.
• Genetic defect manifestations are different than what was previously reported, causing doubt and confusion.

Question 8

What is Rett Syndrome?

Answer 8

Common ID in girls, appears as:

• Apraxia (inability to perform movements on demand)
• Breathing problems.
• Dysfunctional gait.
• Microcephaly.
• Hand movement dysfunction.

Question 9

What is Rett Syndrome caused by?

Answer 9

MeCP2 mutations.

Question 10

What is MeCP2?

Answer 10

Protein that regulates the expression of genes in response to environmental changes (epigenetics) by methylating promotor sites.

Question 11

How are new syndromes discovered?

Answer 11

Through genome-wide testing in patients with ID.

Question 12

What is the process of treatment development from start to finish?

Answer 12

1. Gene discovery.
2. Animal model trials, identify target candidates.
3. Open label trial
4. Clinical trial to validate targets.