Huntington diseases

Question 1

What is a Neurogenerative disorder?

Answer 1

Progressive loss of neuronal function and/or neuronal cell death

Question 2

True or False

Neurodegenerative disorders all involve molecular abnormalities.

The molecular mechanism for cell death is a matter of intense investigation and debate

Answer 2

True

Question 3

For the inheritance of Huntington’s disease,

in almost all cases, an affected individual has (affected/unaffected) parent

No Sex linkage

Answer 3

affected

Question 4

True or False

Huntington’s disease (H.D.) is manifest in adulthood

H.D. is progressive, It has no singular point of onset, and it worsens over time.

The earliest symptoms usually involve impairments to motor control

It is a terminal disease

Answer 4

True

Question 5

_____-is a neurological disorder that results in abnormal involuntary movements.

First prominent indication of H.D. and often a key factor for diagnosis

Answer 5

Chorea

Question 6

What is the first major indicator of H.D. increasing slowly over time?

What resulting in problems controlling movement begins later and increases more quickly over time?

What progresses steadily throughout the disorder?

Answer 6

Chorea

Motor impairement

Dementia

Question 7

The progression of H.D. can be classified into stages. What are the stages before diagnosis and what is the stage after the diagnosis?

Answer 7

Before diagnosis

Premanifest, presymptomatic, prodromal based on motor signs and symptoms

After diagnosis

Manifest

Question 8

What is the central dogma of molecular biology?

Hint: Bis 101

Answer 8

DNA stores information about protein structure through genetic instructions

DNA can be copied into identical replicas to allow this information to be preserved in all cells after cell division

Question 9

How is H.D. caused?

Answer 9

CAUSED BY AN AUTOSOMAL DOMINANT ALLELE FOR THE HUNTINGTIN GENE (H.G.)

H.G. is on the short arm of Chr. 4

The H.G. has a CAG nucleotide repeat near its beginning

The CAG codon corresponds to the amino acid glutamine

Question 10

What are the CAG repeats for unaffected and affected individuals?

FYI Penetrance refers to the proportion of individuals with a particular genotype who will develop an associated phenotype

Answer 10

Unaffected

Normal: 26 or less … no disease

Intermediate: 27-35 do not develop symptoms but their children are at risk for developing H.D.

Affected

Reduced penetrance: 36-39 : May or may not develop symptoms at any age, many develop symptoms in old age

Full penetrance 40 or more : have disease

Question 11

True or False

H.D. results in enlargement of the size of the verticles

The most prominent neurodegeneration occurs in the striatum (caudate “CN’ and putamen”)

Answer 11

True

Question 12

True or False

Loss of function, mutations result in a reduction in the normal function of a protein encoded by that gene, is the primary cause of Huntington’s neurodegeneration.

Answer 12

False

it is not the primary cause

Question 13

H.D. is associated with visible aggregates of protein inside neurons called __________

Contain PolyQ portion of Huntington proteins

Answer 13

Inclusions

Question 14

True or False

Inclusions are thought to cause cell death.

Answer 14

False

Instead, they seem to protect the cell, perhaps by requesting otherwise harmful abnormal Huntingtin protein.

Question 15

True or False

The brain’s striatum is particularly vulnerable to degeneration caused by Huntington’s.

Specific neuronal cell types in the striatum are more vulnerable than other

Answer 15

True

Question 16

Define and describe the importance of striatum

Answer 16

The striatum is a cluster of neurons within the basal ganglia, a subcortical part of the cerebrum.

The striatum consists of the caudate nueclus and the putamen.

The striatum is important to control voluntary movements, action planning, decision making, learning, reward processing, and motivation.