Charcot Marie Tooth DLA

Question 1

What is the role of Peripheral Myelin Protein?

Answer 1

Role of Peripheral Myelin Protein (PMP-22)
Secreted by Schwann Cells
Essential for layering Schwann cell membrane as myelin

Mutation in PMP-22

Severe hypomyelination Clumsy, Tremor, Muscle atrophy

A Mutation in PMP2 Causes Dominant Demyelinating Charcot-Marie-Tooth Neuropathy

Single AA substitution (Gly by Asp)

Limb weakness due to muscle atrophy. Gross and fine motor movements: Not fatal

Question 2

Describe. Charcot-Marie-Tooth disease

Answer 2

→dysfunctional PMP-22 gene
→hereditary motor and sensory neuropathy (HMSN)
most common inherited neurological disorders
Symptoms and Signs usually develop during adolescence

Are due to the chronic degeneration Of peripheral nerves leading to clumsiness initially and eventually into a plethora of serious sign

Question 3

Describe synapse retraction and elimination

Answer 3

Mononeural Innervation (MI) in Humans is achieved
by synapse elimination

MI Optimizes the control of force; Adult forms of channels
& receptors

NGF taken by retrograde axonal transport

“Competition between the inputs results in progressive changes in synaptic structure and strength, and the “loser” eventually retracts its terminal ending and the branch that gives rise to it”

Question 4

Describe synapse elimination

Answer 4

Apoptosis
Between 40-75% neurons made, will die after migration – death is normal and necessary
Neurons die due to failure to compete for chemicals provided by targ

Polyneural skeletal motor end plate when embryonic but mononeural post natal