Repeat Expansion Conditions

Question 1

What is the inheritance pattern of Myotonic Dystrophy Type 2?

Repeat Expansion Disorder

Answer 1

Autosomal Dominant

Question 2

What is the inheritance pattern of Fragile X Syndrome?

Trinucleotide Repeat Expansion Disorder

CGG

Answer 2

X-linked

Gene = FMR1

Question 3

FMR1 premutation disorders

Can effect males and females

Not everyone with a premutation will develop these disorders.

Answer 3

• FXPOI: premature ovarian insufficiencyo and annorhea (20% risk for female carriers)
• FXTAS: Fragile X-associated tremor/ataxia syndrome: late-onset, progressive cerebellar ataxia and intention tremor. Loss of short-term memory, executive function and cognition, parkinsonism, peripheral neuropathy, lower limb proximal muscle weakness, and autonomic dysfunction. Age and dependent with increasing incidence over time.
• FXAND: Fragile X–Associated Neuropsychiatric Disorders (50% of premutation carriers)

Question 4

Amytrophic Lateral Sclerosis (ALS)/Frontotemporal Dementia (FTD)

Repeat Expansion Disorder

Answer 4

Autosomal Dominant

Question 5

What is the inheritance pattern of Fredreich Ataxia?

Answer 5

Autosomal Recessive