Oligonucleotide Expansion Syndromes

Question 1

this inheritance is due to homologous regions at the tips of X and Y chromosomes where recombination can occur

Answer 1

pseudoautosomal inheritance

Question 2

mutation in SHOX gene***
dominantly inherited
females mostly

Answer 2

Leri Weill Dyschondrosteosis

Question 3

short stature*
mesomelic shortening of distal limbs*

Answer 3

Leri Weill Dyschondrosteosis

Question 4

male-limited precocious puberty
father to son transmission

Answer 4

sex limited AD inheritance

Question 5

father to son transmission
deletion in AZF region on Y chromosome 11

Answer 5

Y chromosome infertility

Question 6

azoospermia (no mature sperm)
oligospermia (low sperm count)
abnormal sperm

Answer 6

Y chromosome infertility

Question 7

mutation in SRY
46, XY (affects females)

Answer 7

Swyer Syndrome

Question 8

female external genitalia
gonadectomy to prevent gonadoblastoma
hormone replacement therapy to induce menstruation

Answer 8

Swyer Syndrome

Question 9

mutation in mt-ND6

Answer 9

Leber’s hereditary optic neuropathy (LHON)

Question 10

degeneration of retinal ganglion cells
loss of central vision***
reduced penetrance in females

Answer 10

Leber’s hereditary optic neuropathy

Question 11

mutation in mt-TL1

Answer 11

MELAS

Question 12

myopathy
mitochondrial encephalomyopathy
lactic acidosis
stroke like sx’s

Answer 12

MELAS

Question 13

as disease moves through generations, it manifests earlier with each generation

Answer 13

anticipation

Question 14

CAG repeat in HTT gene
anticipation

Answer 14

Huntington’s Disease

Question 15

chorea- uncontrollable jerky movements**
triad of sx’s:
motor
cognitive
psychiatric

Answer 15

Huntington’s disease

Question 16

CGG repeat in FMR1 gene
unstable mutation
anticipation

Answer 16

Fragile X (reduced penetrance in females)

Question 17

difference b/t Fragile X and down syndrome

Answer 17

fragile X will be inherited, down syndrome won’t be

Question 18

x-linked dominant
intellectual disability
long face, prominent jaw and forehead, large ears, macro-orchidism

Answer 18

Fragile X

Question 19

CTG repeat of DM1 protein kinase (DM1 is a spliceopathy)
autosomal dominant

Answer 19

Myotonic muscular dystrophy

Question 20

muscle weakness*
cataracts*
myotonia***
“warm up phenomenon”
myopathic face

Answer 20

Myotonic muscular dystrophy

Question 21

GAA repeats on FXN; iron handling
gene silencing
autosomal recessive

Answer 21

Friedreich ataxia

Question 22

ataxia**
loss of sensation in extremities**
impaired speech**
scoliosis
cardiomyopathy-main cause of death**

Answer 22

Friedreich ataxia