X-linked diseases

Question 1

What are the clinical manifestations of Lesch-Nyhan Syndrome?

Answer 1

neuro and behavioral abnormalities; overproduction of uric acid; self injury

Question 1

What is the fitness of Duchenne Muscular Dystrophy?

Answer 1

0%

Question 2

What is the incidence rate of Lesch-Nyhan Syndrome?

Answer 2

1:380,000

Question 2

What is not made in Duchenne Muscular Dystrophy?

Answer 2

dystrophin

Question 3

What is the gene mutation in Lesch-Nyhan Syndrome? Why does uric acid build up?

Answer 3

HPRT1; purines are recycled

Question 4

What is the incidence rate for Rett Syndrome?

Answer 4

1:10,000 females (males don’t survive)

Question 5

What are the clinical manifestations in Fragile X?

Answer 5

ID, large ears, long face, macroorchidism, autism, hand flapping, aggression

Question 5

What is the normal CGG repeat range?

Answer 5

6-45

Question 6

What are the clinical manifestation of Rett Syndrome?

Answer 6

loss of coordination and communication skills; abnormal hand flapping; failure to thrive; seizures

Question 7

Clinical manifestations of Hypophosphatemic Rickets?

Answer 7

bone deformities, short stature, hypophosphatemia

Question 8

There are no _____ transmissions in X-linked disorders.

Answer 8

male to male

Question 9

What are the signs and symptoms of Becker Muscular Dystrophy?

Answer 9

same as DMD but later onset (some Dystrophin is made)

Question 9

What gene is mutated in hemophilia A? What chromosome? What is it caused by?

Answer 9

F8; X chromosome; inversion

Question 10

Females can be affected by _____ but not by _____.

Answer 10

X-linked dominant; X-linked recessive

Question 11

How do X-linked recessive disorders occur?

Answer 11

from lyonization

Question 12

What is the new mutation rate in Rett Syndrome?

Answer 12

95%

Question 13

What is the repeat in Fragile X?

Answer 13

CGG

Question 15

What is the incidence rate of Fragile X?

Answer 15

1:2500 males; 1:7000 females

Question 17

X-linked recessive disorders show the phenotype in ______ males and _______ females.

Answer 17

all; homozygous

Question 18

What is the incidence rate of Becker Muscular Dystrophy?

Answer 18

3:100,000

Question 19

What is the incidence rate of Duchenne Muscular Dystrophy?

Answer 19

1:3600

Question 20

What is the mutated gene in Fragile X? Which chromosome?

Answer 20

FMR1 on the X chromosome

Question 21

What is the transmission bias for Fragile X?

Answer 21

maternal

Question 22

What gene is mutated in Hypophosphatemic Rickets?

Answer 22

PHEX

Question 22

What is the incidence rate of hemophilia A?

Answer 22

1:4000 males

Question 24

What is the mutation in Rett Syndrome? Where is it located?

Answer 24

MECP2 gene on X chromosome

Question 25

What is the result of a PHEX gene mutation??

Answer 25

kidneys cannot reabsorb phosphate into the blood; soft bones result

Question 26

lyonization

Answer 26

silencing of one X chromosome

Question 27

What is the difference between DMD-associated DCM and DMD?

Answer 27

no involvement in the skeletal muscle in DMD-associated DCM

Question 29

Hypophosphatemic Rickets incidence rate?

Answer 29

1:20,000

Question 30

What are the signs and symptoms of hemophilia A?

Answer 30

bleeding into joints, muscles, head, bruising, delayed healing

Question 32

What is the protein of interest in Rett Syndrome? What does it do?

Answer 32

Methyl CpG binding protein; normal function of nerve cells

Question 33

What are the symptoms of Duchenne Muscular Dystrophy?

Answer 33

progressive muscular degeneration; calf hypertrophy; early death; Gower maneuver

Question 34

What is FMR1 essential for?

Answer 34

normal cognitive development and female reproductive function

Question 35

X-linked dominant inheritance is expressed in male _____ and female _____.

Answer 35

hemizygotes; heterozygotes

Question 36

What # of repeats is needed for full Fragile X mutation?

Answer 36

more than 200