NCC content

Question 1

3 main types of genetic disease

Answer 1

• chromosomal
• single gene (mendelian) = dominant, recessive, x-linked
• multificatorial

Question 2

what is the best test to order if there are concerns for a genetic disorder?

Answer 2

microarray

Question 3

what is the only reason to order chromosomes at this point?

Answer 3

• trisomy 13, 18, 21

- ambiguous genitalia (X, Y)

Question 4

what is translocation down syndrome?

Answer 4

children with this have two copies of chromosome 21, but a third copy of 21 is stuck to another chromosome

Question 5

if a parent is a carrier of balanced translocation down syndrome, what are the chances the child will have it?

Answer 5

100%

Question 6

what is mosaicism?

Answer 6

abnormal cell division resulting in two or more types cells containing different numbers of chromosomes

Question 7

what cancer are trisomy 21 patients prone to having?

Answer 7

acute myeloid leukemia

Question 8

about trisomy 13

Answer 8

the forebrain is involved 
-olfactory and optic nerves
microcephaly
cleft lip and/or palate
single umbilical artery 
**cutis aplasia of scalp**
polydactyly
-VSD, PDA, ASD

Question 9

what is another name for trisomy 13?

Answer 9

patau syndrome

Question 10

about trisomy 18

Answer 10

**IUGR & short sternum**
prominent occiput
low set malformed ears
short palpebral fissures
clenched hand with overlapping fingers
rocker bottom feet

Question 11

what is another name for trisomy 18?

Answer 11

edwards syndrome

Question 12

what is the only nondisjunction not related to the mother’s age?

Answer 12

turner syndrome

Question 13

what is turner syndrome?

Answer 13

45, X

Question 14

define nondisjunction

Answer 14

failure of sister chromatids to separate properly during cell division

Question 15

what are other names for 22q11.2 deletion?

Answer 15

velo-cardio-facial syndrome

DiGeorge syndrome

Question 16

CATCH22

Answer 16

Conotruncal cardiac defects (IAA, Truncus, TOF)
Abnormal facies
Thymic aplasia/hypoplasia
Clefting/palate abnormalities
Hypoparathyroid (hypocalcemia)
22q11.2

Question 17

how often is Digeorge inherited?

Answer 17

10% of cases

Question 18

parents with inherited Digeorge have what chance of passing it on

Answer 18

50% with each pregnancy

Question 19

facial features of Digeorge

Answer 19

• hooded eyelids
• short and narrow palpebral fissures
• bulbous nose or bifid nasal tip
• microstomia
• ears (deficient upper helix, overflowed helix, small or C-shaped ear)

Question 20

DiGeorge phenotype without 22q11.2 deletion

Answer 20

• do not rely on fish results only
• 10% with phenotype are negative on probe
• they are still DiGeorge and need to be treated accordingly

Question 21

What is 7q11 deletion?

Answer 21

Williams syndrome

• intermittent infantile hypercalcemia
• growth retardation
• mild to moderate mental retardation
• outgoing friendly personality
• supravalvular aortic stenosis, peripheral pulmonic stenosis

Question 22

7q11 deletion facies

Answer 22

• periorbital fullness
• bitemporal narrowing
• short nose
• full nasal tip
• malar hypoplasia
• wide mouth, small jaw
• IUGR/SGA

Question 23

angelman’s

Answer 23

missing mother’s chromosome 15 info

Question 24

prader-willi

Answer 24

missing father’s chromosome 15 info

Question 25

routine chromosomes abnormal detection rate is:

Answer 25

5%

Question 26

microarray abnormal detection rate is:

Answer 26

18-20%

Question 27

define myotonic dystrophy

Answer 27

hyperactivity of the muscle cell membrane; unable to relax the muscles once contracted; transferred autosomal dominant through mothers

Question 28

what does charge stand for?

Answer 28

``` Colobomas Heart (aortic valve stenosis, IAA, TGA, coarc) Atresia of choanae Retardation (of growth and development) Genital hypoplasia in males Ear anomalies and deafness ```

Question 29

how is charge passed on?

Answer 29

autosomal dominant

Question 30

describe congenital central hypoventilation syndrome

Answer 30

- generalized autonomic nervous system dysfunction - characterized by adequate ventilation while the affected individual is awake and by hypoventilation during sleep - can also have Hirschsprungs, neuroblastoma

Question 31

how is congenital central hypoventilation syndrome passed on?

Answer 31

-autosomal dominant

Question 32

what is the most common autosomal recessive disorder?

Answer 32

cystic fibrosis

Question 33

X-linked mode of inheritance

Answer 33

mutations in genes on the X chromosome

Question 34

X-linked dominant

Answer 34

fathers cannot pass X-linked traits to their sons | -can be lethal in males

Question 35

X-linked recessive

Answer 35

fathers cannot pass X-linked traits to their sons - males are more frequently affected than females - rarely have affected females

Question 36

what type of inheritance is Fragile X?

Answer 36

x-linked dominant

Question 37

are males and females more severely affected by fragile X?

Answer 37

males

Question 38

what type of inheritance is hemophilia A

Answer 38

x-linked recessive

Question 39

what type of inheritance is Duchenne muscular dystrophy?

Answer 39

x-linked recessive