Cytogenetic/Whole Chromosome Disorders

Question 0

what is the cause of Down syndrome

Answer 0

meiotic non-disjunction during gametogenesis in the mom

–> happens due to increasing maternal age

Question 1

name the 3 trisomies that are compatible with life

Answer 1

1. trisomy 13= Patau
2. Trisomy 18= Edwards
3. Trisomy 21= Down Syndrome

Question 2

MOA for familial inherited Down Syndrome

Answer 2

ROBERTSONIAN TRANSLOCATION
normal chromosome # but the long arm of 21 translocated to chromosome 14
short arms= throw away/junk DNA

Question 3

what is the karyotype for familial inherited Down syndrome

Answer 3

45 XX -14, -21, + (14q21q)
compatible with life because have both long arms of DNA (q)
you just got rid of the short arms= junk DNA
46 XY, + (14q21q)

Question 4

what can cause spontaneous abortions

Answer 4

robertsonian translocation that causes a deletion of one of the q arms of 14 or 21
must have q arm of both chromosomes to be compatible with life
long arm of chromosome 21= most important

Question 5

what is the saying for chromosome 22q 11.2 deletion syndrome

Answer 5

Cadiac defects
Ass face
Thymic hypoplasia
Cleft palate
Hypocalcemia
22= chromosome involved

Question 6

which parts of CATCH 22 do you see more in Digeorge?

Answer 6

hypocalcemia

Question 7

which parts of CATCH 22 do you see the most in velocardiofacial syndrome

Answer 7

cardiac defects
ass face
cleft palate

Question 8

what are the 3 sec chromosome syndromes we care about

Answer 8

1. Klinefelter syndrome= 47 XXY
2. Turner syndrome= 45 X
3. XYY males

Question 9

why do you see feminization in males with klinefelters syndrome

Answer 9

some genes on the extra X chromosome escape inactivation which leads to feminization

Question 10

What other things do you see in males with klinefelters syndrome

Answer 10

1. gynecomastia= growth of abnormally large breasts in males

2. SLE (systemic lupus erythematosus)–> female dominated disease

Question 11

symptoms of Klinefelters syndrome

Answer 11

1. high FSH and LH
2. tall and slim
3. eunuchoid stature
4. gynechomastia
5. Barr body= inactivated X chromosome

Question 12

Turners syndrome=

Answer 12

45X

need at least 1 X to be compatible with life

Question 13

what test is used to determine if child has Turner syndrome

Answer 13

nuchal translucency test
-measure space on back of neck

if kid cant deal with fluid in womb–> pro cardia issue/defect
so get fluid accumulation in nuchal translucency test
if accumulation stays–> get webbed neck/increased nuchal folds

Question 14

symptoms of turners syndrome= XO

Answer 14

1. small stature
2. webbed neck–> due to cardiac defect
3. coarctation of aorta
4. poor breast development
5. rudimentary ovaries–> cant menstrate

Question 15

if you see what 2 things you make you say a child might have turners syndrome?

Answer 15

female with

1. hypoplastic left heart or
2. coarctation of aorta

Question 16

what 2 things are associated with XYY males

Answer 16

1. taller stature

2. cystic acne