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Flashcards in genetics Deck (24)
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1
Q

Downs syndrome usually occurs due to

A

nondisjunction in Meiosis in the Ovum
(can also occur due to robertsonian translocation)
-advanced maternal age is a risk factor

2
Q

pts with down’s syndrome at risk for which cancers

A

AML ALL

3
Q

acetylation of histones

A

enhances gene transcription

4
Q

deacetylation of histones

A

silences the genes

-in HD, the mt huntington gene enhances the deacetylation of genes

5
Q

hypermethylation of a transcription gene

A

leads to gene silencing

6
Q

neonate with lymphemeda and cystic hygromas

A

tuners syndrome

7
Q

t (15,17)

A

acute promyelocytic leukemia
-PML/RARalpha
M3 varian of AML
-younger pts, on smear see many auer rods, in

8
Q

t(8,14)

A

Burkitts lymphoma

-c-myc translocated to immunoglobin gnee

9
Q

t (9,22)

A

philadelphia chromosome, CML, bcr-abl

10
Q

t (11, 14)

A

mantle cell B lymphoma

-activation of cyclin D gene

11
Q

situs inversus + recurrent sinopulmonary infections

A

kartagener syndrome (immotile cilia syndrome)
-due to failure of dyenin arms to develop normally
-causes decreased clearing of epithelial cells
leads to infertility in men and can lead to infertility in women as well due to decreased fallopian tube cilia mobility
-autosomal recessive

12
Q

neonate with low-set ears, clenched fists, overlapping fingers, micrognathia, microcephaly, arnold chiari, rocker bottom feet, HYPERtonia, VSD, PDA, Meckels, malrotation

A

Edwards, trisomy 18

-key abnormal hand (clenched with overlapping fingers)

13
Q

cleft lip/palate, micropthalmia, coloboma, cyclops, deafness, scalp defects, PDA

A

Patau, trisomy 12

-most die within week and others rarely survive past 6 months,

14
Q

ataxia, cardiomyopathy, pes cavus, hammer toes, kyphoscoliosis,

A

Friedrich ataxia
-chromosome 9, increaased trinucleotide repeats
-10% also develop Diabetes mellitus
death usually by cardiomyopathy and/or bulbar dysfunction

15
Q

multiple telangiectasia of skin and mucosa with recurrent epistaxis

A

hereditary hemorrhagic telangiectasia (Osler-Rendu-Weber syndrome)

16
Q

FGFR 3 mutation

A

achondroplasia (dwarfism)
autosomal dominant, lethan in homozygous dominant
-therfore heterozygous person has 50% chance of having a short kid

17
Q

ectopia lensis, MR, vascular thromboses, marfanoid, osteoporosis

A

homocystinuria,
cystathionine beta synthase deficiency
an example of pleiotrophy

18
Q

increased AFP

increased Ach

A

Neural tube defects

19
Q

hypotonia, poor feeding, macroglossia, jaundice, constipation, hoarse cry

A

congenital hypothyroidism
prevents normal brain devleopment and myelination during early life
-also at higher risk of congenital heart risk (ASD/VSD)
-irreversible mental retardation,
-a normal screening test

20
Q

chromosome 22 long arm deletion

A

DiGeorge
CATCH 22
Cleft lip/cardiac anomalies like interrupted aortic arch
Abnormal facies
Thymic hypoplasia-recurrent viral infection due to decreased T cell maturation
Hypocalcemia due to pit abnormalities

21
Q

t (14,18)

A

follicular lymphoma (a non-Hodgkin lymphoma)
leading to overexpression of bcl-2–> a proto-oncogene tha tprevents the release of pro-apoptotic factors)
14-immunoglobin heavy chain enhancer

22
Q

histone located outside of nucleosome core

A

Histone H1, aid in DNA packing of regions between each core making entire structure more tight
inside (H2A, H2B, H3, H4)X2

23
Q

genetics of Alzheimer’s

A

ApoE4 associated with familial late onset AD

Presenilin 1 on chr 14, presenilin 2 on chr 1, and amyloid precursor protein on 21 associated with early onset AD

24
Q

polygenic conditions

A
  • androgenetic alopecia
  • epilepsy
  • schizophrenia
  • glaucoma
  • ischemic heart disease
  • hypertension
  • TIID
  • malignancy