Q1 Behavior Traits, Complex Traits, And Epigenetics

Question 1

a genetic etiology of autism is more likely when autistic characteristics are _______

Answer 1

• part of a more complex picture

Question 2

for autism there is a higher risk of recurrence when the first affected child is of the ____ commonly affected sex
- which sex is this

Answer 2

• less commonly

- female

Question 3

Rett syndrome is seen in which sex

- why

Answer 3

• females

- male MECP2 variant is lethal

Question 4

what condition shows:

• regression of speech/motor milestones after 6-18 months
• seizures, growth retardation and progressive cognitive and motor impairment
• partial of complete loss of acquired purposeful hand skills with stereotypic hand movements

Answer 4

• Rett syndrome

Question 5

you see a child with wringing/squeezing or clapping/tapping of hands, what might they have?

Answer 5

• Rett syndrome

Question 6

what gene is affected in Rett syndrome?

Answer 6

• MECP2

Question 7

what is an example of a monogenic disorder that may present with development delay/autism

Answer 7

• Rett syndrome

Question 8

which is an example of an x-linked condition that is lethal in males

Answer 8

• Rett syndrome

Question 9

what is the 1st tier test in genetic testing for autism spectrum disorders

Answer 9

• 3 generation family history

- chromosomal microarray

Question 10

when do you use single-gene testing for autism

Answer 10

• fragile X

- MECP2 spectrum disorders (Rett syndrome)

Question 11

chromosome analysis is typically indicated to evaluate for clinically-suspected ______ or family/reproductive history suggestive of _____

Answer 11

• aneuploidy

- rearrangments

Question 12

copy number variants have been identified in a small number of individuals with _________
- most common deletion

Answer 12

• schizophrenia

- 22q11 (DiGeorge)

Question 13

what is a genome wide association study

how is this typically performed

Answer 13

• look at markers for people who have a certain condition and see what markers they share
• SNP arrays

Question 14

is a P value < 0.05 enough for a genome wide association study

Answer 14

• no

Question 15

do genome wide association studies identify causative variants
- what do they show

Answer 15

• no

- they show association

Question 16

what refers to heritable cellular and physiological traits that are not due to genetic sequence variations

Answer 16

• epigenetics

Question 17

the binding of epigenetic factors to histone tails alters what

Answer 17

• the extent to which DNA is wrapped around histones

- availability of genes in DNA to be activated

Question 18

DNA methylation is a covalent modification of _____ residues at CpG dinucleotides

Answer 18

• cytosine

Question 19

importance of DNA methylation

Answer 19

• chromosome stability
• X-chromosome inactivation
• transcriptional silencing

Question 20

fragile X is a _______ disorder

Answer 20

• triplet repeat

Question 21

acetylated histones means genes are switched on/off?

Answer 21

• on

Question 22

methylation cytosines means that genes are switched on/off?

Answer 22

• off

Question 23

MECP2 is essential for ____ cell function

Answer 23

• nerve

Question 24

role of MECP2

Answer 24

• binds methylated DNA

- regulates expression of multiple genes

Question 25

imprinted genes may be primarily expressed from the allele inherited from ____ of the parents

Answer 25

- one

Question 26

what is an epigenetic phenomenon through which the expression of certain genes is regulated in a manner specific to the parent of origin

Answer 26

- genomic imprinting

Question 27

is the offspring's sex relevant in genomic imprinting?

Answer 27

- no

Question 28

the epigenetic mark is established in _____ and persists in ______ cells

Answer 28

- established in gametogenesis | - persists in somatic cells

Question 29

imprinting is reset in ______ (what stage)

Answer 29

- gametogenesis

Question 30

what is the parental conflict hypothesis

Answer 30

- paternally-expressed genes promote offspring growth, at expense of maternal resources - maternally-expressed genes may seek to balance resources by limiting offspring growth

Question 31

epimutations alter the normal ______ of an imprinted gene

Answer 31

- expression patterns

Question 32

deletion/mutation _____ the allele that should be active

Answer 32

- disrupt

Question 33

uniparental disomy may result in _____ chromosomal region with _____ epigenetic signal

Answer 33

- two chromosomal regions | - same epigenetic signals

Question 34

what is the name for inheritance of both copies of a chromosome from the same parent without contribution from the other parent

Answer 34

- uniparental disomy

Question 35

mechanisms of uniparental disomy

Answer 35

- trisomy rescue - monosomy rescue - gametic complementation - meiotic errors - somatic recombination

Question 36

what is the name for inheriting two different chromosomes from the same parent

Answer 36

- heterodisomy

Question 37

what is the name for inheriting two copies of the same chromosome from the same parent what can this result in

Answer 37

- isodisomy | - manifestation of recessive conditions

Question 38

what condition is associated with hypotonia, and poor feeding at birth-2 years and then being overweight with hyperphagia after age 2

Answer 38

- Prader-Willi syndrome

Question 39

which condition is present with microcephaly, seizures, speech impairment, and a behavioral phenotypes consistent with frequent/inappropriate paroxysms of laughter

Answer 39

- Angelman syndrome

Question 40

Prader-Willi syndrome and Angelman syndrome involved ____ genes on which gene most common cause

Answer 40

- reciprocally-imprinted - on gene 15 - de novo deletions

Question 41

what allele is paternally imprinted (silenced) in the brain what is it silenced by

Answer 41

- UBE3A | - antisense non-coding RNA

Question 42

Familial Angelman Syndrome results when a pathogenic _______ variant is inherited on the ________ allele

Answer 42

- UBE3A | - maternal

Question 43

why does it not matter if the paternal UBE3A has a mutation

Answer 43

- it is silenced in the brain anyway

Question 44

what condition do you see Macrosomnia (large baby), macroglossia, embryonal tumor?

Answer 44

- Beckwith-Wiedeman Syndrome