Lecture 7 - Unusual Patterns of Inheritance

Question 1

the _____ region is the segment of the X and y chromosomes located at the most distal portion of their respective p and q arms. crossing over can occur during ____ meiosis

Answer 1

pseudoautosomal (PAR),
male

ie X and Y recombination

Question 2

pseudoautosomal traits can have ___ to ____ transmission. the pseudoautosomal region of the X chromosome (is or is not) inactivated on the lyonized X in females

Answer 2

male to male;

is not

Question 3

the PAR contains the ____ ____ homeobox containing gene. need (one or 2) copies for normal stature?

Answer 3

short stature;
2

so if only 1 copy–>short stature (turner)

Question 4

pseudoautosomal _____ is a dominantly inherited skeletal defect with disproportionate short stature and deformity of the ____, due to mutation of short stature homeobox.

Answer 4

dyschondrosteosis;

forearm

Question 5

what is another gene that can undergo pseudoautosomal inheritance?

Answer 5

SRY/testis determining factor

Question 6

presence of the SRY gene on an X chromosome would cause a XX person to be phenotypically ___. the SRY gene causes production of what?

Answer 6

male (and infertile);

testis determining factor

Question 7

in ____an offspring receives 2 copies of a chromosome from one parent and no copies from the other parent

Answer 7

uniparental disomy (UPD)

Question 8

UPD:
heterodisomy (heterozygous) indicates a _____ error. Isodisomy (homozygous) indicates a ____ error or a postzygotic chromosomal ____ of one pair of chromosomes and ____ of the original pair.

Answer 8

meiosis 1;
meisos 2;
duplication;
loss

Question 9

UPD:

we often the presume the fetus was originally ___ followed by ____ of a chromosome aka ____ _____

Answer 9

trisomic;
loss;
trisomic rescue

Question 10

genomic imprinting (GI) = differential expression of alleles of a gene in ___ cells. involves a form of gene marking that is (reversible or irreversible?) ie _____ turns an allele off

Answer 10

somatic;
reversible;
hypermethylation

is a normal process

Question 11

2 diseases with genomic imprinting problems?

what chromosome are these associated with

Answer 11

prader-willi,
angelman;

both on chrom 15

Question 12

2 reproductive disease than may be caused by imprinting

Answer 12

complete hydatidiform mole;

ovarian teratoma

Question 13

complete hydatidiform mole = ____ genomes only;

ovarian teratoma = ____ genomes only

Answer 13

paternal, maternal

Question 14

prader willi syndrome (PWS):

the ____ imprinted gene is normally silent. the ____ gene is mutated or deleted

Answer 14

maternal;

Paternal (P for PWS)

Question 15

PWS symptoms:
hyper____, ____, intellectual disability or no?;
____ gonads; ___tonia

Answer 15

phagia, obesity, intellectual disability (moderate);
small, hypo

also short stature

Question 16

25% of cases of PWS are caused by ____ ___ _____

Answer 16

maternal uniparental disomy (ie both chromes from mom)

Question 17

angelman syndrome (AMS):
the \_\_\_\_ imprinted gene is normally silent. 
the \_\_\_\_ gene is mutated or deleted

Answer 17

paternal;

maternal (Maternal for Man)

Question 18

AMS:
aka “____ ____” syndrome. inappropriate ____, intellectual disability or no?;
sizures, ataxia

Answer 18

happy puppet;
laughter;
yes (severe)

Question 19

AMS:
5% cases due to ____ ____ ____;
other cases are due to mutation in UBE3A, which codes for ______

Answer 19

parental uniparental disomy (ie both chromes from dad);

ubiquitin-protein ligase

Question 20

AMS:

UBE3A is usually only expressed in the ____ (ie tissue specific)

Answer 20

brain

Question 21

imprinting:
occurs before or after fertilization?
must be ____ and is (reversible or irreversible) on passage through the opposite sex

Answer 21

before;
erased, reversible

ie male sperm doesn’t pass maternally imprinted chrome to male gametes (See ppt)

Question 22

mitochondria DNA:
lacks ____ and ____ = increased mutation rate;
inheritance is ____;
DNA is ____

Answer 22

proofreading, DNA-repair;
MATERNAL;
circular

Question 23

mitochondrial myopathies:
usually disorders of ____;
present with myopathy, ____ ____, and ___ probs

Answer 23

Oxidative phosphorylation;

lactic acidosis, CNS

Question 24

_____ is the presence of both normal and mutated mtDNA in a cell, resulting in _____ expression of disease

Answer 24

heteroplasmy;
variable

homoplasmy is when you get all of same kind of mtDNA in a cell

Question 25

____ ____ means that MtDNA is sorted randomly and mitochonria also distribute randomly

Answer 25

replicative segregation

Question 26

the ____ ____: impact of mutation varies depending on the tissue, the timing, and the number of mutant mitochondrial per cell

Answer 26

threshold effect

Question 27

____ ____ = number of mtDNA is reduced then amplified in the mature oocyte

Answer 27

genetic bottleneck

Question 28

“ragged red fibers” are often seen in what mitochondrial disorder?

this is due to to decreased charged ___ = increased ____ _____

Answer 28

Myoclonic epilepsy with ragged red fibers = MERRF;
tRNA;
chain termination

Question 29

MERRF causes myopathy, ____ seizures, ____ (CNS thing), and ____ (sensory thing)

Answer 29

myoclonic;
dementia;
deafness