Genetic Inheritance

Question 1

A _____ disorder has the same phenotype for heterozygous and homozygous state.

Answer 1

Dominant

Question 2

______ is when a more severe phenotype is seen with both affected alleles compared to one affected allele. ______ is when both alleles are manifested in the phenotype (example: blood type)

Answer 2

Semidominant
Codominant

Question 3

What trait is this representing

Answer 3

Dominant trait

Question 4

Relative risk depends on the _____ of the mutant gene/disease

Answer 4

Penetrance

Question 5

There is a_____ risk to each son or daughter to inherit a mutant dominant gene.

Answer 5

50%

Question 6

If you see male to male transition, it is not _____ inheritance

Answer 6

X-linked

Question 7

What type of inheritance is this showing

Answer 7

Autosomal dominant inheritance

Question 8

What type of inheritance is this showing

Answer 8

Dominant inheritance, the skipped generation shows reduced penetrance

Question 9

____ ___ _____ is seen in my types of cancer. This is when one inherited mutation is followed by loss of function of the second good allele. This is also described as _____ fashion at the level of organism but are _____ at the level of the cell.

Answer 9

Loss of heterozygosity
Dominant
Recessive

Question 10

Loss of heterozygosity is also know as _____ ____ hypothesis.

Answer 10

Knudson’s two hit

Question 11

_____ _____ is an autosomal dominant disease caused by mutations in the LDLR gene, but can be caused by other genes, thus demonstrates _____ heterogeneity

Answer 11

Familial hypercholesterolemia
Locus

Question 12

Neurofibromatosis has 100% penetrance but _____ ____, meaning the phenotypes vary in severity based on the nature of the mutation in the NF1 gene. This disease causes tumors on the skin which show extensive _____, meaning phenotypic expression in a wide range of tissues.

Answer 12

Variable expressivity
Extensive pleiotropy

Question 13

What does this show?

Answer 13

A dominant inheritance. The mutation likely arose in a proband of generation III, possibly a mutation in the germ line of parents

Question 14

______ is a dominant inheritance disease classified by the gain of function of a growth factor receptor. Homozygous is lethal.

Answer 14

Achondroplasia

Question 15

LDLR Familial hypercholesterolemia is a ______ inherited disease. It also shows semidominance. This is an example of a disease where the deficiency in one tissue (_____) leads to a clinical phenotype in a different tissue (_____)

Answer 15

Dominant
Liver
Cardiovascular

Question 16

_____ ____ is a dominant inheritance disease. A ____ variant in collagen genes form a more severe form of this disease. Altered collagen can’t interact with normal collagen. This interferes with the normal function of the other ____.

Answer 16

Osteogenesis imperfecta
Missense
Allele

Question 17

____ ____ phenotypes in autosomal dominant disorders is when one sex is more affected than the other or only one sex is affected. An example is male-limited precocious puberty: growth spurt at the age of 4

Answer 17

Sex-limited

Question 18

What is this pedigree showing?

Answer 18

Sex-limited phenotype in autosomal dominant inheritance. Only affecting males and there is male to male inheritance so it can’t be X-linked

Question 19

Some phenotypes are dominant due to ___ __ ___, meaning the new variant has a new or altered function. ____ ____ ____, meaning interference with other gene products that work together. _______ meaning too little protein is made due to one copy of the gene missing. Or ____ ____ hypothesis, meaning one allele is defective and the other allele taken out (recessive on a cellular level).

Answer 19

Gain of function
Dominant negative effect
Haploinsufficiency
Knudsen 2hit

Question 20

What does this show?

Answer 20

Dominant inheritance with variable expression and incomplete penetrance

Question 21

When affected individuals in the same family (same genetic variant) have different features of the disease this is called ___ ___.

Answer 21

Variable expressivity

Question 22

_____ is the proportion of individuals carrying a particular variant that manifests the associated phenotype

Answer 22

Penetrance

Question 23

_____ is when successive generations have more severe or earlier age of onset of the disease.

Answer 23

Anticipation

Question 24

In dominant inheritance parents are often _____. In recessive parents are usually not _____.

Answer 24

Affected
Affected

Question 25

______ means that both alleles of the gene have to be affected to show the phenotype. ____ _____ means it can be two different mutant alleles but both are nonfunctional.

Answer 25

Recessive Compound heterozygous

Question 26

What does this show?

Answer 26

Recessive inheritance

Question 27

In recessive inheritance there is a ____ risk to each son and daughter

Answer 27

25%

Question 28

_____ inheritance may be more common in certain populations.

Answer 28

Recessive

Question 29

What does this show?

Answer 29

Recessive inheritance

Question 30

What does the thicker line show?

Answer 30

Consanguinity: parents are closely related individuals like 1st cousins

Question 31

What does this show?

Answer 31

Autosomal recessive with carriers and consanguinity

Question 32

What does this show?

Answer 32

Autosomal recessive Clue: only in one generation, parents are not affected

Question 33

______ is the most common inherited disease in the world. Homozygous is ____. Heterozygous shows a resistance to ____. Heterozygous advantage

Answer 33

Hemoglobinapathies (sickle cell anemia) Lethal Malaria

Question 34

____ ____ is due to variants in CFTR. It has ____ heterogeneity meaning many different alleles cause it.

Answer 34

Cystic fibrosis Allelic

Question 35

_____ is caused by mutations in phenylalanine hudroxylase gene (PAH). It is tested in new borns. ____ inheritance, thus the risk for passing it on to kids is 25%

Answer 35

Phenylketonuria (PKU) Recessive

Question 36

____ ____ autosomal recessive disorders are when both sexes can develop a disease but one sex has a significantly higher frequency

Answer 36

Sex-influenced

Question 37

Biochemical disorders caused by enzyme activity decencies are very frequently autosomal _____.

Answer 37

Recessive

Question 38

If the functioning allele is sufficient to prevent disease state, the disease inherits as ____.

Answer 38

Recessive

Question 39

One consequence of ____ is that many rare recessive disorders are observed at a much higher frequency. And example is Tay-Sachs

Answer 39

Inbreeding

Question 40

What does this show?

Answer 40

X-linked inheritance

Question 41

Males have one X chromosome and are all _____ for X-linked disorders. Females can be ____ or ____.

Answer 41

Hemizygous Homozygous Heterozygous

Question 42

Sons of affected males are never affected in ____ inheritance

Answer 42

X-linked

Question 43

In heterozygous mothers for an X-linked disorder, ____ percent of sons are hemizygous. ____ percent of daughters are heterozygous (carriers)

Answer 43

50 50

Question 44

In mammalian female somatic cells, one X chromosome is active and the other one condenses. The condensed X is called a ___ ___. Overall this is called ___ ____ and occurs randomly.

Answer 44

Barr body X inactivation

Question 45

X inactivation is _____ meaning after one X chromosome is inactivated, all of that cell’s descendants have the same inactive X

Answer 45

Clonal

Question 46

____ ____ is an example of X inactivation. Swirls of disease is seen on the skin.

Answer 46

Incontinentia pigmenti

Question 47

Daughter of hemizygous males in and X-linked disorder, are all _____ because dad can only donate his one “bad” X chromosome to daughters.

Answer 47

Carriers

Question 48

_____ dominant disorders are rare. Only about 20 genes on the Y chromosome

Answer 48

Y-linked

Question 49

Dysfunction of mitochondria occurs when a ____ that is needed by the mitochondria is missing. This causes a lack of ___ production.

Answer 49

Protein ATP

Question 50

Most mitochondrial disorders result from variants in the DNA inside the _____.

Answer 50

Nucleus

Question 51

Almost all mitochondria come from the ____. Pedigree will show affected females in the generation above.

Answer 51

Mother

Question 52

What does this show?

Answer 52

Maternal inheritance in mitochondrial disorder

Question 53

In mitochondrial disorders, _____ refers to the coexistence of multiple mitochondrial DNA types within a single cell. The disorder can vary through the body from tissue to tissue. Can vary by age and activity levels.

Answer 53

Heteroplasmy

Question 54

In mitochondrial disorders, ____ ____ refers to the absence of tightly controlled segregation in mitochondrial DNA. Mitochondria are randomly distributed between the two daughter cells.

Answer 54

Replicative segregation

Question 55

In mitochondrial disorders, ___ ___ refers to how many mutant mitochondria are needed to express a disease. Symptoms depend on whether or not tissue is affected depends on the metabolic needs of the tissue

Answer 55

Threshold effect

Question 56

Mitotic disorders most heavily affect the ____, ____, and ____

Answer 56

Brain Heart Liver

Question 57

An example of _____ ____ is X inactivation. This also occurs in early development, one mutation will be passed on to daughter cells. They go on to form a mutated tissue.

Answer 57

Mutational mosaicism

Question 58

There is controversial evidence of ____ ___ ____, meaning non Mendelian inheritance (non gene based inheritance). This stresses the importance of environmental factors affecting one generation that affects the phenotype of a later generation.

Answer 58

Transgenerational epigenetic inheritance