Genetics and Congenital Disorders

Question 1

Alleles are

Answer 1

The two members of a gene pair

Question 2

Homozygous means

Answer 2

The two members of a gene pair are the same

Question 3

Heterozygous means

Answer 3

The two members of a gene pair are different

Question 4

Genotype is the

Answer 4

Genetic composition of a person

Question 5

Phenotype is the

Answer 5

Observable expression of a genotype

Question 6

A dominant allele is when

Answer 6

The trait is phenotypically seen in the heterozygote

Question 7

A recessive allele is when

Answer 7

The trait is phenotypically seen only in the homozygote

Question 8

Gene mutation is

Answer 8

A biochemical event that produces a new allele for a particular gene

Question 9

Reduced penetrance is where

Answer 9

A person inherits a dominant mutant gene but fails to exhibit the associate phenotype

Question 10

Variable expressivity is where

Answer 10

Dominant disorders can be expressed differently in people who carry the mutant gene

Question 11

Single gene disorders are caused by

Answer 11

DNA changes in one particular gene/allele

Question 12

The pattern of inheritance depends on

Answer 12

The phenotype and whether the defective gene is on an autosomal or sex chromosome

Question 13

In autosomal dominant disorders a

Answer 13

Single mutant allele from an affected parent is transmitted to an offspring

Question 14

Does sex matter in autosomal dominant disorders?

Answer 14

No

Question 15

In autosomal dominant disorders, the affected parent has what chance of transmitting the disorder to their offspring?

Answer 15

50%

Question 16

In autosomal dominant disorders, what is the chance that an unaffected sibling transmits the disorder?

Answer 16

0%

Question 17

Autosomal recessive disorders are

Answer 17

Manifested only when both members of the gene pair are affected

Question 18

In autosomal recessive disorders, both parents may be __ but are __

Answer 18

Unaffected

Carriers of the defective gene

Question 19

Which sex is affected by autosomal recessive disorders?

Answer 19

Both

Question 20

When giving birth, what are the risks for (see below) with an autosomal recessive disorder?

Affected Child
Carrier Child
Not affected or carrier child

Answer 20

1/4
2/4 (1/2)
1/4

Question 21

Sex-linked disorders are almost always associated with

Answer 21

The X chromosome

Question 22

Female chromosomes are

Answer 22

XX

Question 23

Male chromosomes are

Answer 23

XY

Question 24

Females rarely experience the effects of ___ because ___

Answer 24

The recessive defective gene

They have a normal X (dominant)

Question 25

The common pattern of inheritance regarding X-linked recessive disorders is

Answer 25

The unaffected mother is a carrier of the mutant allele

Question 26

T/F Inheritance patterns follow the same patterns as single-gene disorders

Answer 26

False;

These traits do not follow the same clear-cut pattern of inheritance as do single-gene disorders because the appearance of the disorder phenotype will be dependent on environmental changes in addition to genetic mutations.

Question 27

T/F Expression of the disorder always occurs later in life

Answer 27

False;

Disorders of multifactorial inheritance can be present at birth, or they may be expressed later in life.

Question 28

T/F Environmental factors play a significant role in development

Answer 28

True

Question 29

T/F Multifactorial congenital malformations usually involve multiple organs or tissues

Answer 29

False;

Multifactorial congenital malformations tend to involve a single organ or tissue derived from the same embryonic developmental field.

Question 30

T/F Risk for reoccurrence is high in future pregnancies

Answer 30

True

Question 31

T/F Cleft palate is an example of an inherited multifactorial disorder

Answer 31

True

Question 32

___ account for many genetic diseases, miscarriages, congenital malformations, and intellectual disability

Answer 32

Chromosomal disorders

Question 33

Structural alterations usually result from

Answer 33

Breakage in one or more of the chromosomes during meiosis followed by rearrangement or deletion of chromosome parts

Question 34

What is the most common chromosomal disorder?

Answer 34

Down Syndrome

Question 35

In down syndrome, there are __ chromosomes but ___

Answer 35

46

Trisomy at the 21st pair

Question 36

The manifestations of down syndrome

Answer 36

Epicanthal folds, slanted eyes, flat facial profile, growth failure, mental retardation, flat back of the head, malformed ears, large protruding tongue, congenital heart disease, intestinal malformations, acute lymphoblastic leukemia, short broad hands with simian crease, wide gap between first and second toes

Question 37

When is a woman most at risk for giving birth to a child with down syndrome? Why?

Answer 37

As she gets older; the theory is because women are born with all the eggs they will ever have, and as time goes on some of them change (get old)

Question 38

Turner syndrome affects __ and is due to

Answer 38

The sex chromosome

An absence of all or part of the X chromosome

Question 39

45, X/O is another term for

Answer 39

Turner Syndrome

Question 40

Turner Syndrome affects which sex?

Answer 40

Females

Question 41

The manifestations of Turner Syndrome

Answer 41

Small stature, low posterior hairline, webbed neck, broad chest with widely spaced nipples, coarctation of aorta and bicuspid aortic valve, poor breast development, wide carrying angle of arms, ovarian dysgenesis with primary amenorrhea, estrogen, and progesterone deficiencies and infertility, multiple pigmented nevi, retardation of bone age, lymphedema of hands and feet at birth and later

Question 42

Klinefelter Syndrome is

Answer 42

A chromosomal abnormality where males have an extra X chromosome

Question 43

47, XXY is another term for

Answer 43

Klinefelter Syndrome

Question 44

The manifestations of Klinefelter Syndrome

Answer 44

Tall stature, lack of facial hair, narrow shoulders, gynecomastia, long arms and legs, wide hips, decreased pubic hair, testicular atrophy, infertility

Question 45

Period of vulnerability is

Answer 45

The period in which an embryo is most easily disturbed (15-60 days after conception when cell differentiation and organ development happens)

Question 46

`A teratogenic agent is

Answer 46

A chemical, physical, or biologic agent that can disturb the development of an embryo or fetus

Question 47

A mutagenic agent is

Answer 47

inducing or capable of inducing genetic mutation

Question 48

Is radiation teratogenic or mutagenic?

Answer 48

Both

Question 49

Radiation can cause

Answer 49

Microcephaly
Skeletal malformation
Mental retardation

Question 50

Chemicals and drugs can

Answer 50

Cross the placenta and damage the embryo and fetus

Question 51

Example of environmental teratogens

Answer 51

Organic mercurials

Question 52

What are some drugs that are known to cause fetal abnormalities?

Answer 52

Thalidomide, chemo agents, anticoagulant coumadin, anticonvulsant meds

Question 53

Many organisms cross the ___ and enter ___ resulting in ___

Answer 53

Placenta
Fetal circulation
Malformations