Patterns Of Inheritance

Question 1

Normally appear with equal frequency in both sexes (unless penetrance differs in males and females)

Answer 1

AUTOSOMAL RECESSIVE

Question 2

→ appear only when a person inherits two alleles for the trait, one from each parent

Answer 2

AUTOSOMAL RECESSIVE

Question 3

[AUTOSOMAL RECESSIVE]

Whenever both parents are heterozygous, approximately _____________ of the offspring are expected to express trait, but this ratio will not be obvious unless the family is large.

Answer 3

1/4

Question 4

When an affected person mates with
someone outside the family (aa x AA), usually
none of the children will display the trait,
although all will be carriers (heterozygous)

Answer 4

Autosomal Recessive

Question 5

[Term]
Mating between closely related people is
called _________

Answer 5

consanguinity

Question 6

[True or False]
In autosomal recessive:

Only when a person inherits two alleles for the trait, one from each parent

Answer 6

True

Question 7

[Tay-Sachs Disease]
→ children with Tay-Sachs disease appear healthy at birth but become listless and weak at about what age?

Answer 7

6 months age

Question 8

[Determine the Disease]
→ gradually, their physical and neurological conditions worsen, leading to blindness, deafness, and eventually death at 2 to 3 years of age

Answer 8

Tay-sachs disease

Question 9

→ the disease results from the accumulation of a lipid called GM2 ganglioside in the brain

Answer 9

Tay-sachs disease

Question 10

→ a normal component of brain cells, GM2 ganglioside is usually broken down by an enzyme called ___________________ but children with Tay-Sachs disease lack this enzyme

Answer 10

Hexosaminidase A

Question 11

[Determine the Deficiency]
→ ↑ chylomicrons
→ increased chylomicrons lead to Familial Chylomicronemia

Answer 11

Lipoprotein Lipase Deficiency

Question 12

→ increased chylomicrons lead to ___________________

Answer 12

Familial Chylomicronemia

Question 13

→ significantly reduced levels of HighDensity Lipoprotein (HDL)
→ caused by lack of ABCA1 gene (can be found in chromosome 9)

Answer 13

Tangier’s Disease

Question 14

[TANGIER’S DISEASE]
→ caused by lack of _________ gene (can be found in chromosome 9)

Answer 14

ABCA1 gene

Question 15

appear in both sexes with equal frequency, and both sexes are capable of transmitting these traits to appear to their offspring

Answer 15

Autosomal DOminant

Question 16

[TRUE OR FALSE]
Autosomal dominant traits do NOT skip generations

→ exceptions to this rule arise when people acquire the trait of a new mutation or when the trait has reduced penetrance

Answer 16

True

Question 17

blood cholesterol is greatly elevated owing to a defect in cholesterol transport

Answer 17

Familial Hypercholesterolemia

Question 18

→ ____________ is an essential component of cell membranes and is used in the synthesis of bile and salts and several hormones.

Answer 18

cholesterol

Question 19

This disease is usually considered an autosomal dominant disorder because heterozygotes are deficient in LDL receptors

→ in these people, too little cholesterol is removed from the blood, leading to elevated blood levels of cholesterol and increased risk of coronary artery disease

Answer 19

Familial Hypercholesterolemia

Question 20

Familial Hypercholesterolemia is due to a defect in the gene (located on human chromosome ____________ ) that normally codes for LDL receptor.

Answer 20

19

Question 21

[TRUE OR FALSE]
→ people heterozygous for familial hypercholesterolemia have blood LDL levels that are twice normal and usually have heart attacks by the age of 45.

Answer 21

False, should be 35 years old

Question 22

→ traits appear more frequently in males because males need inherit only a single copy of the allele to display the trait, whereas females must inherit two copies of the allele, one from each parent, to be affected

Answer 22

X-linked Recessive

Question 23

→ tends to skip generation
→ traits are not passed from father to son, because a son inherits his father’s Y chromosome, not his X

Answer 23

X-linked recessive

Question 24

→ also called CLASSICAL HEMOPHILIA
this disease results from the absence of a protein necessary for blood clot

Answer 24

Hemophilia A

Question 25

[HEMOPHILIA A]
→ results from abnormal or missing factor __________, one of the proteins in the clotting cascade

Answer 25

Factor VIII

Question 26

→ appear in males and females, although they often affect more females than males

→ males inherit an X-linked dominant trait only from his mother- the trait is not passed from father to son

Answer 26

X-Linked DOminant

Question 27

→ a female on the other hand, inherits an X - chromosome from both her mother and father; so, females can receive an X-linked trait from either parent

Answer 27

X-linked Dominant

Question 28

→ also called Familial Vitamin D-resistant rickets

Answer 28

Hypophosphatemia

Question 29

→ people with this trait have features that superficially resemble those produced by rickets: bone deformities, stiff spine and joints, bowed legs, and mild growth deficiencies

Answer 29

Familial Vitamin D-resistant rickets

Question 30

Classify: HYPOPHOSPHATEMIA

Answer 30

X-linked Dominant

Question 31

Classify: HEMOPHILIA A

Answer 31

X-linked recessive

Question 32

Classify: FAMILIAL HYPERCHOLESTROLEMIA

Answer 32

Autosomal dominant

Question 33

Classify: Tangier’s Disease

Answer 33

Autosomal Recessive

Question 34

Classify: Lipoprotein lipase deficiency

Answer 34

Autosomal Recessive

Question 35

Classify: Tay-Sachs Disease

Answer 35

Autosomal Recessive

Question 36

Classify: HYPERTRICHOSIS PINNAE AURIS

Answer 36

Y-linked Dominant

Question 37

→ exhibit a specific, easily recognized pattern of inheritance
→ only males are affected, and the trait is passed from father to son

Answer 37

Y-LINKED DOMINANT

Question 38

[True or False]
→ if a man is affected, all his male offsprings should also be affected

→ Y-linked traits do not skip generations

Answer 38

Both statements are true

Question 39

1. Appears in both sexes with equal frequency
2. Traits tends to skip generations
3. Affected offsprings are usually born to unaffected parents
4. When both parents are heterozygous , approximately ¼ of the offsprings will be affected
5. Appears more frequently among the children of consanguine marriages

Answer 39

Give the summary of main points for Autosomal Recessive

Question 40

1. Appears in both sexes with equal frequency
2. Both sexes transmit the trait to their offspring
3. Does not skip generation
4. Affected offspring must have an affected parent, unless they possess a new mutation
5. When one parent is affected (heterozygous) and the other parent is unaffected, approximately ½ of the offspring will be affected
6. Unaffected parents do not transmit the trait

Answer 40

Give summary of main points for Autosomal Dominant

Question 41

1. More males than females are affected
2. Affected sons are usually born to unaffected mothers; thus, the trait skip generations
3. A carrier (heterozygous) mother produces approximately ½ affected sons
4. Is never passed from father to son
5. All daughters of affected fathers are carriers

Answer 41

Give summary for X-linked recessive

Question 42

1. Both males and females are affected; often more females than males are affected
2. Does not skip generations. Affected sons must have an affected mother; affected daughters must have either an affected mother or affected father
3. Affected fathers will pass that trait to their daughters
4. Affected mothers (if heterozygous) will pass the trait on to ½ of their sons and ½ of their daughters

Answer 42

Give summary for X-Linked Dominant

Question 43

1. Only males are affected
2. Is passed from father to ALL SONS
3. Does not skip generation

Answer 43

Give summary for Y linked