(DA) Genetic Basis of Disease

Question 1

This or That? For each disease or disorder, click on the correct inheritance pattern or chromosomal alteration.

Cystic fibrosis
Autosomal Dominant

Autosomal Recessive

Answer 1

Autosomal Recessive

Correct.
Cystic fibrosis is an autosomal recessive disorder thus two copies of the gene are needed for expression. In cystic fibrosis, disruption in chloride channels results in chronic cough, upper respiratory infections, and difficulty removing airway mucus. Pancreatic secretions and digestion are also affected.

Question 2

This or That? For each disease or disorder, click on the correct inheritance pattern or chromosomal alteration.

Familial hypercholesterolemia

Autosomal Dominant

Autosomal Recessive

Answer 2

Autosomal Dominant

Familial hypercholesterolemia is inherited in an autosomal dominant pattern. One copy of the gene is needed for expression. In this disease, a lack of receptors for low-density lipoprotein (LDL) cholesterol results in significant hyperlipidemia.

Question 3

This or That?

Ehlers-Danlos syndrome

Autosomal Inheritance

Aneuploidy

Answer 3

Autosomal Inheritance

Ehlers-Danlos syndrome is group of disorders that are a result of autosomal inheritance, meaning the genetic disruption is found on chromosome pairs 1 to 22, rather than the sex chromosomes. Aneuploidy would indicate a change in chromosomal number or translocation of chromosomes. Ehlers-Danlos syndrome involves highly elastic skin, hypermobile joints, and abnormalities in collagen production.

Question 4

This or That?

Turner syndrome

Autosomal Inheritance Disorder

Aneuploidy

Answer 4

Aneuploidy

Turner syndrome develops from an abnormal number of chromosomes in a female. Aneuploidy refers to an abnormal number of chromosomes. In Turner syndrome, the autosomal chromosomes are not affected. Turner syndrome results from a missing XO chromosome, presenting as 45, XO. Severity of the disease varies. Amenorrhea, infertility and short stature may occur.

Question 5

This or That? For each disease or disorder, click on the correct inheritance pattern or chromosomal alteration.

Niemann-Pick disease

Autosomal Dominant

Autosomal Recessive

Answer 5

Autosomal Recessive

Niemann-Pick disease is an autosomal recessive inherited disorder, meaning two copies of the gene must be inherited for expression. It affects lysosomal storage, and involves accumulation of sphingomyelin in cells of the brain, spleen, and liver.

Question 6

This or That?

Wilson disease

Autosomal Inheritance

Aneuploidy

Answer 6

Autosomal Inheritance

Wilson disease is an autosomal recessive inherited disease. Wilson disease does not develop from abnormalities in chromosome number, which is called aneuploidy. Wilson disease affects copper metabolism and results in excess copper deposits in liver and brain.

Question 7

This or That?

Huntington disease

Autosomal Dominant

Autosomal Recessive

Answer 7

Autosomal Dominant

Huntington disease is an autosomal dominant inherited disorder. One copy of the gene is needed for expression. The signs and symptoms of Huntington disease do not develop until adulthood. It involves movement (spasticity) and cognitive function.

Question 8

This or That?
Klinefelter syndrome

Autosomal Inheritance

Aneuploidy

Answer 8

Aneuploidy
Klinefelter syndrome is results from a chromosomal alteration involving an XXY inheritance pattern. Men with Klinefelter syndrome often experience lack of development of testes, gynecomastia, and cognitive development impairments.

Question 9

This or That? For each disease or disorder, click on the correct inheritance pattern or chromosomal alteration.

Down syndrome
Autosomal Dominant

Aneuploidy

Answer 9

Aneuploidy

Down syndrome is a result of chromosomal alteration, trisomy 21. This means there is an additional copy of chromosome 21, resulting in aneuploidy, an abnormal number of chromosomes.

Question 10

This or That?

Marfan syndrome

Autosomal Dominant

Autosomal Recessive

Answer 10

Autosomal Dominant

Marfan syndrome is an autosomal dominant inherited connective tissue disorder. Only one copy of the gene is needed for expression of this disorders. Marfan syndrome affects fibrillin formation. Aorta and heart valve structures are commonly affected. Individuals often have tall stature and hypermobility of joints.

Question 11

This or That?

Familial adenomatous polyposis

Autosomal Dominant

Autosomal Recessive

Answer 11

Autosomal Dominant
Familial adenomatous polyposis is an autosomal dominant inherited disorder that leads to early onset of hundreds of polyps throughout the colon. Familial adenomatous polyposis has been linked to increased risk of colon cancer.

Question 12

Question 1 of 5

If a genetic mutation occurs on one of the first 22 pairs of chromosomes and only one copy of the gene is needed for expression, what type of genetic defect is present?

“X-linked” recessive
Autosomal dominant
“X-linked” dominant
Autosomal recessive

Answer 12

Autosomal dominant

Question 13

Question 2 of 5

An autosomal dominant disease, which affects the connective tissue of the heart valves, aorta, and joints and causes tall stature, is _________________________.

Marfan syndrome
Familial adenomatous polyposis
Huntington disease
Cystic fibrosis

Answer 13

Marfan syndrome

Question 14

Question 3 of 5
What is aneuploidy?

A picture for analysis of chromosomes
A single genetic mutation
A change in the number or structure of chromosomes
A genetic mutation in two genes

Answer 14

A change in the number or structure of chromosomes

Question 15

Question 4 of 5

Identify which chromosome is affected in Down syndrome.

Chromosome 15
X chromosome
Chromosome 21
Y chromosome

Answer 15

Chromosome 21

Question 16

Question 5 of 5

Klinefelter syndrome results from an extra X chromosome in males. How would this appear on a karyotype?

XYY
XO
XXX
XXY

Answer 16

XXY