Principles of Genetic Inheritance

Question 1

What is Lyonization?

Answer 1

X chromosome inactivation at random.

Question 2

What is Mosaicism?

Answer 2

A condition in which cells from a patient have different genotypes and karyotypes: Down Syndrome, Klinefelter Syndrome, Turner Syndrome.

Question 3

Klinefelter Syndrome

Answer 3

47XXy

Question 4

Turner Syndrome

Answer 4

45XO(lacking a X chromosome)

Question 5

Patau Syndrome

Answer 5

47XX, +13. Most perinatal death within 1 week.

Question 6

Edwards Sydnrome

Answer 6

47XX, +18. Most perinatal death within 1 year.

Question 7

In which cells are epigenetic imprints reseted every generation?

Answer 7

Germ cells

Question 8

What is Prader-Willie Syndrome?

Answer 8

deletion on chromosome 15 of the paternal PWS region ( which is the active region)

Question 9

What is Angelman Syndrome?

Answer 9

deletion on chromosome 15 of the maternal AS Region (which is the active region).

Question 10

What is Uniparental Disomy?

Answer 10

Related to Non-disjunction and Genomic Imprinting. 2 chromosomes are inherited from the same parent, therefore they will have parent specific imprinting.

Question 11

How is mitochondrial DNA different?

Answer 11

replication takes place in the mitochondria, contains no introns, inherited exclusively through the maternal line, lack of DNA repair mechanism, mutation rate 10X higher than nDNA.

Question 12

What is Leber’s hereditary optic neuropathy(LHON)?

Answer 12

Mitochondrial Disorder:Degerneration of retinal ganglion cells.

Question 13

What is MELAS(Mitochondrial Encephalomyopathy, lactic acidosis, and stroke-like episodes?

Answer 13

Mitochondrial Disorder: Stroke and Dementia, Lactic Acidosis, affects brain and nervous system.