Patterns of Inheritance (Part 1) Flashcards Preview

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Flashcards in Patterns of Inheritance (Part 1) Deck (18):
1

Define Gene:

Sequence of DNA that codes for a protein, including regulatory regions

2

Define locus:

Location of gene on chromosome

3

Define allele

Different forms (versions) of a gene

4

Define polymorphism:

Multiple forms (alleles) of a gene in population

5

Define homozygote:

Possess same allele at a locus

6

Define heterozygote:

Possess different alleles at a locus

7

Define Dominant

Require only one copy of the mutation to produce disease

8

Define recessive

Requires TWO copies of the mutation to produce disease

9

An allele is one of the alternate forms of a gene that occur at a ___.

Locus

10

Define recurrence risk

Probability of the offspring of a couple will express the genetic disease.

- For single gene disorders, it does not depend on the number of previously affected/ unaffected offspring.

11

Recurrence risk depends on what?

Mode of inheritance of a disease

12

Define proband:

The AFFECTED INDIVIDUAL in the family who has approached the physician for consultation.

13

Define monozygotic twins

-Arise as a result of fertilization of a single zygote.

-Possess identical genes

14

Define dizigotic twins

-Arise as a result of fertilization of two ova

-Genetically share about 50% genes (sibling)

15

Autosomal dominant disorders manifest in which state?

Heterozygous

16

What are the characteristics of Autosomal Dominant disorders when looking at pedigree?

- Affected children receive disease causing gene from affected parent.

- Skipped generations NOT common (Vertical inheritance)

- Males and females are affected with equal frequency

- Male to male transmission is seen

17

How is the affected parent depicted as for autosomal dominant disorder? Normal parents?

Affected parent: Aa

Normal parent: aa

18

For a autosomal dominant disorder, if children have one affected parents, and one normal parent, what is the recurrence risk?

50% risk to the next offspring regardless of the sex of the child.

(Note: Recurrence risk does NOT depend on the number of previously affected children. It remains the same for every new child born to the couple... 50%)