Patterns Of Inheritance

Question 1

Genotype

Answer 1

Combo of genes at one locus on both chromosomes

Question 2

Haplotype

Answer 2

Set of genes on neighboring loci on ONE chromosome

Question 3

Phenotype

Answer 3

Outward manifestation of genotype

Question 4

Compound heterozygote

Answer 4

Two different mutant alleles are present

Question 5

Single gene disorder

Answer 5

Determined by alleles at one locus

Question 6

Pleiotropic

Answer 6

A single abnormal gene can produce a wide variety of phenotypes

Question 7

______ are disproportionately affected by single gene disorders

Answer 7

Children

Question 8

Penetrance

Answer 8

Probability that a mutant genotype will produce an abnormal phenotype

Question 9

Expressivity

Answer 9

Severity of the phenotypic manifestation of a disease genotype

Question 10

Variable expressivity

Answer 10

Severity of disease differs in individuals with same genotype

Question 11

Definition and synonyms for proband

Answer 11

Affected individual that initiates genetic consultation

Also called propositus or index case

Question 12

Consultand

Answer 12

Person who brings family to the attention of a geneticist

Question 13

Family of siblings is called

Answer 13

Sibship

Question 14

Consanguineous

Answer 14

Couples with common ancestors

Question 15

A genetic case is _______ if the proband is the only affected family member

Answer 15

Isolated

Question 16

A genetic case is ______ if the isolated case is due to a new mutation

Answer 16

Sporadic

Question 17

Patterns of inheritance shown by single gene disorders depend on these two factors

Answer 17

1. Chromosomal location

2. Dominant or recessive phenotype

Question 18

Autosomal recessive inheritance generally results in a _______ mutation

Answer 18

Loss-of-function

Question 19

Most common ARD

Answer 19

Cystic fibrosis

Question 20

Autosomal dominant inheritance comprises more than _____ of all Mendelian disorders

Answer 20

50%

Question 21

Sex limited phenotype

Answer 21

Autosomal inherited but expressed only in one sex

Question 22

X-linked dominant inheritance can be tracked by lack of _______ ________

Answer 22

Male-to-male transmission

Question 23

Pseudoautosomal inheritance

Answer 23

Recombination between two homologous X chromosomes in females or between contiguous loci in X and Y chromosomes in males - can cause X-linked traits to appear autosomal

Question 24

Mosaicism

Answer 24

Presence of two cell lineages that differ genetically but are derived from a single zygote

Question 25

Allelic heterogeneity

Answer 25

different mutations in the same gene may produce the same phenotype

Question 26

Locus heterogeneity

Answer 26

Mutations in different genes may cause the same phenotype

Question 27

Clinical/phenotypic heterogeneity

Answer 27

Different mutations in the same gene may cause different phenotypes

Question 28

Founder effect

Answer 28

Genetic drift that occurs when a sub population is isolated

Question 29

Gene flow

Answer 29

Slow diffusion of genes across a barrier as in migration

Question 30

Genetic admixture

Answer 30

Migrant populations’ characteristic allele frequencies merge with the new population