Macri Genetics Exam 1

Front 1

Concordance and Discorcordance

Back 1

When two individuals in a family have the same disease they are called concordant for the disorder
If they do not have the same condition (IDDM, MI) they are said to be discordant

Front 2

How are multifactorial traits studied? (4)

Back 2

Empiric risk determination
Heritability
Adoptive/Twin studies
Association studies

Front 3

Birth Defects with MF inheritance (5) and which one is most common? What is the % recurrence risk associated?

Back 3

Cleft lip/cleft palate

Neural tube defects – open spina bifida and anencephaly (1/1000)

Pyloric stenosis

Congenital heart malformation - most common birth defect with MF inheritance

3-5% recurrence risk if a couple has had a child with congenital malformation with MF inheritance


Club foot

Front 4

Balanced chromosome rearrangement means what in terms of phenotypic effect?

Back 4

no phenotypic effect.

Front 5

Polyploidy

Back 5

results of two sperm fertilize one egg or haploid sperm fertilizes diploid egg.

Polyploidy is the condition of some biological cells and organisms manifested by the presence of more than two homologous sets of chromosomes. Polyploid types are termed according to the number of chromosome sets in the nucleus: triploid (three sets; 3x), tetraploid (four sets; 4x), pentaploid (five sets; 5x), hexaploid (six sets; 6x) and so on.

Front 6

Phenotype of Down's Syndrome

Back 6

Trisomy 21
Characteristics: epicanthal folds, brachycephaly, flat nasal bridge, low-set ears, short, broad hands with transverse palmar crease, mental retardation, early-Alzheimer’s, congenital heart septal defects.

Front 7

Klinefelter Syndrome

Back 7

47, XXY

Looks like a eunuchoid body with a lack of male secondary sex characteristics, hypogonadism, testicular atrophy. 1 in 2,000.

Front 8

Turner’s Syndrome

Back 8

45,X0 AKA Monosomy X

Short stature, webbed neck, shield chest. Primary amenorrhea, infertility, narrowed aorta, 1 in 6,000 female births.

Front 9

XYY syndrome

Back 9

Excessively tall with severe acne. 1 in 1,000 males. Increased risk of behavioral problems.

Front 10

Edward's Syndrome

Back 10

Trisomy 18

Growth retardation in uterus, mental retardation short sternum, small pelvis, rocker-bottom feet, cardiac, renal and intestinal deficits.

Front 11

Patau’s syndrome

Back 11

Trisomy 13

Choroid plexus cysts. Cleft lip, palate, cardiac dextroposition and septal deficits. Overlapping fingers. 1/2500 births.

Front 12

Cri du Chat babies - phenotype and what type of mutation

Back 12

deletion

dysmorphic facial features

Front 13

FISh detects what type of mutations

Back 13

translocations, which may be balanced (no phenotypic effect b/c no loss of genetic material) or unbalanced

Front 14

in philadelphia chrom, gene movement causes...

Back 14

overexpression (9:22)

Front 15

robertsonian translocation, what happens

Back 15

q arm is lost so p arms stick together

Front 16

which 3 monosomy's are lethal?

Back 16

13, 14, 21

Front 17

why is translocation important historically?

Back 17

they helped change monkey chr's to human ones during evolution

Front 18

what is an Oncogene

Back 18

Mutant allele of a proto-oncogene, a class of normal cellular protein-coding genes that promote growth and survival of cells

Front 19

Gatekeeper TSGs - what do they do?

Back 19

Control Cell Growth

Gatekeeper genes:
-block tumor development by regulating the progression of cells through the checkpoints (“gates”) in the cell cycle
-Or by promoting programmed cell death and thereby controlling cell division and cell survival
-they also look for and repair mutations

Gatekeeper TSGs encode:
Regulators of various cell-cycle checkpoints
Mediators of programmed cell death

Front 20

Caretaker TSGs - what do they do?

Back 20

Protect the integrity of the genome:
Loss of function of caretaker TSGs permits mutations to accumulate in oncogenes and gatekeeper genes, which in cancer, go on to initiate and promote cancer

Caretaker TSGs encode proteins:
responsible for detecting & repairing mutations
Involved in normal chromosomal disjunction
Of components of programmed cell death

Front 21

Cancer Etiology (2)

Back 21

Hereditary cancer syndromes
Initial cancer-causing mutation is inherited through the germline
Is already present in every cell of the body

Sporadic
Most cancers, however, are sporadic
Mutations occur in a single somatic cell (SOMATIC MUTATION), which then divides and proceeds to develop into cancer

Front 22

Tumor Initiation

Back 22

Different types of genetic alterations are responsible for initiating cancer, such as:
-Activating or gain-of-function mutations, including gene amplification, point mutations, and promoter mutations that turn one allele of a proto-oncogene into an oncogene
-Chromosome translocations that cause mis-expression of genes or create chimeric genes encoding novel proteins

Front 23

RET in Hirschprung’s disease is a what type of mutation

Back 23

loss-of-function mutation

Front 24

RET in MEN2A and MEN2B are what types of mutation

Back 24

specific point mutations

Front 25

Inherited defects that alter function of repair enzymes lead to dramatic increase in frequency of mutations (4)

Back 25

Xeroderma pigmentosum
Ataxia-telangiectasia (AT)
Fanconi anemia
Bloom syndrome

associated with caretaker tsg's dysfunction

Front 26

Factors which affect alleles in populations (3)

Back 26

Founder Effect
Genetic drift
Selection

Front 27

Founder effect

Back 27

Nonrandom distribution of alleles among the individuals who founded particular subpopulations
Islands
Small towns in isolated areas
Groups such as Ashkenazic Jews, French Canadians, Amish, Mennonites

Front 28

Genetic Drift

Back 28

Fluctuations in the frequency of alleles resulting from chance occurrences operating in small populations

Front 29

Selection

Back 29

Selection of favorable mutations in response to environmental conditions