Genetic Basis for disease

Question 1

What is genetics

Answer 1

study of hereditary, focused on single gene (develop treatment plans)

Question 2

What is a gene?

Answer 2

unit of heredity
- sequence of nucleotides
- determines structure or has regulatory function in a cell

Question 3

Chromosomes?

Answer 3

Linear arrangement of genes within the cell nucleus
- normal = 23 pairs
22 paurs of autosomes and 1 sex chromosome XX or XY

Question 4

Homozygous vs. heterozygous

Answer 4

homo = processing pair of identical genes
hetero= different genes on a pair of chromosomes

Question 5

What is genomics?

Answer 5

study of all genes, genetic inter-relationship and their influence on growth and development

Question 6

What is congenital disorder?

Answer 6

abnormalities of a body structure, function, or metabolism & present at birth
1. Chromosomal disorder
2. Single gene disorder
3. Multifactorial disorder

Question 7

If someone has a numerical disorders what does that mean?

Answer 7

(number of chromosomes) loss of chromosome = more serious (death)

Question 8

euploidy

Answer 8

normal number of chromosomes

Question 9

Aneuploidy

Answer 9

abnormal cells do not contain chromosomes in multiples of 23

Question 10

What is the cause of Aneuploidy?

Answer 10

nondisjunction (abnormal in daughter cells)
- Failure of chromatid pairs to separate
- Results in unequal number of chromosomes in daughter cell

Question 11

What are the 2 types of aneuploidy?

Answer 11

1. autosomal (abnormal of chromosomes in a somatic cell 13, 18, 21
   - Trisomy = when a cell contains one extra copy of any the chromosomes
2. Monosomy (when a cell only contains only 1 copy of any of the chromosomes instead of 2 (loss of chromosomes)) LEATHAL

Question 12

What is an example of autosomal genetic disorder?

Answer 12

down syndrome
- facial abnormalities
- intellectual disability/low IQ, poor muscle tone, short stature, systemic disorders, mortality
- Increased risk with increased maternal age

Question 13

What are the 2 examples of sex chromosome disorder?

Answer 13

klinefelter syndrome and turner syndrome

Question 14

what is Klinefelter Syndrome? clinical manifestations?

Answer 14

at least 2 XX and one Y
- male appearance but female features, moderate IQ

Question 15

What is turner syndrome? clinical manidestations?

Answer 15

x chromosome monosomy = only females with only 1 X chromosomes
- webbed neck, shield like chest, faulty ovary development, short stature, narrow aorta, some IQ impairment

Question 16

What is polyploidy?

Answer 16

• more that 2 complete sets of chromosomes
  child will die
  tetraploidy - 92 chromosomes
  triploidy - 69 chromosomes

Question 17

tetraploidy vs. triploidy

Answer 17

tetraploidy - 92 chromosomes
triploidy - 69 chromosomes

Question 18

What are some structural disorders?

Answer 18

Deletions
Duplication
Inversion
Translocation
Fragile sites

Question 19

Deletions example of disorder?

Answer 19

loss of portion of a chromosome
- Cri Du Chat Syndrome = low birth weight, microcephaly, heat heart defects, intellectual disability

Question 20

Duplication

Answer 20

presence of a repeated gene or gene sequence

Question 21

Inversion

Answer 21

reversal of gene order - entire or just portion

Question 22

Translocation

Answer 22

transfer of one part of a chromosome to another

Question 23

Fragile sites example ?

Answer 23

chromosome parts that develop distinctive breaks and gaps
- fragile X syndrome: only effects X chromosome (only in males)
2nd most common genetic disorder

Question 24

What are the 2 branches off of chromosomal disorder?

Answer 24

1. numerical disorder
2. structural disorder

Question 25

What are the 3 branches off of Single gene disorders?

Answer 25

1. autosomal dominant 2. autosomal recessive 3. sex chromosomes

Question 26

Autosomal dominant? example?

Answer 26

abnormal gene is dominant and normal gene is recessive Marfan’s Syndrome: connective tissue disorder involving skeletal, ocular, and cardiovascular systems - Thin tall arm span is longer than there height – life threatening later in life because of their weakened aorta

Question 27

Autosomal Recessive? example?

Answer 27

abnormal gene is recessive and normal gene is dominate - Phenylketonuria (PKU) part of newborn screening - Cystic Fibrosis

Question 28

What is PKU?

Answer 28

Phenylketonuria Inability of body to convert phenylalanine to tyrosine = elevated levels of phenylalanine (toxic to cns) & deficient tyrosine - Accumulation in the blood and excess causes alterations in nervous system development Metabolic system disturbances - Tests now available for detection = tests for autism, seizure disorders

Question 28

What is PKU?

Answer 28

Phenylketonuria Inability of body to convert phenylalanine to tyrosine = elevated levels of phenylalanine (toxic to cns) & deficient tyrosine - Accumulation in the blood and excess causes alterations in nervous system development Metabolic system disturbances - Tests now available for detection = tests for autism, seizure disorders

Question 29

Sex chromosome disorders in single gene disorders? example?

Answer 29

most x link recessive - more in males b/c it take 2 copies for female - Duchenne Muscular Dystrophy - Fragile X Syndrome

Question 30

What is the difference between sex limited and sex influenced?

Answer 30

Sex limited - trait only occurs in 1 gender = testicular defects ... uterine defects Sex influenced = trait only occurs more often in one gender than the other = breast cancer, balding

Question 31

What is multifactorial genetic disorder?

Answer 31

Interaction between genetic susceptibility and environment (living environment) - more frequently in females

Question 32

What are some multifactorial genetic examples

Answer 32

Examples cleft lip and palate, neural tube defects, club feet, some congenital heart defects, diabetes mellitus, hypertension, some types of cancer

Question 33

What is a teratogen? examples?

Answer 33

Enviormental problems that could harm there baby - medication, smoking, drugs and alcohol, mothers health, radiation, malnutrition, micoorganisms

Question 34

What is TORCH?

Answer 34

panel of tests based on living conditions for baby - Toxoplasmosis - other - Rubella - cytomegalovirus - herpes

Question 35

What is Toxoplasmosis

Answer 35

from cat pee, undercooked meat, unpasteurized milk - Eye infections and intellectual disability and miscarriage

Question 36

rubella?

Answer 36

baby will be still born

Question 37

what is cytomegalovirus?

Answer 37

transmitted though body secretions (milk) - Death, intellectual disability

Question 38

Herpes

Answer 38

Herpes – can be spread during birth STI

Question 39

What is the outcome of a terogen?

Answer 39

congenital defects

Question 40

what is a recurrence risk?

Answer 40

probability of an individual will develop a genetic disease

Question 41

What would be the transmission rate in autosomal dominant for an affected parent and normal parent?

Answer 41

50%risk

Question 42

What would be the transmission rate in autosomal dominant for an affected parent and an affected parent

Answer 42

75% risk

Question 43

What would be the transmission rate in autosomal recessive for an heterozygous parent and heterozygous parent =

Answer 43

25% risk

Question 44

What would be the transmission rate in autosomal recessive for an heterozygous parent and affected parent =

Answer 44

50% risk

Question 45

Can there be a genetic disorder in a child whos parents do not carry the gene?

Answer 45

yes even tho there is no history of disease in family there could a a probable new mutation in a parents genes