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Flashcards in Genetics Basis/Muts/Path Deck (50)
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1

3 Positions of Centromere

Metacentric
Submetacentric
Acrocentric

2

Pseudoautosomal Pairs (PARs)

X and Y share 2 regions of homology which undergo high levels of recombination

3

XIST

Gene only expressed on inactive X to cause inactivation

4

Lyon Hypothesis (3)

In female somatic cells, X inactivation occurs early, is random, and is clonal

5

Unbalanced or "Skewed" X Inactivation

When mutation of X linked disorder is on active X and normal allele on inactivated X, so a female carrier of X linked disorder can present with it

6

Prophase I

Time of recombination/crossing over

7

3 Types of Mutations

Numerical chromosome abnormalities
Structural Chromosome Abnormalities
Gene mutations

8

2 Kinds of Aneuploidy

Trisomy 21: 47 chroms, Down syndrome
Monosomy X: 45 chroms, Turner syndrome

9

Unbalanced Structural Abnormalities

Extra or missing chromosome portions can lead to a clinical phenotype

10

Balanced Structural Abnormalities

Misplaced chromosome portions not associated w/ clinical phenotype

11

Robertsonian Translocation

Occurs to combine acrocentric chromosomes, karyotype is 45 and progeny may have Down syndrome

12

Di/polygenic

Disease that is caused by the combined effect of mutations in two/multiple genes

13

Epigenetic Factors

Hereditary factors that are independent of actual DNA sequence

14

5 Mechs of Imprinting-Related Disorders

Microdeletion w/ loss of nonimprinted gene copy
Uniparental disomy (UPD) - 2 homologous chroms from same parent
Mut in the nonimprinted copy of gene
Mut affecting the imprinting control region
Imbalance bw maternally and paternally imprinted genes that have an antagonistic effect

15

Important Result from Imprinting

***Have to inherit 1/2 of chromosomes from mom and 1/2 from dad

16

Pharmacogenetics

Study of the impact of single genetic variants on drug metabolism/action

17

Pharmacogenomics

Study of drug metabolism in relation to the whole genome or individual's overall genetic constitution

18

Pharacokinetics

Representation of body's action on the drug

19

Pharmacodynamics

Effect the drug has on the body

20

Therapeutic Window

Drug dosage that can treat disease effectively while staying in safety range

21

2 Phases of Drug Metabolism/Elimination

I: Modification of chemical, usually rendering it more polar so it can be assessed by subsequent enzymes
II: attachment of polar, ionizable group to the respected molecule (usually so it can be secreted)

22

Cytochrome P450 (4)

Monooxygenase in microsomes (vesicles made from ER membranes) that often metabolize drugs and account for genetic variation causing individual variation to many medications

23

Warfarin (4)

Anticoagulant with wide range of dosage whose effect depends on a cytP450 and an enzyme involved in clotting factor pathway

24

Malignant Hyperthermia (4)

AD
Mutations in ryanodine R and calcium channel that lowers threshold for muscles to fire spontaneously, and anesthesia further lowers this level causing them to fire

25

Pseudocholinesterase Variants

Defective variants of enzyme that breaks down muscle relaxants like succinylcholine, causing apnea that lasts for hours

26

G6P Dehydrogenase Deficiency (3)

X linked so mainly affects males, reduced capacity to fight free radicals and get hemolytic crises

27

Acute Intermittent Porphyria (3)

Autosomal dominant deficiency in enzyme in pathway for heme production - cyt p450 activating drugs like barbituates trigger

28

4 Risk Factors for Dizygotic Twins

Ethnic background of mother
Maternal age
Reproductive medicine techniques
Undetermined genetic factors

29

Twin-Twin Transfusion Syndrome

In monochorionic pregnancies only, one fetus transfuses blood into other twin, resutling in anemia, intrauterine growth retardation, and death in donor

30

Conjoined Twins

Monozygotic twins whose failed separation results from twinning process initiating approximately 13 to 14 days after fertilization

31

Turner Syndrome

Female w/ 1 X so no Barr bodies

32

Fragile X Syndrome (3)

XLR so mainly in boys
Causes autism
From trinucleotide repeats

33

Myotonic Dystrophy

Trinucleotide disease that presents earlier/more severely w/ more repeats

34

Phenylketouria (4)

AR mutation of impaired phenylalanine hydroxylase activity, causing intellectual disability and seizures and others

35

Pleiotropy

Different mutations in same gene can be responsible for development of different disorders

36

Genetic Heterogeneity

Same disorder can be triggered by muts in different genes

37

Osteogenesis Imperfecta (3)

Dominant negative mutation
2 Types: Type I (mild) collagen degraded after formed
Type II: (severe) mutated procollagen

38

Prader Willi Syndrome (cause + 4 symptoms)

From lack of paternal gene, causes hypotonia, feeding problems, truncal obesity, hypogonadism

39

Angelman Syndrome (cause + 4 symptoms)

From lack of maternal gene, causes severe ID, epilepsy, inappropriate laughter, ataxia

40

Pallister-Killian Syndrome

Potentially lethal disorder w/ major visceral anomalies, pigmented skin, facial dysmorphism

41

Incontinentia Pigmenti

XLD that affects ectodermal derivatives like skin/hair/teeth/nails/eyes/brain

42

Neurofibromatosis (3)

Autosomal dominant disease w/ variable expressivity, can have just small lumps on skin or large internal/external plaque things

43

Ectrodactyly (3)

Autosomal dominant split hand deformity w/ reduced penetrance

44

Familial Testotoxicosis/Precocious Puberty

Male-limited autosomal dominant disorder

45

Retinitis Pigmentosa

Dramatic locus heterogeneity that can cause progressive/peripheral visual loss and poor dark vision

46

Pyloric Stenosis

Multifactorial disease w/ sex bias, 5:1 more common in males

47

Cystic Fibrosis

AR disorder w/ respiratory and bowel problems, as well as male infertility

48

Waardenburg Syndrome

AD problem causing hearing loss among other things

49

Duchenne Muscular Dystrophy

XLR disease causing muscular development problems, resorting to Gower's maneuver to stand

50

Van der Woude Syndrome (4)

Autosomal dominance w/ reduced penetrance and variable expressivity
Can cause lip pits in mild or cleft lip in severe