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1

how do you figure out an incest child having the disease?

pathway tracingg

2

what is pathway tracing?

following the allele away from the known location and moving away from the reference point and toward the point in question

3

what is a primary relative?

immediate relative (just one position away along a descent line)

4

what is a secondary relative?

slightly removed ( two positions away)

5

what is a tertiary relative?

more distant relative (3 positions away)

6

are there fourth degree relatives?

yes, but we donメt go out that far

7

def of multifactorial inheritance

genetics is due to many factors, some genetic some not

8

two fundamental forms of multifactorial inheritance?

multiple genes determine trait (polygenic inheritance), and a single gene and enviromental factors

9

what are the early cases of multifactorial inheritance?

penetrance, variable expressivity

10

what is the example of polygenic inheritance used?

wheat grain color

11

what do you begin to see if one begins to put the phenotypes on a graph?

normal distribution (bell curve)

12

what color of wheat is most common?

pink (amber as he says it)

13

what else seems to work in the same way as wheat color?

human skin color

14

what determines the higher continuous variation?

the greater the number of genes involved in the polygenic system

15

what happens if you add in chances for additional enviromental variables to a polygenic system?

the variation becomes very smooth and continuous, and therefore it becomes very difficult to dissect out the genetic component

16

what is the genetics of obesity?

complex multifactorial trait

17

what are the factors of obesity?

a trait where you wont get saitity, and the enviromental is where you over eat and not exercise

18

what is the genetics of intelligence?

complex multifactorial trait

19

what did the Bach pedigree look like?

it LOOKED like musical genius was a autosominal dominant trait

20

is the use of a pedigree a good way to be used as convincing evidence for a complex mulifactorial trait?

it may be problematic

21

what should you use instead?

comparing specific genotypes placed in differing or same enviroments

22

what is an example of genotypes living in different enviroments?

monozygous twins that have lived in different enviroments

23

what are the results of the monozygous twin studies?

the twins yeild substantial evidence for a GENETIC basis to intelligence

24

what university has an ongoing monozygous twin study?

university of minnesota

25

what is the final conclusion of the twin studies?

merely confirm that both genetic and enviromental factors are important, although many would argue that its evidence for genetic factors

26

what is another way to approach mulitfactorial inheritence? (other than pedigree or genetic cohort)

heritability

27

def of heritability

an estimate of the population phenotypic VARIATION that is due to genotype

28

another def of heritabilityナ.

the fraction of the phenotypic variability in the population which is determined entirely by genotype

29

heritability = 1

the population phenotypic variance is likely due entirely to genotype

30

heritability = 0

the population phenotypic variance is likely due entirely to enviroment

31

what does heritability a measure of?

correlation between genotype and phenotype

32

what does inheritance tell us?

the HOW of a trait

33

what does heritability tell us?

how MUCH (genetic predisposition)

34

how is heritability looked at in the final analysis?

abstraction of limited value for routine inheritance prediction or understanding specific genetic factors

35

what is the newest way to approach multifactorial inheritance?

find the correlation b/t some specific DNA marker sequence found in 2 populations, one with trait one w/o

36

what have single nucleotide polymorphisms done?

proven to be helpful to identify genes for a susceptibility to the development of a disease

37

what are empirical risk figures?

a gathering of observational studies that might be used to predict the future based on the past

38

what do empirical risk figures give you?

only provide data based on similar prior situations, not anything b/t genetic or enviromental

39

what are the common ways to approach multifactorial inheritance?

pedigrees, twin studies, heritability, DNA associated studies, empirical risk tables

40

pro/ con pedigree

attemping to model the disease- but not good except for finding broad patterns

41

pro/con twin studies

difficult to use in practical way

42

pro/con heritability

complex mathematical derivation and of limited practical use

43

pro/con DNA associated studies

requiring difficult laboratory testing and only susceptibilities

44

pro/con empirical risk table

requires large statistical databases and do not explain mechanisms

45

familial risk compared to gen pub?

considerably higher

46

familial risk over generations?

drops sharply with increasing distance to index case

47

what is the risk of a first degree relative?

roughly a square root of the population risk

48

what is higher when more than one family member is affected?

recurrent risk

49

what are the two basic ways to look at human multifactorial traits?

1)model the disease 2)develop empirical risk figures

50

how do you model the human multifactorial trait?

look for a basic pattern of inheritance using a pedigree, then develop rules, as needed, for deviation from simple predictions

51

how do you use the empirical risk figures to look at a human multifactorial trait?

rely on PRIOR OBSERVATIONS to est statistical tools of prediction

52

def of adolescent idiopathic scoliosis (AIS)

multifactorial condition of spinal curvature laterally >10 degrees

53

how common is AIS

1 in 30 in persons 10-16 years of age

54

how does the pedigree of AIS look?

autosomal dominant with reduced penetrance

55

what is the penetrance of AIS?

~60%

56

how do you find the penetrance of AIS?

from one parent, a simple autosomal dominant model would have to have generated a recurrent risk of 50% and yet the statistic is 29% so 0.5x0.6=0.3 so 60% penetrance

57

def of spondylolysis/ spondylolisthesis

multifactorial conditions of spinal pars interacticularis and a common source of low back pain

58

spondylolysis=

a stress fracture of the pars of the vertebral body

59

spondylolithesis=

a slippage of vertebral bodies which may happen due to spondylolsis or degenerative changes with age

60

how common are spondylolysis?

~5% of pop

61

how common are spondylolithesis?

~2.5%

62

what is the general pedigree look of spondys?

autosomal dominant with reduced penetrance

63

what is the penetrance of spondys?

~40%

64

def of congental dislocation of the hip?

(acetabular dysplasia) multifactorial anomaly characterized by displacement of the femoral head outside of acetabulum prior to birth

65

how common is hip dislocation?

1 in 1000 births

66

what model does hip dislocation follow?

autosomal dominant with reduced penetrance

67

what is the recurrence risk for sibs in congenital dislocation of the hip?

about 5%

68

what is ankylosing spondylitis?

multifactorial autoimmune "spondyloarthropathy" condition. Chronic painful progressive inflammatory arthritis primarily affecting spine and si jts

69

what antigen is ankylosing spondylitis correlated to?

HLA- B27

70

how common is AS

1 in 400

71

neural tube defects (including spina bifida)

multifactorial condition characterized as an embryonic failure to fully close the developing neural tube

72

what chomosomes are neural tube defects linked to?

17q11 and 6q27

73

how common are neural tube defects?

1 in 1000

74

what is the recurrence risk for sibs in neural tube defects?

~4%

75

pyloric stenosis?

multifactorial anomaly of substantial narrowing of the stomach pylorus, where there is hypertrophy and hyperplasia of the pylorus

76

incidence of pyloric stenosis?

1/400 m>f so SEX INFLUENCED

77

what pattern does pyloric stenosis follow?

autosomal dominant with reduced penetrance with some sort of sex influence

78

cleft lip and palate?

multifactorial anomalies with a development failure of fusion of the frontal process with the maxillary process during embryonic development

79

incidence of cleft lip/palate?

1 in 700

80

pattern does cleft lip/palate follow?

autsomal dominant with variable expressivity/ severity

81

club foot?

multifactorial collection of congenital anomalies characterized by a foot that is twisted in and down

82

what are the skeletal deformities with club foot?

TALIPES EQUINAVARUS, talipes calcaneovalgus, metatarsus varus

83

def of talepes equinavarus?

adduction of the forefoot, inversion of the heel and plantar flexion of the forefoot and ankle

84

incidence of club foot

3 in 1000

85

pedigree pattern of club foot>

autosomal dominant with reduced penetrance

86

pentrance of club foot?

40.00%

87

diabetes

multifactorial condition of abnormal glucose metabolism/ utilization characterized by hyperglycemia, due to altered insulin secretion from the pancreatic beta cells or receptivity to insulin

88

what types of diabetes are clinically similar to diabetes with hyperglycemia?

glucosuria, polyuria, and polydispsia

89

which of the two diabetes has a higher genetic link?

type 2

90

what is the sibship risk of diabetes?

~40%

91

what is the risk of a child of a parent with type 2 diabetes?

33.00%

92

hypertension?

multifactorial condition characterized by high systemic arterial blood pressure, which is a physial finding which may have many causes

93

what are the 3 genetic characteristics that all biological populations have?

1)a gene pool 2) allelic frequencies 3) genotypic and phenotypic frequencies

94

what is a gene pool?

the sum total of all the alleles in the reproductive gametes from members of a mendelian population; the raw material used to build a subsequent generations

95

what is a mendelian population?

a group of diploid, sexually interbreeding (or potentially interbreeding) individuals possessing a common gene pool

96

what does gene pool mathematical modeling require?

the hardy-weinberg equilibrium

97

what is the hardy-weinberg equilibrium?

that a pool be in a special balanced state wherein allelic frequencies remain constant

98

what are the 5 conditions that must be constant to get a H-W equilibrium

1) no mutation 2)no migration 3) no assortive mating 4) no selection 5) no genetic drift

99

what is the "A" FREQUENCY?

p

100

what is the "a" FREQUENCY?

q

101

what does p+q= ?

1 (or 100% of the variation of the gene in question)

102

what are the letters for 3 allelic forms?

p+q+r= 1

103

what are the letters for 4 allelic forms?

p+q+r+s=1

104

what are the letters for homozygous dominants (AA)

p^2

105

what are the letters for heterozygotes (Aa)

2pq

106

what are the letters for homozygous recessives (aa)

q^2

107

in a 2-allelic system, what is the formula for the frequency of genotypes in this population?

p^2 + 2pq + q^2 = 1

108

what is the formula for a 3 allelic system?

(p+q+r)^2 = 1

109

what is the formula for a 4 allelic system?

(p+q+r+s)^2 = 1

110

what are the blood types caused by?

glycosphinglolipids produding from the plasma membrane of the RBC

111

what the ABO systema an example of?

a multi-allelic gene on chromosome 9

112

what is erythroblastosis fetalis?

incompatibility b/t maternal and fetal blood leading to fetal loss

113

what is the major histocompatibility complex?

larger cluster of genes on chromosome 6 that determine whether or not transplanted tissues will be rejected

114

what does the major histocompatibiliy complex code for?

the production of human leukocyte antigen (HLA)

115

what are the functions of HLA type 1?

important on all cells in establishing one's self

116

what are the functions of HLA type 2?

know to be imporant in the presentation of foreign antigens to the immune system

117

def of haplotypes

a combination of alleles (for different genes) that are located closely together on the same chromosome and that tend to be inherited together

118

do HLA allelic formations cause disease?

particular HLA allelic forms have been correlated with particular diseases

119

what is the risk for anylosing spondylitis with people that have HLA antigen B27?

over 90 times greater than the normal population

120

what is an antibody?

a protein coded for by a gene, though it is a rather complex example of gene expression

121

what is severe combined immunodeficiency (SCID)

a collection of disorders characterized by a loss of immunoglobulin production, both t and b lymphocytes are crippled

122

what is agammaglobulinemia?

Heterozygous collection of disorders involving a lack of plasma cells and no immunoglobulin production

123

how do infectous agents gain "access" to the human body/ cells?

by having evolved to bind to specific cell surface molecules, coded for by genes

124

can some cancer types run in families?

yes

125

what is cancer ultimately a disease of?

genes

126

what are proto-oncogenes?

promote cell division in many forms

127

what are the forms that proto-oncogenes can promote cell division?

1)growth hormone r/c 2) G- protein transducers 3) transcription promoters

128

what are the mutated proto-oncogenes called?

oncogenes

129

what do oncogenes do?

promote uncontrolled cell division

130

what are most ongenic mutations considered as?

dominant (bacause a single copy being inappropriately switched on will create a problem)

131

what is burkitts lymphoma?

rare cx of the lymph organs most often due to a TRANSLOCATION b/t chromosomes 8 and 14

132

what is chronic myelogenous leukemia?

rare cx, though a common form of leukemia that is due to TRANSLOCATION b/t chromosomes 9 and 22

133

what is the Philedelphia chromosome?

translocation of 9 and 22

134

what are tumor suppressor genes?

inhibit cell division

135

what are the best described tumor suppressor genes?

Rb for retinoblastoma; BRCA1 and p53

136

how common is p53?

active in ~50% of all cx

137

what was the gene on the year in 1995?

p53

138

where is p53 found?

chromosome 17

139

what does the knudson hypothesis state?

carcinogenesis requires multiple mutations

140

what is kundsons other model?

the two hit model

141

what is the two hit model?

a model that may explain many cxs that mainly involve tumor-suppressor genes

142

what needs to happen in the two step model?

1)both copies of a tumor-suppressor need to be mutated (sporadic cx) 2) if only one mutant gene is inherited, then it would only take a single hit to lose tumor-suppression (familial cx)

143

what makes the cx cell exceed the normal number of mitotic cycles?

activation of the gene for telomerase seems to make this possible

144

what is the function of telomerase?

enzyme lengthens the chromosomal telomeres

145

how are most cxs classified as? Classically inherited or not?

most are not classically inherited (sporatic) but some can be considered classic

146

what type (sporatic or classic) are most breast and colon cxs?

most are sporatic (hereditary makes up 5%)

147

a person with BRCA1 or 2 have what risk of getting breast cx?

~60-80% risk

148

carcinogenesis requires what?

multiple damages to cell cycle controlling genes

149

what ways can oncogenes cause cx?

1)direct mutation 2) virus promotion (15%) 3) chromosome rearragement

150

what ways can switching off tumor-suppressor gene cause cx?

direct mutation

151

why is cx a multifactorial condition?

because there are genes and enviromental agents involved as well as cx is a collection of diseases, there is no simple risk assessment for all forms

152

how many base pairs does mitochondria have?

~17000 base pairs which codes for 40 genes

153

what makes the mitochondria cx predictions so difficult?

reproduction of mitochondria is unpredicable and there can be hundreds of them in a given cell (all with different mutations)

154

what gamete passes on the mitochondria?

ONLY the mitochondria of the OOCYTE are thought to be transferred to the next generation

155

what diseases have been confirmed to be mitochondrial in origin?

1) leber's Optic Neuropathy 2)kearns-sayre 3)Leighs syndrome 4) myoclonic epilepsy with ragged red fibers 5)NARP

156

what is Lebers hereditary optic neuropathy?

mitochondrial disorder characterized by mid-life onset of acute or subacute, painless, CENTRAL vision loss

157

what is Kearns-Sayre Syndrome?

Mitochondrial disorder characterized by opthalmoplegia, retinal pigment degeneration, and cardiomyopathy

158

what is leighs syndrome?

mitochondrial disorder, with early onset of neuropathy consisting of focal, bilateral lesions in one or more areas of the CNS

159

*myoclonic epilepsy with ragged red fibers?

*Mitochondrial disorder, with multisystem weakness, and myoclonus as first symptom, then epilepsy, then weakness and dementia

160

what is NARP?

Neurogenic weakness, Ataxia, and Retinitis Pigmentosa; mitochondrial disorder, with variable combination of developemental delay,

161

how did scientists trace back to a "kind of eve" or a mother to all living people?

with looking at mitochondrial DNA and how it mutates in a sort of molecular clock

162

is there diversity in the ability of a person to process or metabolize nutrients?

yes

163

is there evidence that nutrients can alter gene expression?

yes

164

can nutrients take away functions that genes would otherwise have to do?

yes nutrition can affect other metabolic pathways

165

do nutrients represent nature or nurture?

nurture

166

what is genetic counseling?

process by which patients at risk for a genetic disease are advised of the nature, risk and consquences of having or producing an affected child/relative

167

what does genetic counseling involve?

a collaborated effort b/t health professionals

168

how does almost all of the genetic counsiling start?

with a pedigree

169

what is duputytrens contracture?

a Fascia closure of the hand that is not always evident until mid-life.

170

how is deuputytrens contracture passed?

autosomal dominant

171

what is Cystic Fibrosis?

a metabolic failure of chloride ion transport across membranes

172

how is cystic fibrosis passed?

autsomal recessive

173

what is congenital dislocation of the hip syndrome?

relatively benign skeletal anomaly

174

hos is Congenital dislocation of the hip passed?

multifactorial

175

what is the most common quesiton in genetic counseling scenarios?

what is the chance that we might have another affected child? (recurrent risk)

176

what is the recurrent risk for an autosomal recessive disorder?

25.00%

177

what is the recurrent risk for an autosomal dominanit disorder?

50.00%

178

what is the recurrent risk for a rare, sex linked recessive?

25% overall (50% for male 0% female)

179

what is the recurrent risk for trisomies of autosomes?

slight increase over the normal population of the same age

180

what is the recurrent risk for a multifactorial inheritance?

usually less than 10% but often requires use of an empirical risk table

181

what are the two bolded questions that we need to know for genetic counseling for information?

1) what is the exact diagnosis 2) what aare the known facts and results of an examination of a family history

182

what is considered convential practice when it comes to genetic counseling?

refer

183

what are the red flags that should prompt a consideration of a genetic causality?

Family GENES

184

what does F GENES stand for?

Family history; Groups of congenital abnormalities; Extreme/ exceptional presentation, Neurodevelopemental delay, Extreme or exceptional pathology, Surprising lab values

185

what is the leading indication for prenatal diagnosis?

late maternal age

186

what are the other reasons for prenatal diagnosis and counseling?

1)prior child with it 2) prior history of miscarriage 3) known chromosomal defects in one of the parents 4) Family history 5)specific ethnic high-risk

187

what are some of the therapies that might be able to help get rid of many genetic dzs in the womb?

blocking or enhancing cellular function at transcription, translation or post-translation