EXAM 3 Medical Genetics

Question 1

X-linked recessive disorders

Answer 1

• duchess muscular dystrophy

- hemophilia A and B

Question 2

most common hemophilia

Answer 2

hemophilia A

90%

Question 3

what is hemophilia A associated with

Answer 3

factor VIII deficiency

Question 4

symptoms of hemophilia A

Answer 4

tendency toward easy bruising and massive hemorrhage after trauma

Question 5

Who does hemophilia A occur in

Answer 5

• males

- homozygous females

Question 6

is hemophilia A common or rare

Answer 6

rare - about 18,000 persons in US have hemophilia; about 400 new cases each year

Question 7

what kind of penetrance of hemophilia a

Answer 7

variable - variable effect of defective alleles

Question 8

severe disease of hemophilia a

Answer 8

Factor VIII levels of less than 1-2% normal

Question 9

what can someone experience with severe disease of hemophilia a

Answer 9

spontaneous bleeding into joints and muscles

Question 10

moderate disease of hemophilia a

Answer 10

factor VIII levels of 2-5% normal

Question 11

what can someone experience with moderate disease of hemophilia a

Answer 11

spontaneous bleeding

Question 12

mild disease of hemophilia a

Answer 12

factor VIII levels of 5-50% normal

Question 13

what does someone usually experience with mild disease of hemophilia a

Answer 13

bleeding following trauma or surgery

Question 14

X-linked dominant disorders

Answer 14

• X-linked hypophosphatemia
• focal dermal hypoplasia
• CHILD syndrome
• Rett syndrome
• Fragile X syndrome
• Incontinentia pigmenti
• Lujan–Fryns syndrome
• Orofaciodigital syndrome

Question 15

who is transmission of maternal inheritance

Answer 15

• affected women transmit to all offspring

- affected men do NOT transmit to offspring

Question 16

what results in in malfunctions of the respiratory chain for oxidative phosphorylation

Answer 16

mitochondrial inheritance

Question 17

what kind of inheritance is mitochondrial inheritance

Answer 17

maternal inheritance

Question 18

what reflects the extent of oxidative phosphorylation in the tissue

Answer 18

phenotypic effects

Question 19

what organs/systems are most affected by extent of oxidative phosphorylation

Answer 19

• CNS is most sensitive

- followed by skeletal muscle, heart muscle, kidney, liver

Question 20

mitochondrial inheritance diseases

Answer 20

• Leber’s hereditary optic neuropathy (LHON)
• Myocolonic epilepsy and ragged red fiber disease (MERRF)
• Kearns-Sayre syndrome

Question 21

loss of vision and cardiac dysrhythmia

Answer 21

Leber’s hereditary optic neuropathy (LHON)

Question 22

central nervous system abnormalities and deficiencies of skeletal and cardiac muscle function

Answer 22

Myoclonic epilepsy and ragged red fiber disease (MERRF)

Question 23

neuromuscular symptoms including paralysis of eye muscles, dementia, and seizures

Answer 23

Kearns-Sayre syndrome

Question 24

complex/multifactoral disorders

Answer 24

chronic diseases

Question 25

what 2 things are most chronic diseases affected by

Answer 25

both genetic and environmental factors

Question 26

examples of complex inherited disorders/chronic diseases

Answer 26

diabetes, CVD, asthma, cancer, dyslipidemia

Question 27

1. number of chromosomes in body | 2. number of pairs

Answer 27

46 | 23

Question 28

___ indicates only one set of chromosomes

Answer 28

haploid

Question 29

____ indicates two sets of chromosomes

Answer 29

diploid

Question 30

_____ refers to gain or loss of single chromosomes (ex, 45 or 47 chromosomes in somatic cells

Answer 30

aneuploidy

Question 31

alternate forms of a gene

Answer 31

allele

Question 32

where are alleles found?

Answer 32

on homologous chromosomes

Question 33

what are homologous chromosomes?

Answer 33

chromosomes that carry the same genes (ex 2 copies of chromosome 3)

Question 34

homologous chromosomes that differ

Answer 34

heterozygous

Question 35

homologous chromosomes that are the same

Answer 35

homozygous

Question 36

what is genotype?

Answer 36

the combination of alleles present?

Question 37

what is phenotype?

Answer 37

the expression pattern of a combined genotype

Question 38

what is phenotype dependent on?

Answer 38

genotype and environment

Question 39

sporadic mutations usually result in what type of disease?

Answer 39

autosomal dominant

Question 40

in autosomal dominant disorders, what percent of children will develop the condition

Answer 40

50%

Question 41

type of disorders that tend to affect structural proteins

Answer 41

autosomal dominant disorders

Question 42

how many defective alleles are needed to result in disease in autosomal dominant disorders?

Answer 42

Only one copy of a defective allele is needed

Question 43

autosomal dominant disorders- nervous system

Answer 43

huntington disease neurofibromatosis motonic dystrophy tubercous sclerosis

Question 44

autosomal dominant disorders- urinary

Answer 44

polycystic kidney disease

Question 45

autosomal dominant disorders- GI

Answer 45

familial polyposis coli

Question 46

autosomal dominant disorders- hematopoietic

Answer 46

hereditary spherocytosis | vin willebrand disease

Question 47

autosomal dominant disorders- skeletal

Answer 47

marfan syndrome Ehlers-danlos syndrome osteogenesis imperfecta achondroplasia

Question 48

autosomal dominant disorders- metabolic

Answer 48

familial hypercholesterolemia acute intermittent porphyria

Question 49

Marfan Syndrome % familial

Answer 49

70%-85% familial

Question 50

Marfan Syndrome % sporatic (new mutations)

Answer 50

15%-30% sporatic (new mutations)

Question 51

Marfan Syndrome occurs in how many people?

Answer 51

1:5000

Question 52

Marfan Syndrome has defect in what protein?

Answer 52

fibrillin-1

Question 53

Marfan Syndrome is Disorder in ________ tissues

Answer 53

connective tissues

Question 54

where is fibrillin-1 found in body?

Answer 54

Protein product is found in extracellular matrix proteins, especially in aorta, ligaments, ciliary zonules of the lens

Question 55

fibrillin-1 is Necessary for _____.

Answer 55

elasticity

Question 56

symptoms of Marfan syndrome

Answer 56

Lax joints, unusually tall, long extremities, including digits, spinal deformities (kyphosis, scoliosis), pectus excavatum, ectopia lentis, MVP, aortic valve incompetence, aorta weakening

Question 57

High risk of aortic dissection (especially thoracic) occurs in what autosomal dominant disease?

Answer 57

Marfan syndrome

Question 58

Autosomal Recessive Disorders occurs when (both or one) allele/s code for the disorder

Answer 58

both

Question 59

Autosomal Recessive Disorders Tend to result from failures in genes that code for _______.

Answer 59

enzymes, receptors, transporters

Question 60

in Autosomal Recessive Disorders, A person who has inherited the defective gene from only one parent often is _____.

Answer 60

disease-free