Genetics 5

Question 1

examples of autosomal dominant disorders

Answer 1

• Marfan
• Huntington
• ocular disease

Question 2

examples of autosomal recessive disorders

Answer 2

• Tay-Sachs
• PKU
• ocular diseases

Question 3

examples of some X linked disorders

Answer 3

color deficiency, ocular albinism

Question 4

Marfan syndrome caused by

Answer 4

• mutation in structural proteins (defect in fibrillin genes)
• autosomal dominant
• clinical in skeleton, eyes, cardiovascular

Question 5

Ehlers-Danlos Syndrome

Answer 5

• mutation in structural proteins (defects in collagen synthesis or structure)
• single gene disorder
• 10 clinical and genetic variants
• hyperextensible skin

Question 6

familial hypercholesterolemia

Answer 6

-mutation in receptor proteins, most common mendelian disorder (autosomal dominant)

Question 7

where is the mutation for familial hypercholesterolemia

Answer 7

mutations in the LDL receptor gene

• loss of receptor synthesis
• impaired transport
• receptors that fail to bind LDL
• receptors that fail to internalize

Question 8

PKU- phenylketonuria

Answer 8

• mutations in enzyme proteins
• inborn error of metabolism
• autosomal recessive
• severe lack of phenylalanine hydroxylase

Question 9

tay-sachs disease

Answer 9

mutation in enzyme proetin- autosomal recessive

Question 10

what abnormality occurs in tay-sacks

Answer 10

HEXA gene on chromosome 15 deficient

-accumulation of gangliosidoses, brain principally affected

Question 11

neurofibromatosis type 1

Answer 11

• disfiguring clinical features

- neurofibromas on skin- nodules/tumors, cafe au lait spots, litchi nodules on iris

Question 12

types of neurofibromatosis

Answer 12

type 1- 90%, van Recklinghausen

type 2- 10% bilateral acoustic neurofibromatosis

Question 13

neurofibromatosis type 2

Answer 13

rare, mutant chromosome 22

-peripheral neurofibromas, cafe au last spots, bilateral acoustic neuromas

Question 14

what are some types of single gene disorders with atypical patterns of inheritance?

Answer 14

• diseases caused by triplet repeat mutations
• disease caused by mutations in mitochondrial genes
• diseases associated with genomic imprinting

Question 15

how are diseases caused by triplet repeat mutations

Answer 15

-amplification of specific sets of three nucleotides (CGG) within the gene disrupts the function

Question 16

fragile X syndrome

Answer 16

x-linked recessive, males affected only

FMR1 gene that maps to X

Question 17

inheritance for disease caused by mutations in mitochondrial genes

Answer 17

maternal- mitochondrial DNA derived entirely from ovum

Question 18

example of disease caused by mutations in mitochondrial genes

Answer 18

Leber’s hereditary optic neuropathy

progressive bilateral loss of central vision

Question 19

prader-willi

Answer 19

paternally derived on chromsome 15

Question 20

angelmans

Answer 20

materially derived chromosome 15