Chap 7: Patterns of Single Gene Inheritance

Question 1

Genetic concerpts

Retinitis pigmentosa

X linked and autosomal forms

Answer 1

Locus heterogeneity

Question 2

Genetic concepts

2 parents with typical familial hypercholesterolemia

has a child with early develepment of symptoms and artherosclerosis

Answer 2

autosomal incompletely dominant

Question 3

Genetic Concepts

Couple in isolated community

has child with AR gyrate atrophy of retina

Child marries member of isolated community

has child with the same eye disorder

Answer 3

Imbreeding

Question 4

Genetic Concepts

Child wth severe NF1

Father appears phenotypically normal

Mother has few large cafe su lait spots, area of hypopigmentation and Lisch nodules (harmatomatous growths onthe iris)

Answer 4

Variable expressivity

Question 5

Genetic Concepts

Parents of normal stature has a child with achondroplasia

Answer 5

New Mutation

Question 6

Genetic Concepts

Adult male with myotonic dystrophy has cataracts, frontal balding and hypogonadism

Answer 6

Pleiotrophy

Question 7

Genetic Concepts

Man with Vitamin D rickets

Transfers condition to all of his daughters

None of his sons affected

Daughters have approx equally affected and unaffected sons and daughtes

Sons are more severly affected than the affected daughters

Answer 7

X-linked dominant inheritance

Question 8

Genetic Concepts

Boy with progressive muscular dystrophy

Onset in early childhood, wheelchair bound

Adult man also with progressive muscular dystrophy

still ambulant at the age of 30 years

Both have large deletions and dystrophin gene

Answer 8

Allelic heterogeniety

Question 9

Patient with recessive disorder

inherit both copies of one chromosome from same parent

no representation of that chromosome from the other parent

Answer 9

uniparental disomy

Question 10

child with MSUD born to parents

who are first cousins

Answer 10

Consanguinity

Question 11

set of alleles inherited together on a chromosome

Answer 11

Haplotype

Question 12

Trinucleotide repeats alleles

Not associated with disease phenotype

can expand during meiosis

Answer 12

permutations

Question 13

type of mitochondrial mutation

NOT passed from an affected mother to child

mother exhibits heteroplasmy for the mutation

Answer 13

Deletion

Question 14

Xeroderma Pigmentosum

Defect of _______ ______ repair

or

_________ repair

Answer 14

Nucleotide excision repair or postreplication

• Global genome repair subpathway

Question 15

two related disorders to Xeroderma Pigmentosum

also caused by defects of cellular mechanism for repair od UV induced DNA damage

Answer 15

• Cockayne syndrome
• Trichothiodystrophy
• They DO NOT show increase frequency for skin cancers

Question 16

measure of impact of condition on reproduction

Answer 16

Fitness

ratio

of offspring of individual affected with condition who survive to reproductive age / # off offspring of individuals who do not carry mutant allele

Question 17

Mode of inheritance for dyschondrosteosis

Answer 17

Psuedoautosomal inheritance

loci located in psuedoautosomal region on Xp and Yp

Mutation in SHOX gene

can demonstrate male to male transmission