Pedigree Practice Examples

Question 1

Answer 1

X-linked Dominant

Question 2

Answer 2

X-linked with male lethality

Question 3

Answer 3

Mitochondrial Inheritance

Question 4

Answer 4

Autosomal Dominant with reduced penetrance

(low penetrance often complicates autosomal dominant inheritance)

Question 5

Answer 5

Autosomal Dominant

Question 6

Answer 6

Autosomal Dominant

Question 7

Answer 7

Autosomal Recessive

Question 8

Answer 8

Autosomal Dominant

Question 9

Most probable mode of inheritance?

Answer 9

Autosomal Recessive

(males and females equally affected, father-son transmission of affected recessive allele)

Question 10

Answer 10

Autosomal Dominant

Question 11

Answer 11

Autosomal Recessive

Question 12

Answer 12

Autosomal Dominant

Question 13

Which persons are carriers?

Which person introduced a second mutant allele into the family?

Is person 58 carrying the mutation?

Answer 13

Carriers: 1,4,15,17,19,20,23,30,40,44,51

Person introducing second mutant allele: 30 (tricky. 31 being an unaffected male means he cannot be a carrier)

Person 58: Probably not carrying (parent, 52, is not related to rest of family)

Question 14

Answer 14

X-linked Recessive

Question 15

Most probable mode of inheritance?

Answer 15

X-linked recessive

Question 16

Answer 16

X-linked Recessive