Autosomal Recessive Disease

Question 1

What are the 4 features found in a pedigree for a autosomal recessive disease?

Answer 1

can’t follow the disease through the pedigree
see siblings affected - horizontal
equal incidence of males and females
may be evidence of consanguinity

Question 2

Name some autosomal recessive disorder

Answer 2

PKU
CF
congenital deafness
spinal muscular atrophy

Question 3

What is mucoviscidosis?

Answer 3

Cystic fibrosis

Question 4

What type of mutation causes CF?

Answer 4

deletion of CTT

Question 5

What is the aeitiology of spinal muscular atrophy?

Answer 5

wasting and weakness of proximal muscles

see degeneration of the cell bodies of motor neurones in the spinal cord

Question 6

What is genetic heterogeneity? What can it explain?

Answer 6

when defects in more than one gene account for a disorder

can explain that often normal hearing children born to deaf parents

Question 7

What is pseudodominance?

Answer 7

when an AR contain appears in subsequent generations

Question 8

What is heterozygous advantage?

Answer 8

e. g. sickle cell and malaria

e. g. cystic fibrosis and resistance to typhoid

Question 9

What is segregation analysis?

Answer 9

study of how a disorder is inherited in families to establish the mode of inheritance

Question 10

What are the 3 sources of fetal tissue used in prenatal diagnosis?

Answer 10

chorionic villus sampling
amniocentesis
?study fetal cells in maternal blood