Autosomal Recessive disorder explanation and PKU

Question 1

What can increase the chance of passing on an autosomal recessive disorder

Answer 1

incest (consanguineous mating)

Question 2

What are the occurance risk percentages of autosomal recessive disorders

Answer 2

1/4 for affected child
two in four for a carrier child
one in four for a normal (noncarrier, unaffected)

Question 3

Is onset of ARD’s early or late

Answer 3

early

Question 4

What are ARD’s characterized by

Answer 4

loss of function mutations

Question 5

In most cases of hyperphenylalaninemia what is deffiecient

Answer 5

phenylalanine hydroxylase (PAH)

Question 6

What is PKU?

Answer 6

Elevated levels of Phenylalanine that is too toxic to brain

Question 7

What percentage in the white and Asian population is affected by PKU?

Answer 7

1 per 10,000

Question 8

What percentage of phenylalanine is consumed in a child’s diet?

Answer 8

less than 50% is used for protein synthesis

Question 9

What are symptoms of PKU

Answer 9

S   Seizures
M  Microcephaly
E   Eczema
L   Light colored hair and skin
S   Smelly odor from metabolites

Question 10

What is the treatment for PKU?

Answer 10

Phenylalanine free diet

Question 11

Why is PAH important

Answer 11

it converts phenylalanine into tyrosine

Question 12

What is done to check for PKU early

Answer 12

routine screening of phenylalanine levels

Question 13

Is a high phenylalanine diet a risk factor for a pregnant womans child

Answer 13

yes

Question 14

How many genes are affected in an autosomal recessive disorder?

Answer 14

Both gene pairs