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Flashcards in Enzyme Deficiencies Deck (71)
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groups of inborn errors of metabolism

1. metabolites
2. metabolic pathway
3. Function of enzyme
4. function of organelle

1

Most IEMs, genetics wise are ...

autosomal recessive or X linked recessive

2

IEMs of amino acid metabolism

PKU
Oculocutaneous albinism
branched chain aa metabolism - maple syrup urine disease

3

IEMs of Carbohydrate metabolism

G6PDD
monosaccharide metabolism - galactosemia, hereditary fructose intolerance
glycogen storage disorders - von gierke, cori, anderson, pompe, Mcardle syndromes; hepatic phosphorylase deficiency

4

IEMs of steroid metabolism

congenital adrenal hyperplasia
androgen insensitivity syndrome

5

IEM of Lipid metabolism

familial hypercholesterolemia

6

Lysosomal storage disorders

mucopolysaccharidoses
sphingolipidoses

7

Purine/pyrimidine metabolism

Lesch Nyhan syndrome
SCID

8

IEM of Porphyrin metabolism

Hepatic
Erythropoietic

10

Untreated PKU (phenylketonuria) leads to

severe intellectual impairments and development of seizures

10

Defects in branched chain AA metabolism leads to

Maple syrup urine disease

11

What deficiency causes PKU?

defect in the enzyme Phenylalanine hydroxylase (PAH) which converts Phenylalanine into Tyrosine, results in deficiency of Tyrosine which is required for melanin synthesis
this leads to buildup of phenylalanine which then converts to phenylpyruvic acid that is excreted through urine

12

Branched chain AA?

Valine
Leucine
Isoleucine

13

What is the prognosis for pts with Maple syrup disease?

tend to be susceptible to deterioration even with dietary restriction
tend to suffer recurrent illnesses from the catabolic protein breakdown

14

What defect leads to Maple syrup disease?

branched chain ketoacid decarboxylase deficiency leads to Val, Leu and Ile

15

Single largest metabolic disorder?

Glucose 6 Phosphate dehydrogenase

16

G6PDD genetically is ....

X linked recessive

17

What is G6PD responsible for?

oxidative step of pentose phosphate pathway

18

What type of cell in G6PDD pts is most affected?

Red blood cells because unlike other cells doesnt have other ways to handle oxidative stress

19

with G6PDD, there is a defect in ....

the ability to handle oxidative damage because there is reduced ability to produce NADPH, this is a potent reducer to protect against oxidative damage

20

G6PDD Pt suffers acute oxidative damage from exposure to moth balls, what could occur?

Hemolytic anemia - presents as jaundice (see in newborns with G6PDD), paleness, dark urine, fatigue, shortness of breath/rapid heart rate, splenomegaly

21

Galactosemia pts are deficient in ...

galactose 1-phosphate uridyl transferase

22

Galactosemic newborn presents with

vomiting, lethargy, failure to thrive and jaundice within the second week of life

23

Untreated galactosemia leads to

mental retardation
cataracts
liver cirrhosis

24

Hereditary Fructose intolerance is caused by?

deficiency in fructose-1-phosphate aldolase (Aldolase B)
leads to build up of Fructose in liver

25

Glycogen stores are largest in

liver and muscles

26

Congenital Adrenal Hyperplasia caused by

deficiency in 21-hydroxylase -90%
MCC of ambiguous genitalia in FEMALE newborns
salt losing form - presents 2-3 wks of life with circulatory collapse, hyponatremia, hyperkalemia

27

Androgen insensitivity syndrome

Receptor defective leaving pt unresponsive to testosterone leading to external female characteristics

28

Familial Hypercholesterolemia

Autosomal dominant single gene disorder
High morbidity and mortality rates via premature coronary artery disease

29

Familial Hypercholesterolemia is characterized by

problems with the LDL receptor which leads to increased endogenous synthesis of cholesterol