Flashcards in Enzyme Deficiencies Deck (71)
groups of inborn errors of metabolism
2. metabolic pathway
3. Function of enzyme
4. function of organelle
Most IEMs, genetics wise are ...
autosomal recessive or X linked recessive
IEMs of amino acid metabolism
branched chain aa metabolism - maple syrup urine disease
IEMs of Carbohydrate metabolism
monosaccharide metabolism - galactosemia, hereditary fructose intolerance
glycogen storage disorders - von gierke, cori, anderson, pompe, Mcardle syndromes; hepatic phosphorylase deficiency
IEMs of steroid metabolism
congenital adrenal hyperplasia
androgen insensitivity syndrome
IEM of Lipid metabolism
Lysosomal storage disorders
Lesch Nyhan syndrome
IEM of Porphyrin metabolism
Untreated PKU (phenylketonuria) leads to
severe intellectual impairments and development of seizures
Defects in branched chain AA metabolism leads to
Maple syrup urine disease
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
Branched chain AA?
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
What defect leads to Maple syrup disease?
branched chain ketoacid decarboxylase deficiency leads to Val, Leu and Ile
Single largest metabolic disorder?
Glucose 6 Phosphate dehydrogenase
G6PDD genetically is ....
X linked recessive
What is G6PD responsible for?
oxidative step of pentose phosphate pathway
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
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
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
Galactosemia pts are deficient in ...
galactose 1-phosphate uridyl transferase
Galactosemic newborn presents with
vomiting, lethargy, failure to thrive and jaundice within the second week of life
Untreated galactosemia leads to
Hereditary Fructose intolerance is caused by?
deficiency in fructose-1-phosphate aldolase (Aldolase B)
leads to build up of Fructose in liver
Glycogen stores are largest in
liver and muscles
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
Androgen insensitivity syndrome
Receptor defective leaving pt unresponsive to testosterone leading to external female characteristics
Autosomal dominant single gene disorder
High morbidity and mortality rates via premature coronary artery disease