Genetic Disorders Flashcards
What enzyme is defective in albinism
Tyrosinase
What is function of Tyrosinase
Convert DOPA to melanin
What is the difference between between vitiligo and albinism?
Albinism the number of melanocytes is not affected. In vitiligo it is
Diagnosis?
- light skin/ hair
- ocular defects:
- strabismus and nystagmus
Albinism
Inheritance pattern of pyruvate dehydrogenase deficiency ?
X linked recessive
What is the function of pyruvate dehydrogenase
Convert pyruvate into acetyl-CoA to participate in TCA cycle
Diagnosis?
- neurological defects
- elevation of lactate and alanine
- lactic acidosis!
Pyruvate dehydrogenase deficiency
Treatment of pyruvate dehydrogenase deficiency?
Consume high fat diet, ketogenic focusing on consuming a lot of lysine and leucine (ketogenic a.a)
What is the function of pyruvate kinase?
ATP depletion especially in RBCs because they have no mitochondria (exclusively rely on glycolysis)
Diagnosis?
Newborn w/
- extravascular hemolysis (only in spleen)
- increased indirect bilirubin (jaundice, itchy skin)
- increased 2,3 BPG —> right shift
- Presence of burr cells
-negative osmotic fragility test
Pyruvate kinase deficiency
What is the function of G6PD?
- crucial role in pentode phosphate pathway
- generates NADPH
Who is G6PD deficiency prevalent in ?
- African Americans
Inheritance pattern of G6PD deficiency?
X linked recessive
What enzyme deficiency decreases GSH?
Pyruvate kinase. GSH is an antioxidant.
Blood smear presents
- Heinz bodies
- bite cells
After patient takes anti microbial drug
G6PD deficiency
What is the enzyme that is defective in essential fructosuria?
Frucktokinase
Which condition is benign?
Essential fructosuria
Hereditary fructose intolerance
Essential fructosuria because fructose is not trapped and can exit cells freely in urine
What enzyme is defective in hereditary fructose intolerance?
Aldolase B —> ACCUMULATION of fructose -1-phosphate
Diagnosis? - hypoglycemia Baby after breastfeeding - vomiting - tremors, seizures, lethargy
Hereditary fructose intolerance
What organ does hereditary fructose intolerance damage?
Liver
What accumulates in galactosemia?
Galactose and galactose-1-phosphate
What enzyme is defective?
UDP Transferase
What is produced during classic galactosemia that is not physiologically normal?
Galactiol alcohol
Diagnosis?
Infant while breastfeeding
Presents w/ hepatomegaly, jaundice, failure to thrive, infantile cataracts (can’t visually track objects/ develop social smile), intellectual disability
Classic galactosemia
What is a rare complication of galactosemia in neonates?
E. Coli sepsis
What enzyme is deficient in galactokinase deficiency? And what accumulates?
Galactokinase
Galactose and galactitol
What is more benign classic galactosemia or galactokinase deficiency?
Galactokinase deficiency
Diagnosis?
Infant with cataracts
What is the inheritance pattern of ornithine transcarbamylase deficiency?
X linked recessive
What is elevated in ornithine transcarbamylase deficiency? And what is defective?
Ammonia
urea cycle
Diagnosis?
-hyper-ammonia symptoms ( lethargy, asterisks)
- LOW BUN,
elevated carbamoyl phosphate and orotic acid
What is the defect in phenylketonuria? What accumulates
Metabolizing phenalyanine to tyrosine
Phenylketones in urine
Tyrosine is decreased
What enzyme is defective in PKU?
Phenanylaine hydroxylase or it’s cofactor BH4
What is the treatment?
Tyrosine becomes ESSENTIAL in diet
Diagnosis?
Infant 2-3 days after birth
- seizures, cognitive delays, failure to thrive,
- light complexion
- eczema,
- musty body order
PKU
