Enzyme Deficiency Disorders (Baker) Flashcards
What are the amino acid metabolism disorders?
Phenylketonuria (PKU), Oculocutaneous Albinism (OCA), Maple Syrup Urine Disease
What are the carbohydrate metabolism disorders?
G6PDD, Galactosemia, Hereditary Fructose Intolerance
Glycogen storage diseases affect what parts of the body?
Liver & muscles
What are the glycogen storage disorders that affect the liver?
Von Gierke Disease, Cori Disease, Anderson Disease, Hepatic Phosphorylase Deficiency
What are the glycogen storage diseases that affect muscle?
Pompe Disease & McArdle Disease
What are the steroid metabolism disorders?
Congental Adrenal Hyperplasia (CAH) & Androgen Insensitivity Syndrome
What is the lipid metabolism disorder?
Familial hypercholersterolemia
What are the lysosomal storage disorders?
Mucopolysacchridoses, Sanfilipo Syndrome, Sphingolipodoses
What are the nucleic acid metabolism disorders?
Adensosine Deaminase Deficiency & Lesche Nyhan Syndrome
What are the porphyrin metabolism disorders?
Acute Intermittent Porphyria & Congenital Erythropoietic Porphyria
Explain PKU.
Phenylalanine hydroxylase defienciency; can’t make tyrosine from phenylalanine. Seizures, intellectual impairments. Tx - dietary restrictions.
Explain OCA.
Tyrosinase deficiency; can’t make melanin from tyrosine. No pigment in hair, eyes, skin, nystagmus.
What are the 2 types of OCA?
Type 1: classical, chormosome 11q. Type 2: mutation on P gene of chromosome 15q.
Explain Maple Syrup Urine Disease.
Branched-chain ketoacid-decarboxylase deficiency; can’t break down Val, Leu, or Ile - get build-up of amino acids. Urine smells like maple syrup, vomiting, death. Tx - dietary restrictions.
Explain G6PDD.
G6P dehydrogenase deficiency - enzyme between 1st step (oxidative) of PPP pathway, which is particularly critical for RBCs. Low production of NADPH (reducer). Triggered by oxidative assault.
Explain Galactosemia.
Galactose-1P uridyl transferase deficiency - enzyme that converts galactose-1P to G1P. Can’t break down dietary sugar. Vomiting, lethargy, failure to thrive, jaundice, mental retardation, cataracts, cirrhosis. Tx - dietary restrictions.
Explain Hereditary Fructose Intolerance.
Fructose-1P aldolase deficiency - enzyme that converts fructose-1P to G3P. Can’t break down dietary fructose. Failure to thrive, vomiting, jaundice, seizures. Tx - dietary restrictions.
Explain Von Gierke Disease.
Glucose 6-phosphotase deficiency - enzyme that converts G6P to glucose. No glycogen breakdown.
Explain Cori Disease.
Amylo-1,6-glucosidase deficiency - enzyme that debranches glycogen to make G1P. No glycogen breakdown.
Explain Anderson Disease.
Glycogen Brancher enzyme deficiency - enzyme that convertes UDP-G to glycogen. No glycogen synthesis.
Explain Hepatic Phosphorylase Deficiency.
Glycogen phosphorylase deficiency - enzyme that converts glycogen to G1P. No glycogen breakdown.
Which glycogen storage diseases result in no glycogen breakdown?
Von Gierke Disease, Cori Disease, Hepatic Phosphorylase Deficiency Syndrome, Pompe Disease, McArdle Disease
Which glycogen storage disease results in no glycogen synthesis?
Anderson Disease
Explain Pompe Disease.
Alpha-1,4-glucosidase lysosomal enzyme deficiency. No glycogen breakdown. Presents in infancy with hypotonia, enlarged heart, cardiac failure.
Explain McArdle Disease
Muscle phosphorylase deficiency. No breakdown of glycogen during exercise. Presents in adolescence with muscle cramping during exercise.
Explain CAH.
21-hydroxylase deficiency - enzyme that converts cholesterol to aldosterone/cortisol. Accumulation of adrenocorticosteroids leads to virilized female body. Tx - cortisol supplementation.
Explain Adrogen Insensitivity Syndrome.
Defective testosterone receptors. 46 X,Y - externally female, internally male.
Explain Familial Hypercholsterolemia
Problem with LDL receptor that leads to reduced/defective biosynthesis/transport and abnormal binding by/internalization of receptor. Increased endogenous synthesis of cholesterol. Very high cholesterol levels, xanthomata, early coronary events. Tx - dietary restrictions, statins.
Explain Mucopolysaccharidoses. What syndrome is associated with this?
Can’t break down complex macromolecules - accumulation of sulfated polysacchrides (Hunter Syndrome). Skeletal, vascular, or CNS findings, coarsening of features.
Explain Sanfilipo Syndrome.
Can’t break down complex macromolecules - accumulation of heparin sulfate. Skeletal, vascular, or CNS findings, coarsening of features.
Explain Sphinogolipodoses. What syndromes are associated with this?
Can’t break down complex macromolecules - accumulation of lipids, glycolipids in brain, liver, spleen (Tay Sachs & Gaucher). CNS involvement, progressive mental deterioration, seizures.
What is Tay Sachs?
Sphingolipodoses syndrome in which decrease in beta-hexoaminidase leads to increase in GM2 ganglioside. Poor feeding, lethargy, developmental delays, cherry red spot on fundus.
What happens in Gaucher Types 1, 2, & 3?
Sphingolipodoses syndrome in which there is a decrease in glucosylceramide beta-glucosidase. Type 1 - pain in limbs, tendency to bone fracture, hepatomegaly, no CNS involvement. Type 2 - heavy CNS involvement, no treatment. Can treat types 1 &3 with analgesics or splenectomy.
Explain Adenosine Deaminase Deficiency.
Adenosine deaminase deficiency - enzyme that converts adenosine/AMP to inosine/IMP. Immunodeficiency (“Bubble Boy”), problem with T/B cell signaling.
Explain Lesche Nyhan Syndrome.
HGPRT deficiency - enzyme that converts hypoxanthine/guanine to IMP/GMP. Accumulation of purines leads to uric acid in blood. Uncontrolled movements, spasicity, mental retardation, compulsive self mutilation.
Explain Acute Intermittent Porphyria.
Uroporphyrogin-I synthase deficiency - enzyme that converts porphobilinogen to hydroxymethyl-bilane. Increased secretion of poprphbilinogen and delta aminolevulinic acid in urine. Leads to vomiting, mental/emotional disturbance, coma.
Explain Congenital Erythropoietic Porphyria.
Uroporphyrogen-3-cosynthase deficiency - enzyme that converts hydroxymethyl bilane to uroporphyrogen 3. Extreme photosensitivity, hemolytic anemia. Most require multiple transfusions and splenectomy.
