Exam 2 BCM DEFECIENCIES Flashcards
Lactose Intolerance
Lactose Intolerance happens when you have a deficiency in the enzyme lactase in your gut, where it can’t break down lactose into galactose and glucose. So, lactose sits there, water comes into your gut via osmosis, AND bacteria then create methane and H2 gas (makes you bloaty and gasy). Pt’s that have this can fix it by taking a pill that contains the enzyme lactase
Phenylketonuria
A defect in enzyme phenylalanine hydroxylase that prevents the conversion of Phe –> Tyr, resulting in excess phenylketones in the urine. Incidence is around 1/10,000 but it varies from country to country. Screened for at birth because untreated phenylketonuria results in neuro symptoms and low IQ. Treatment is a special diet, avoiding phenylalanine and aspartame (nutrasweet)
Fumarase Deficiency
Tay Sachs
A defect in hexosaminidase A (an enzyme in lysosomes that breaks down ganglioside lipids by removing the sugar heards) causing an accumulation of lipids in the lysosomes of brain cells. Causes progressive retardation, paralysis, blindness, and death by age 3
Antitrypsin Defeciency
A defect in the inhibitor of certain proteases, including trypsin and elastase. Too much elastase activity breaks down the structural proteins in the lungs, increasing the risk of emphysema (this condition is exascerbated by smoking)
What is the enzyme that viagra inhibits?
Phosphodiesterase
Explain the common mutation in asians that results in not being able to drink alcohol
(note inhibiting the enzyme aldehyde dehydrogenase is a common way to treat alcoholics, creating bad side effects when you drink alcohol)
Explain why alcoholics can’t take tylenol/acetaminophen
What happens when you have a deficiency in Vitamins B1, B2, B3, and B5?
Deficiencies in vitamins B1 (thiamine), B2 (riboflavin), B3 (niacin) and B5 (pantotheate) cause LESS ACTIVE PDH COMPLEX
Explain Lactate Dehydrogenase A Deficiency (LDHA)
What lactate dehydrogenase does, is it catalyzes a redox reaction where pyruvate is reduced to lactate and NADH is oxidized to NAD+
Pt’s who have this deficiency cannot maintain moderate levels of exercise due to an inability to utilize glycolysis to make ATP needed for muscle contraction in anaerobic conditions.
When lactate dehydrogenase levels are insufficient, the level of NAD+ becomes limiting during exercise and flux through the glyceraldehyde 3-P dehydrogenase reaction is inhibited.
Explain Galactosemia
Galactosemia is a genetic disorder caused by a deficiency either in galactokinase, or in galactose-6-P uridyl transferase (“classic” more severe kind).
In first case: causes elevated galactitol levels, causing cataracts
In second, more severe case: elecated galactitol levels AND elecated galactose-6-P (causes cataracts, hepatic dysfunction, brain retardation)
Treatment: remove galactose from diet (avoid lactose products, aka dairy)
Explain Aldolase B Deficiency/ “Hereditary Fructose Intolerance”
Defective Aldolase B can’t cleave fructose-6-P
This causes an increase of fructose 6-P inside of the cells (“intracellular fructose trapping”)
This then causes a depletion in Pi and ATP levels
Symptoms: hypoglycemia, vomiting, jaundice, liver failure
Treatment: removal of dietary sucrose (table sugar and desserts) and fructose (honey, fruit)
Genetic deficiency of glycogen degradation and Glucose-6P ase enzymes lead to ______
Genetic defeciency of glycogen degradation and G-6-Pase enzymes lead to INCREASE in KETONE BODIES
Explain Pyruvate Carboxylase Genetic Deficiency
Pyruvate Decarboxylase Deficiency:
Increased blood Alanine, Pyruvate, and Lactate levels
Causes recurrent seizures, developmental delays,
metabolic acidosis
Explain PDH Genetic Deficiency
Explain how aresenic poisoning relates to PDH defeciency
PDH Genetic Deficiency:
Increases Circulatory pyruvate and lactate
Symptoms: microcephaly, poor muscle coordination, mental retardation
Arsenic poisoning limits the shuttling of lipoic acid between the reduced and oxidized forms (this mimics PDH defeciency, and creates increase pyruvate and lactate in the blood)
