Biochem diseases flash Flashcards
Questions
Answer
Diabetes Type 1
beta-cells of pancreas no longer produce insulin, glucose has trouble entering cell. Body thinks starvation. Auto-immune. Juvenile onset
Diabetes Type 2
Tissue no longer responds well to insulin, insulin levels normal, but not normal response to it. Type A: Ab to insulin. Type B: Ab to insulin receptor. Takes years to develop. Some inherited forms.
Essential fructosuria
Defect in fructokinase. Fructose enters liver cell, but cannot be phosphorylated so it enters circulation. Elevated levels of fructose in urine. Positive result in reducing sugar test of urine. Control diet.
Hereditary Fructose intolerance
Defect in Aldolase B. F1P accumulates due to speed of fructokinase reaction. Hypoglycemia due to high F1P (glycogen degradation inhibited due to F1P inhibition of glyucogen phosphorylase [normal product is G1P]), gluconeogenesis impaired due to low aldolase. Lactic acidosis (inhibition of gluconeogenesis, lack of ATP, and uric acid blocking lactate release). Avoid fructose.
Galactosemia, classical
Defect in Gal-1P uridyl transferase. Elevated galactose in blood. Accumulation of gal-1P in nervous system leads to irreversible mental retardation. Accumulation of galactose and galactitol (alcohol) causes cataract formation. Gal-1P inhibits phosphoglucomutase and causes hypoglycemia. Remove lactose from diet.
Galactosemia, non-classical
Defect in galactokinase. Accumulation of galactose and galactitol causes cataract formation. Remove lactose from diet.
Lactose intolerance
Expression of lactase has decreased. Lactose is not absorbed into interestinal epithelial cells. Bacteria metabolize lactose and generate gas + acid
Cholera Toxin
Produced by bacteria. ADP ribosylate Gs to inhibit GTPase activity (always active)
Pertussis Toxin
Produced by bacteria. ADP ribosylate Gi to block GTP displacement (never activated)
Patau’s Syndrome
Trisomy 13. Sym: cleft lip, severe CNS anomaly, polydactyly
Edwards Syndrome
Trisomy 18. Sym: Low birth weight, CNS anomaly, heart defect
Down’s Syndrome
Trisomy 21. Sym: Hypotonia, characteristic features, developmental delay
Turner’s Syndrom
Monosomy X. Sym: short, amenorrhea, lack of secondary structural development
Klinefelter’s syndrome
XXY. Sym: Small testes, infertile, tall stature, learning problems
Triple-X
XXX. Sym: leaning disability, no physical abnormalities
XYY
Sym: learning and behavioral problems
Beriberi
Thiamine def. Alcohol blocks B1 uptake from gut. Heart has trouble getting energy (fluid retention, edema), CNS has trouble generating energy (confusion), nystagmus (uncontrolled eye movement)
Pyruvate DH complex def.
X-linked dominant (E1 defect). Lactic acidemia (pyruvate goes to lactate to continue glycolysis), brain problems (since it needs glucose)
G6PDH def.
Defect in G6P–> 6-Phosphogluconolactone +NADPH. RBC mainly affected since they have no mitochondria to generate NADPH. HMP shunt is needed for RBC to get NADPH and this is disrupted. RBC subject to oxidizing agents which can lead to premature lysis. X-linked recessive, noticed under conditions of oxidative stress, oxidizing drugs (Ex. anti-malarials, cause hemolytic anemia), or fava beans. Resistant to malaria.
von Gierke
Type 1 glycogen storage disease. Lack of G6 phosphatase (G6P–>glucose + P). Enlarged liver (hepatomegaly), severe fasting hypoglycemia. Increased glycogen in liver, no KB, lactic acidemia. Auto. R
Pompe disease
Type 2 glycogen storage disease. Lack of lysosomal alpha-glucosidase acdivity (glycogen–>glucose. Infantile form, death within 2 years. Cardiomegaly. Auto. R
Cori’s disease
Type 3 glycogen storage disease. Lack of debranching enzyme. Fasting hypoglycemia, hepatomegaly, glycogen with short outer chains. Normal blood lactate.
McArdle disease
Type 5 glycogen storage disease. Lack of muscle phosphorylase. Weakness and cramping after exercise. Inability to use muscle glycogen as energy source.
