Bio 15 - Amino Acid Disorders Flashcards
What are the two ways to get PKU?
Deficiency in Phenylalanine hydroxylase. Be deficient in the cofactor tetrahydrobioptrin.
What are three phenylketones? In which disease do they build up?
Phenylacetate. Phenyllactate. Phenylpyruvate. They build up on patients who have PKU and eat phenylalanine. However, the neurotoxic effects are due to high levels of phenylalanine and NOT to phenylketones.
What are some symptoms of PKU?
Mental retardation. Growth retardation. Fair skin (phenylalanine is in the dopa to melanin pathway). Eczema. Musty body odor.
What is the treatment of PKU?
Avoid phenylalanine (aspartame, dairy products, meat, fish, chicken, eggs, beans, nuts). Add tyrosine into diet (now its essential). Might add tetrahydropbioptrin to diet.
What are the symptoms of the fetus of a mother with PKU?
Microcephaly. Intellectual disability. Growth retardation. Congenital heart defects.
What is the cause of alkaptonuria?
Defect in the enzyme Homogentisic acid oxidase (Homogentisate oxidase) which turns homogentisic acid to other by products that ends as Fumarate. It is a autosomal recessive disorder.
What are the two ways of having albanism?
Defect in the enzyme Tyrosinase or absence of melanocites (they come from neural crest cells).
What is the three main cause of Homocystinuria?
Defect of the enzyme cystathionine synthase. Decreased affinity of the cystathionine synthase for the pyridoxal phosphate. Deficiency of homocystine methyltrasnferase.
What are the symptoms of homocystinuria?
Mental retardation. Tall stature. Osteoporosis. Kyphosis. Atherosclerosis. Subluxation of the lens.
What are two genetic disorders that might cause subluxation of the lens?
Marfan syndrome (upward dislocation). Homocystinuria (donward dislocation).
What is the treatment for homocystinuria?
If cystathionine synthase problem: decrease methionine, increase cysteine, dietary B12, folate, B6.
What does S-adenosyl-methionine (SAM) do? What are the subunits required to make it?
Transfers methyl units in the body; very important in the conversion of norepinephrine to epinephrine. Also in the synthesis of phosphocreatine. Requires ATP and Methionine to make SAM.
What is the cause of Cystinuria?
Defect of the renal tubular AA transporter for [COLA] Cysteine, Ornithine, Lysine, Arginine. Normally found in the proximal convoluted tubule.
What does Cystinuria cause and what is the remedy?
Causes cysteine kidney stones. Prevention of stones achieved by acetazolamide.
What is the cause of maple syrup urine disease?
SMELLS like maple syrup, because it is filled with branched chain AAs [I LoVe maple syrup]: Isoleucine, Leucine, Valine. Caused by deficiency of branched chain alpha-ketoacid dehydrogenase complex, leading to alpha-ketoacids build up in the urine and blood.
