Table of Contents
- 1 Why does phenylalanine cause mental retardation?
- 2 What is the most common amino acid disorder?
- 3 Why does high phenylalanine cause brain damage?
- 4 Can aspartame cause mental retardation?
- 5 What is the cause of phenylketonuria?
- 6 Does PKU lead to mental retardation?
- 7 How is mental retardation prevented in phenylketonuria?
- 8 Which is an example of an amino acid metabolic disorder?
- 9 How does phenylalanine affect the brain and nervous system?
Why does phenylalanine cause mental retardation?
Mutations in the PAH gene can cause phenylketonuria (PKU), a disorder that can change cells in the brain. The faulty protein allows dangerously high levels of phenylalanine to accumulate in the brain, poisoning the cells. If a person with PKU consumes too much phenylalanine, the build-up can cause mental retardation.
What is the most common amino acid disorder?
Organic acidemias are conditions characterized by the accumulation of organic acids in body tissues and fluids, especially urine. The most common of these disorders are autosomal recessive conditions that involve the metabolism of the branched-chain amino acids leucine, isoleucine, and valine.
Why does high phenylalanine cause brain damage?
Because nerve cells in the brain are particularly sensitive to phenylalanine levels, excessive amounts of this substance can cause brain damage. Classic PKU, the most severe form of the disorder, occurs when phenylalanine hydroxylase activity is severely reduced or absent.
Why there is mental retardation in phenylketonuria?
1) deficiency. PAH is a liver-specific enzyme that catalyses the hydroxylation of l-phenylalanine (Phe) to l-tyrosine in the presence of the cofactor, tetrahydrobiopterin. Accumulation of phenylalanine generates a brain damage and consequently irreversible mental retardation.
Is phenylalanine a neurotoxic?
Since phenylalanine can be neurotoxic and can affect the synthesis of inhibitory monoamine neurotransmitters, the phenylalanine in aspartame could conceiveably mediate neurologic effects.
Can aspartame cause mental retardation?
In addition, prenatal consumption of aspartame might result in mental retardation, impaired vision, birth defects and is thought to play a role in the pathogenesis of Alzheimer’s disease; furthermore, it is implicated in disruption of learning and emotional functioning due to its involvement in alteration of certain …
What is the cause of phenylketonuria?
PKU is caused by a defect in the gene that helps create the enzyme needed to break down phenylalanine. Without the enzyme necessary to process phenylalanine, a dangerous buildup can develop when a person with PKU eats foods that contain protein or eats aspartame, an artificial sweetener.
Does PKU lead to mental retardation?
After all, PKU is a rare, genetic disorder of amino acid metabolism identified at birth by pediatricians and treated by geneticists. But, PKU is also a disorder that, if left untreated, leads to severe behavioral difficulties and ultimately mental retardation.
Is NutraSweet a neurotoxin?
Neurotoxin #1: Aspartame. Aspartame is a popular artificial sweetener found in diet sodas, processed foods labeled “sugar-free,” and those little blue packages that go by the brand names Equal or NutraSweet.
Which is the most common cause of mental retardation?
Sometimes mental retardation is caused by an abnormality in the chromosomes rather than the individual genes. Down syndrome, one of the most common causes of mental retardation, is caused by an extra chromosome in the cells. Another fairly common chromosomal defect is fragile X also termed Martin-Bell syndrome or marker X syndrome.
How is mental retardation prevented in phenylketonuria?
In phenylketonuria, mental retardation is prevented by a diet that severely restricts natural protein and is supplemented with a phenylalanine-free amino acid mixture. The result is an almost normal outcome, although some neuropsychological disturbances remain.
Which is an example of an amino acid metabolic disorder?
Cystinosis is a metabolic disease characterized by an abnormal accumulation of the amino acid cystine in various organs of the body such as the kidney, eye, muscle, pancreas, and brain. Different organs are affected at different ages.
How does phenylalanine affect the brain and nervous system?
The high plasma phenylalanine concentrations increase phenylalanine entry into brain and restrict the entry of other large neutral amino acids. In the literature, emphasis has been on high brain phenylalanine as the pathological substrate that causes mental retardation.