MEDICAL NUTRITION PATHOLOGIES
Phenylketonuria
Phenylketonuria (PKU) is a rare inherited disorder caused by a defect in the enzyme Phenylalanine hydroxylase, responsible for breaking down phenylalanine into tyrosine. Without the necessary enzyme to process phenylalanine, there is an accumulation of this amino acid, leading to progressive damage to the central nervous system. With early and effective treatment, it is possible to prevent complications and achieve a good quality of life.
Maple Syrup Urine Disease
Maple syrup urine disease is a rare inherited disorder caused by a deficiency in the branched-chain ketoacid dehydrogenase enzyme complex. This results in a defect in the oxidative decarboxylation of the ketoacids of three branched-chain amino acids: leucine, isoleucine, and valine. With the enzyme failing, these acids accumulate, leading to toxicity and a distinctive odor resembling burnt sugar, hence the name of the disease.
Methylmalonic and Propionic Acidemias
Methylmalonic and propionic acidemias are a group of rare inherited disorders caused by defects in the catabolism of amino acids, primarily valine, isoleucine, threonine, and methionine. They are characterized by the abnormal accumulation of one or more organic acids in bodily fluids, leading to a series of metabolic disturbances.
Glutaric Acidemia Type 1
Glutaric Acidemia type 1 is a rare inherited disorder caused by a deficiency of the enzyme glutaryl CoA dehydrogenase in the catabolic pathway of lysine, hydroxylysine, and tryptophan. As a result of this enzymatic failure, there is an increase in glutaric acid and other metabolites, which are neurotoxic.
Homocystinuria
Classical homocystinuria is a rare inherited disorder characterized by a metabolic disorder of methionine metabolism, caused by a deficiency of the enzyme cystathionine beta-synthase. This enzymatic deficiency results in hypermethioninemia and accumulation of homocysteine, leading to vascular damage and thromboembolic complications.
Tyrosinemia
Tyrosinemia type 1 is a rare inherited disorder caused by a deficiency in the metabolic pathway of tyrosine, resulting from the failure of the enzyme fumarylacetoacetate hydrolase. This can lead to severe liver and kidney damage due to the accumulation of the toxic metabolites fumarylacetoacetate and its derivatives.
Urea Cycle Disorders
Disorders of the Urea Cycle result from inherited defects in one of the six enzymes involved in urea production. In these conditions, the production of ammonia is the main cause of pathogenicity. Additionally, a decrease in arginine is observed due to the enzymatic defect in one of these enzymes, making it an essential amino acid.
Hepatic Glycogen Storage Disease
These are disorders of glycogen metabolism in tissues due to enzymatic defects in the glycolytic or glycogenolytic pathway. They are classified based on the enzymatic deficiency and the affected tissue, either liver, muscle, or both. Hypoglycemia and hepatomegaly are the signs and symptoms present in all cases, but with a wide range of presentations.
Long-Chain Fatty Acid Oxidation Defects
The defects in long-chain fatty acid oxidation correspond to a group of rare inherited metabolic disorders that affect mitochondrial energy production from lipids. Among these disorders are:
The Ketogenic Diet (KD)
The Ketogenic Diet (KD) is a non-pharmacological and effective treatment used as an alternative method for managing refractory epilepsy since 1921. It consists of a diet high in fats, low in carbohydrates, and a protein intake recommended for the patient’s age. The goal of the KD is to mimic a fasting state without depriving the body of necessary calories, which promote growth and development in individuals.