Chronic Granulomatous Disease is the deficiency of NADPH oxidase. This is the enzyme responsible for the infection-armory of the cells called the Respiratory burst. The absence or the deficiency of this enzyme results in susceptibility to chronic pyogenic infections since there is no respiratory burst. People with CGD usually experience recurrent infections usually from Beta hemolytic Streptococcus bacteria.
Insulin deficiency results in Diabetes Mellitus that result in increased glucose level, glocusoria or presence of sugar in the urine and increase ketone levels. Galactosidase deficiency is a deficiency in the enzyme galactokinase. It is an autosomal recessive disease, resulting in increased galactose in the urine.
There are also diseases which are due to a disorder in the body amino acid components. These amino acids are the building blocks of protein in the body.
Homocystinuria is characterized by increased urine levels of homocystine. Maybe treated with dietary Vitamin B6 (pyridoxine) and cysteine. The disease is due to the inability of the body to methylate homocysteine into methionine. Homocysteine is oxidized into homocystine. Deficiency of cystathionine synthetase enzyme is the culprit for the disorder.
Phenylketonuria results from a deficiency of phenylalanine hydroxylase enzyme. The patient must eliminate phenylalanine from the diet. Tyrosine must be supplied in the diet since it cannot be made from phenylalanine. Neonatal screening test: Guthrie Test may show false negative if done at birth. Alkaptonuria is the deficiency of homogentisate oxidase enzyme which causes darkened urine when standing.
The body eliminates Urea to the urine through the Urea Cycle. In some cases, some of the enzymes involved in the cycle are deficient causing metabolic disorders.
Carbamoyl phosphate synthetase deficiency causes hyperammonemia. Omithine transcarbamoylase deficiency causes hyperammonemia, as well as orotic aciduria. Citrullinemia is a deficiency of argininosuccinate synthetase causes increased citrulline level. Argininemia deficiency of argininosuccinase causes argininosuccinate in the urine.
Another Biologic disorder is the Maple Syrup Urine Disease. This disease was named because of the "sweet urine." This disease is due to the deficiency of keto-acid (branched-chain) dehydrogenase.
There are also diseases which are due to the defect in the Glycogen storage. These are the following:
VON GIERKE'S (TYPE I GSD)
- Deficiency of glucose-6-phosphatase, Hepatomegaly is seen.
POMPE'S (TYPE II GSD)
- Deficiency of α-1.4-glucosidase and lysosomal acid maltase (a debranching enzyme),
- Cardiomegaly, restrictive cardiomyopathy, occurs as the heart stores glycogen
- Deficiency of the debranching enzyme, amylo-1.6-glucosidase,
- Effects limit dextrin conversion to glucose
MCARDLE'S (TYPE V GSD)
- Deficiency of muscle phosphorylase,
- Increased glycogen since can't breakdown glycogen to glucose
- There is weakness and cramps in the muscle
- Deficiency of liver phosphorylase
- Increased glycogen
PHOSPHORYLASE B KINASE DEFICIENCY
- Deficiency of liver phosphorylase b kinase
- Increased glycogen due to inability to activate to the Phosphorylase A
Lipid storage is also an important cycle in the body. Here are some Lipid Storage Diseases:
- Mutated LDL receptors that reduce binding of LDL
- Increased level of cholesterol
FAMILIAL LIPOPROTEIN LIPASE DEFICIENCY
- Deficiency of lipoprotein lipase
- Increased levels of chylomicron triglyceride
FAMILIAL LCAT DEFICIENCY
-Deficiency of lecithin: cholesterol acyltrasnferase
- Defective HDL synthesis
- Elevated cholesterol in tissue and decreased plasma HDL level
- Deficiency of Apo E3
- Defective synthesis of Apo B-lipid complex
Lysosomes have hydrolytic enzymes important in the body's metabolism. When these enzymes decrease, there is an accumulation of sphingolipids and sulfate which cause diseases. Here are some of those diseases:
- X-linked recessive deficiency of iduronosulfate sulfate
- This causes an increase of dermatan and heparan sulfate
- Causes mental and physical retardation
- Autosomal recessive deficiency of α-L-iduronidase
- Causes clouding of the cornea, joint degeneration, and heart disease
- Doest NOT cause retardation
- Deficiency of α-L-iduronidase
- Increased dermatan and heparan sulfate
- Causes clouding of the cornea, mental and physical retardation and early death
- This increases heparan sulfate
- Causes severe mental retardation
- Type III mucopolysaccharidosis
- Defective β- gangiliosidase A
Tay - Sachs disease
- Deficiency of hexosaminidase A
- Increased GM2-gangliosides
- This disease is associated with Ashkenazi (Eastern European)
- Jews and macular cherry-red spot
- Causes retardation and early death
- Deficiency of glucocerebrosidase
- Increased glucocerebrosides
- Deficiency of sphigomyelinase
- Increased sphingomycelin
- This associated with severe mental retardation and early death
- Deficiency of α-galactocerebrosidase A
- Increased ceramide trihexosides
- This is the only sex-linked recessive sulfatidosis
At present, scientists around the world are still doing research on finding cure for these disorders. However, detecting these disorders earlier can be done by performing the Newborn Screening 24-48 hours after birth.
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