Browsing Pathways

Triosephosphate isomerase deficiency is a genetic disorder caused by a mutation in the TPI1 gene. The mutation of this gene causes the production of enzymes that are unstable or enzymes that have reduced activity. This means that cells have reduced energy supplies as glycolysis is compromised. This disorder causes anemia, movement problems and muscle weakness. As a result of the lack of red blood cells to carry oxygen through the body, patients may experience fatigue and shortness of breath. Movement problems appear in early infancy, typically before the age of 2 in patients with this disorder. Treatment includes blood transfusions.

Corticosterone methyloxidase type I (CMO-I) deficiency, also known as 18-hydroxylase deficiency or aldosterone deficiency among other names, is a genetic disorder that is autosomally linked and caused by a defective CYP11B2 gene. This gene encodes the cytochrome P450 11B2 mitochondrial protein, also called aldosterone synthase, which is used to catalyze the conversion of 18-hydroxycorticosterone to aldosterone. This leads to a decrease in the amount of aldosterone present in the cells, which is responsible for an increased amount of salt excreted in the urine, known as salt wasting. In CMO-I deficiency, aldosterone levels are so low that they are undetectable in plasma.

Congenital Lipoid Adrenal Hyperplasia (CLA),also called steroid 20-22 desmolase deficiency and lipoid CAH, is an autosomal recessive disorder and caused by a defective cholesterol side-chain cleavage enzyme. Cholesterol side-chain cleavage enzyme catalyzes the conversion of cholesterol into 20α-Hydroxycholesterol which is also a substrate of cholesterol side-chain cleavage enzyme. This disorder is characterized by a large accumulation of cholesterol in the mitochondrial. Symptoms of the disorder is not clear. Extra glucocorticoid and mineral replacement could be the potential treatments.

Hydroflumethiazide (also known as Esidrix or Oretic) is an organic compound that used for diuretic. It can inhibit the solute carrier family 12 member 3 (also known as sodium-chloride symporter) in the nephron to prevent water reabsorption. Solute carrier family 12 member 3 is also used for sodium reabsorption that count for 5% of total amount. Solute carrier family 12 member 3 transports chloride and sodium from lumen to epithelial cell, and sodium/potassium ATPases facilitate the export of sodium to basolateral interstitium to provide sodium gradient that will increase the osmolarity in interstitium, which lead to establishment of osmotic gradient for water reabsorption.

Cystinuria is a genetic condition caused by mutations in the SLC7A9 or SLC3A1 gene. These two genes are responsible for creating subunits of a protein that reabsorbs cystine into the blood, located in the kidneys. The mutations cause this process to be compromised and allows the amino acids to build up and have a high concentration in urine. This causes crystals to form and become stones as they grow larger. These stones can become lodged in the bladder or in the kidneys which can cause pain, develop infection and disrupt the passing of urine through the urinary tract if the stones create a blockage there.

Furosemide (also named Lasix) is a medication that can be used for high blood pressure and fluid build-up which caused by heart failure, liver scarring, or kidney disease. Furosemide can bind and inhibit sodium-potassium-chloride cotransporter (NKCC2/SLC22A1) to prevent the water reabsorption in nephron. Inhibition of sodium-potassium-chloride cotransporter can prevent transportation of sodium from lumen to basolateral interstitium, which lead to more hypertonic in lumen and less hypertonic in basolateral interstitium that will allow water reabsorption through nephron.

Chlorothiazide (also known as Diuril) is an organic compound that used for diuretic. It can inhibit the solute carrier family 12 member 3 (also known as sodium-chloride symporter) in the nephron to prevent water reabsorption. Solute carrier family 12 member 3 is also used for sodium reabsorption that count for 5% of total amount. Solute carrier family 12 member 3 transports chloride and sodium from lumen to epithelial cell, and sodium/potassium ATPases facilitate the export of sodium to basolateral interstitium to provide sodium gradient that will increase the osmolarity in interstitium, which lead to establishment of osmotic gradient for water reabsorption.

GABA-transaminase deficiency, also known as gamma-amino butyric acid transaminase (GABA-T) deficiency, is an extremely rare autosomal recessive inborn error of metabolism (IEM) that is caused by a defect in the ABAT gene, which codes for 4-aminobutyrate (GABA) aminotransferase. This enzyme is present in several tissues in addition to brain and is most active in liver, and it catalyzes the conversion of GABA and 2-oxoglutarate into succinic semialdehyde and L-glutamate, and when it is deficient, GABA levels in the body, specifically the cerebrospinal fluid, are elevated. GABA is a neurotransmitter found in the nervous system that inhibits neurons from firing, and also affects the development of the brain, as well as regulating muscle tone. GABA-T can also convert beta-alanine and oxoglutaric acid to L-glutamic acid and malonic semialdehyde as part of the beta-alanine metabolism pathway, and when it is mutated, leads to an accumulation of beta-alanine within the cell. GABA-T deficiency is characterized by an increase of GABA levels in the cerebrospinal fluid. Symptoms of this disorder include low muscle tone and psychomotor retardation, as well as potential epilepsy and excessive sleeping. Treatment with Flumanezil, sold as Anexate, Lanexat, Mazicon or Romazicon, a GABA-A antagonist, has been tested and may be beneficial in some cases, and potentially more effective if started at a young age. It is estimated that GABA-T deficiency affects less than 1 in 1,000,000 individuals, as only five cases have been reported in literature as of 2017.

Carnosinemia, also known as carnosinemia, is a rare inborn error of metabolism (IEM) and recessive autosomal disorder caused by a defective CNDP1 gene which encodes for carnosinase. Carnosinase is a dipeptidase enzyme that catalyzes the breakdown of Carnosine into alanine and histidine. This disorder is characterized by secretion of large amounts of carnosine and anserine in the urine but low levels of methylhistidine. Patients also have unusually high concentrations of homocarnosine in the cerebrospinal fluid. Other symptoms include progressive neurologic disorders characterized by severe mental defect and myoclonic seizures. There is no known cure for Carnosinemia therefore treatment involves management of symptoms. There have been about 30 cases of Carnosinemia reported worldwide.

Azatadine is a first-generation piperidine H1-antihistamine. H1-antihistamines interfere with the agonist action of histamine at the H1 receptor and are administered to attenuate inflammatory process in order to treat conditions such as allergic rhinitis, allergic conjunctivitis, and urticaria. Reducing the activity of the NF-κB immune response transcription factor through the phospholipase C and the phosphatidylinositol (PIP2) signalling pathways also decreases antigen presentation and the expression of pro-inflammatory cytokines, cell adhesion molecules, and chemotactic factors. Furthermore, lowering calcium ion concentration leads to increased mast cell stability which reduces further histamine release. First-generation antihistamines readily cross the blood-brain barrier and cause sedation and other adverse central nervous system (CNS) effects (e.g. nervousness and insomnia). Second-generation antihistamines are more selective for H1-receptors of the peripheral nervous system (PNS) and do not cross the blood-brain barrier. Consequently, these newer drugs elicit fewer adverse drug reactions.