Browsing Pathways

Amifampridine, also known as Firdapse, is a presynaptic voltage-gated potassium channel blocker. This drug is used to treat Lambert-Eaton myasthenic syndrome. LEMS is an auto-immune disorder of the neuromuscular junction that is characterized by proximal muscle weakness, depressed tendon reflexes, and posttetanic potentiation in addition to autonomic dysfunction. This drug blocks presynaptic fast voltage-gated potassium channels, which prolongs the action potential and increases presynaptic calcium concentrations while increasing the acetylcholine concentrations at the neuromuscular junction. Increased intracellular calcium enhances the exocytosis of acetylcholine-containing vesicles and enhances impulse transmission at the synapses. It is administered as an oral tablet.

Aspartylglucosaminuria (AGU) is an inherited disease that is characterized by a decline in mental functioning, accompanied by an increase in skin, bone and joint issues. The disease is caused by a defect in an enzyme known as aspartylglucosaminidase (normally present in the liver and brain as well as other tissues). This enzyme plays a significant role in our bodies because it aids in breaking down certain sugars (for example, oligosaccharides) that are attached to specific proteins (for example, glycoproteins). Aspartylglucosaminuria itself is characterized as a lysosomal disease because it does deal with inadequate activity in an enzyme's function. Aspartylglucosaminidase functions to break down glycoproteins. These proteins are most abundant in the tissues of the body and in the surfaces of major organs, such as the liver, spleen, thyroid and nerves. When glycoproteins are not broken down, aspartylglucosaminidase backs up in the lysosomes along with other substances. This backup causes progressive damage to the tissues and organs. Aspartylglucosaminuria is a genetic condition that is inherited from both parents. The AGU patient is born with two copies of the mutated AGA gene. One copy comes from the mother’s egg and the other copy comes from the father’s sperm. In order to develop aspartylglucosaminuria, the individual must inherit changes in both of his AGU genes (autonomic recessive inheritance). When a person receives one changed form of the gene AGU from one of the parents, the individual is then classified as a carrier [Wikipedia].