Cholesterol Acyltransferase: The gene for this enzyme is on chromosome 1. It is an enzyme located in the membrane of the endoplasmic reticulum (ER) and acts to join cholesterol molecules to long chain fatty acids for storage purposes.
This is a lysosomal enzyme that breaks down a substance called Sphingomyelin. This enzyme is defective to a greater or lesser extent in NPA/B disease.
This is a particular form of gene that occur in pairs; one on each chromosome inherited from each parent.
These are organic molecules that link together in order to form proteins.
This refers to the failure of muscular coordination, which can lead to irregular muscle action.
Refers to chromosomes 1 to 22; i.e. any chromosome other than the sex chromosomes.
In the context of this site, and in scientific discourse at large – the term ‘bases’ is used to describe a number of chemicals that are used as introduction code by DNA and RNA. These are abbreviated as; A, T, C, and G in DNA, and as A, U, C, G in RNA.
This term refers to a highly selective barrier formed by blood vessels and a type of brain cell (called astrocytes) that allow only appropriate molecules to cross from blood to brain; e.g. oxygen and sucrose. The blood brain barrier aims to keep potentially harmful molecules out of the brain.
The ‘stalk’ of brain tissue which connects the spinal cord, cerebellum, and cerebral hemispheres. Breathing, heart-rate, blood pressure, control of eye movements, and nerves of the head/neck reside in the brainstem. As a result ‘brain death’ is defined by irreversible loss of the brainstem function.
An essential element of all animals and plants – as it is vital in all cells.
A substance that accelerates a chemical reaction without being changed itself. An example of a catalyst can be found with enzymes.
This refers to the sudden loss of muscle tone, usually brought on by a strong stimulus such as laughter or anger. Cataplexy is believed to represent a fragment of rapid eye movement (REM) sleep that intrudes into the otherwise normal consciousness. Cataplexy correlates with the dysfunction of the upper brainstem.
The basic unit for life! Cells are bound by a protective membrane and contain all the information; lysosome, mitochondria, nucleus, DNA, production mechanisms and material, which allows for communication links with other cells…which consequently allows for other cells to replicate and grow into a living creature, whose cells can replicate and in turn, function.
This is the part of the brain located behind the brain stem under the main mass of the brain. It is known to be responsible for the coordination of movement and contains Purkinje cells (which are badly affected by NP-C).
A fatty substance known as sterol that is a major component of cell membranes; especially the main (plasma) membrane. It is also required for digestive bile acids and sterol hormones. Some cholesterol is taken in from certain foods but most is produced by the cells of the body, notably the liver. A constant supply of cholesterol is needed for cell growth and maintenance and is distributed in the blood stream by LDL.
A lysosomal enzyme that cuts (hydrolyses) LDL cholesterol molecules free from their fatty acid tails. Wolman’s disease results from defects within this enzyme.
Located in the nucleus of the cell, these are very long super-coiled DNA molecules that carry the information template which enable the replication of cells in the associated living creature.
Proteins that coat vesicles, and direct their movement in cells.
A mutation in a gene that occurs in a high percentage of patients affected by a specific disease: e.g. I1061T in Niemann-Pick Type C.
The outer layer of any organ; e.g. cerebral cortex, or cerebellar cortex. In the brain the cortex consists of grey matter (also referred to as neurons).
The internal liquid/gel content of a cell that surrounds the sub-cellular organelles and contains many of the simple and complex molecules required for the cell to function. The cytosol is not uniform but varies throughout its extent, and is organised by the internal skeleton of the cell.
These are cells containing two sets of chromosomes, and as a result: two copies of genes. Most cells of an organism (except sex cells and red blood cells) are diploid.
The term ‘DNA’ stands for ‘de-oxy ribose nucleic acid’. It is a very long molecule and is the main component of chromosomes. DNA contains a code which, when processed by the cells’ production machinery, produces proteins. It also contains information relating to the timing and life cycle of the cell.
Refers to the relative order of base pairs in a fragment of DNA, a chromosome, a gene, or even an entire genome.
Only one copy of the allele is required in order to produce a certain characteristic. For example, if you have one allele for brown eyes and one for blue – brown is dominant and you will have brown eyes.
This is a state of abnormal muscle tone which results in both abnormal posture and muscular spasm. Dystonia typically occurs due to the presence of a neurological disease or as a side effect of drug therapy.