Research Glossary


A | B | C | D | E | G | H | I | K | L | M | N | P | R | S | T | V | X |

A

Allele
One of the two possible forms of a gene (i.e. the gene from one parent).

Amino acid
A chemical compound consisting of carbon, hydrogen and oxygen atoms. They are the building blocks of proteins.

Amphyphysin 2
The protein made from the BIN1 gene. Its function is to help move other proteins around the cell.

Animal model
An organism (e.g. mouse, guinea pig, fly) which is altered in someway so as to mimic a human disease.

Antibody
A protein found in the blood which when it binds to another protein associated with disease, reduces the symptoms of the disease.

Anticodon
The complementary sequence of 3 bases against a codon. They are found in tRNA molecules. The anticodon on the tRNA binds to its codon in the mRNA bringing in the amino acid.

Antisense oligonuclotide
A chain of 10-50 nucleotides made in the laboratory which binds to a particular RNA or DNA sequence to block its expression.

Areflexia
Absence of neurologic reactions such as the knee-jerk reaction

Atom
The smallest part of a substance e.g. one hydrogen atom.

Atrophy
Wasting away of a particular tissue.

Autosome
A chromosome which is not a sex chromosome.

Autosomal dominant
A gene on a non-sex chromosome which exerts its effect when only 1 copy of the allele (i.e. from either the mother or father) is present.

Autosomal recessive
A gene on a non-sex chromosome which exerts its effect when only both alleles (i.e. from both parents) are present.


B

Base
One of the 4 units of DNA (A, T, G or C) or in RNA (A, U, G or C).

Base pair
A pair of complementary bases in DNA (A with T and G with C).

Biopsy
The surgical removal of a small piece of tissue from the human body

BIN1 gene
Mutations in this lead to autosomal recessive forms of MTM.

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C

Carrier
A person who carries one faulty copy of a gene and does not develop the full-blown disease because the disease is recessive. This can be a man or a woman for autosomal genes, but only a woman for X-linked genes.

Cell
The unit-mass of living matter. Each one consists of a central nucleus (contains DNA) and a surrounding cytoplasm (containing proteins, carbohydrates, fats and water) bound by a membrane.

Cell membrane
The outer-lining of a cell which holds all the cell contents together.

Cell model
A cell (e.g. from the skin, liver or muscle) which is altered in someway so as to mimic the fault associated with human disease.

Centronuclear myopathy (CNM)
A type of myopathy where the nuclei have moved into the centre of the muscle cells and the muscle fibres are enlarged.

Chorionic villus sampling
Removal of a small piece of tissue from a specific part of the placenta so as to analyse it both genetically and biochemically.

Chromosome
Thread-like bodies inside the nucleus which contain the DNA.

Codon
The sequence of 3 adjacent RNA bases in mRNA which codes for an amino acid.

Congenital
A feature you are born with, rather than developing later on in life.

CPAP (continuous positive airway pressure)
A method of respiratory ventilation to aid those who find normal breathing difficult whilst asleep.

Cytoplasm
The watery part of the cell surrounding the nucleus, containing the organelles such as the nucleus and mitochondria (the power factories).

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D

DNA (= deoxyribonucleic acid)
A chemical which is made up of 4 components called bases (A, T G and C) which resides in our chromosomes and in which our genes are encoded.

DNA sequence
The sequence of the 4 bases which make up DNA. Each gene has its own sequence of bases.

DNM2 gene
Mutations in this gene lead to autosomal dominant forms of MTM

Drug repurposing
The application of known drugs and compounds to new indications

Dynamin-2
Is the protein made from the DNM2 gene. Its function in the cell is to pinch off small vesicles from the cell surface.

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E

Enzyme
A protein which acts like a catalyst i.e. speeds up a reaction.

Exon
A region of a gene which encodes for part of a protein.

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G

Gain-of-function
Mutations in genes which result in a new function being assigned to the protein it encodes.

Gastrostomy tube (G-tube)
A feeding tube placed into the stomach for people who cannot eat food by swallowing.

Gene
1 part of the DNA sequence in our chromosomes which encodes for a particular protein.

Gene therapy
Treatment of a genetic disease by the addition or replacement of the affected gene with the normal gene.

Genetic counselling
This occurs in a special hospital clinic where you are provided with information on the genetic disorder you have, including the diagnosis, prognosis, risk of recurrence and options available for prevention.

Genetic markers
A DNA sequence or gene with a known location on a chromosome associated with a particular disease. It allows you to follow a disease through members of a family tree.

Genetic testing
Taking a sample of tissue for blood to test someone for the presence of genetic disease

Genetically modified organism (GMO)
An animal or a plant which has had its DNA genetically altered in someway.

Genome
The total number of genes in a cell.

Genotype
The genetic constitution of an individual.

Genotype-phenotype correlation
The relationship between a particular group of mutations and the clinical symptoms, i.e. outward appearance they produce.

Germline cells
The cells of the body which carry the genetic information onto the next generation i.e. the egg and sperm.

Germline mosaicism
The presence in the germ line cells (egg or sperm) of two populations of cells which differ genetically.

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H

Heterozygote
A person (man or woman) whose two alleles at a particular gene locus are different. If one of the alleles can cause disease, the person is said to be a carrier.

hJUMPY
The protein encoded from the MTMR14 gene. It is also known as myotubularin-related protein 14 since it is related to myotubularin. It is also able to remove phosphate from phosphoinositides.

Homozygote
A person (man or woman) whose two alleles at a particular gene locus are identical.

Human Genome Project (HGP)
An international experiment to sequence all the the DNA bases in the human genome.

Hypotonia
Lacking normal body tone i.e. floppy.

Hypertrophic
Enlarged.

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I

Intubation
Insertion of a tube, e.g. into the larynx (voice box)

Intron
A piece of DNA within a gene which does not encode for a protein.

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K

Knock-out
Complete removal of a gene from a cell or animal.

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L

Loss-of-function
The resulting phenotype from a mutation in a gene which results in either a reduced activity or total loss of the protein it encodes.

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M

Molecule
Two or more atoms bound together e.g. carbon dioxide which consists of 1 carbon atom and 2 oxygen atoms.

Morpholino antisense oligonucleotide
A type of antisense oligonucleotide that has been chemically modified so as to not be degraded by the body’s natural defence mechanisms.

mRNA (= message RNA)
A nucleic acid chemical made up of ribonucleic acid bases (A, U, G and C). Each mRNA is made from a specific DNA molecule i.e. from one gene, and is then used to make the protein that gene encodes for.

MTM1 gene
Encodes for the protein myotubularin. This protein removes phosphates from phosphoinositides. Mutations in this gene cause X-linked MTM.

MTMR14 gene
Mutations in this gene cause sporadic cases of CNM.

Mutation
A change in the genetic material (DNA) either in 1 gene, or in an entire chromosome. There are many different types of mutations:
Point- a mutation affecting just 1 base.
Deletion – removal of 1 or more bases
Missense – a change so the amino acid sequence is changed in the protein
Nonsense – a change so the amino acid is changed to a stop codon
Frameshift (or out of frame)- a change so the reading frame of the mRNA is altered.

Mutagen
A reagent which causes a mutation e.g. a chemical, ultra-violet radiation.

Myopathies
Degenerative muscle diseases.

Myoblast
One muscle cell.

Myotube
A tube of myoblasts which have fused as an early stage of muscle fibre formation.

Myofibril
Bundles of filaments consisting of the proteins myosin and actin which run the length of muscle cells and provide the force of contraction

Myofibre
Part of a large muscle; a large collection of myofibrils.

Myotubularin
The protein which is dysfunctional in X-linked MTM patients. This protein is an enzyme which acts to remove phosphates off a type of fat molecule called phosphoinositides.

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N

Nucleus
A rounded structure within a cell which contains the chromosomes i.e. our genetic material.

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P

Phase I, II and II clinical trials
Medical testing for a drug which progresses from Phase I through to III as the number of patients being treated in the trial increases. So Phase I is 10 patients or less, where the safety, dosage, side-effects of the treatment are monitored. Phase 2 involves 20-300 people and re-evaluates for the same conditions. There are also Phase IIA and IIB classifications, where IIA concentrates on looking at different drug doses and IIB the efficacy of the drug at those doses. Phase III involves over 300 patients and is normally organised at an international level.

Pedigree
Line of ancestors which makes up your family tree.

Phenotype
The appearance of an individual which comes about from the interaction of the environment with their genetic make-up.

Pre-clinical
In drug development, pre-clinical development, also named preclinical studies and nonclinical studies, is a stage of research that begins before clinical trials (testing in humans) can begin, and during which important feasibility, iterative testing and drug safety data is collected.

After preclinical testing, researchers review their findings and decide whether the drug should be tested in people.

Prognosis
Making a forecast as to how a disease will progress with time.

Phosphoinositides
A special type of fat which had phosphate attached to it.

Polymerase Chain Reaction (PCR)
An experimental technique for increasing the amount of DNA or RNA present in a tissue sample e.g. from 1 strand of hair, so as to obtain enough DNA/RNA to analyse it.

Promoter
A special type of DNA sequence at the beginning of a gene which regulates the expression of that gene.

Protein
A chemical found in our cells made up of components known as amino acids. Proteins make us what we are.

Ptosis
Droopy eyelids

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R

Reading frame
The order of the codons encoding for the amino acids in the mRNA molecule.

Ribosome
Small round structures inside the cell which are needed to make proteins.

RYR1 gene
This encodes for a protein called the ryanodine receptor, a large protein which is in the T-tubule network and is involved in moving calcium around the muscle. Mutations in this gene are associated with autosomal dominant CNM.

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S

Sarcolemma
The cell surface of a muscle cell.

Scoliosis
Curvature of the spine.

Sex chromosome
The so-called X and Y chromosomes. These are not autosomes and are important for determining whether we are male or female. To be female you need an X-chromosome from each parent (i.e. be XX), and to be male you need an X-chromosome from your mother and a Y chromosome from your father (i.e. be XY).

Signalling pathway
A route inside cells which passes through many different chemicals so as to take a message from one side of the cell to the other.

SMarT
This is where two different RNA molecules are combined or ‘spliced’ to generate a new one. One of these RNA molecules is the one inside the patient cells encoding for the faulty gene – in the case of MTM/CNM the DNM2 gene - and the other encodes for the normal gene and is introduced into the cells using a vector. This second RNA molecule is made in the laboratory and is known as a RNA pre-transplicing molecule (PTM). When the two RNA molecules are ‘spliced’ the faulty part of the DNM2 gene in the patient’s cells is ‘cut’ out and the normal copy from the introduced vector ‘pasted’ in. The result is that the patient cells have had their faulty RNA molecule reprogrammed to encode a healthier version of the protein. The advantage of this gene therapy technique over others is that the production of the reprogrammed RNA molecule is under direct control of signalling processes associated with the patient’s cells, rather than from external factors which are less easy to control.

SMarT is the latest gene therapy technology likely to be applicable to ALL autosomal dominant diseases, not just those affecting muscle, and so has wide implications for treating genetic diseases in general.

Sporadic mutation
A new mutation in an individual which was not inherited from either parent.

Stop (or termination) codons
A codon in the MRNA which tells the cell to stop making a particular protein. No more amino acids are added

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T

Telomere
The end of a chromosome

Tissue
A collection of different types of cells making up a particular organ e.g. liver, muscle, brain

t-RNA
A special type of RNA molecule which carries amino acids to the mRNA molecules.

Transgenic
A technique for introducing another gene or a mutation into a gene so as to study a particular disease or signalling pathway.

Translation
The process of making proteins from mRNA molecule.

Transcription
The process of making mRNA from a DNA molecule.

T-tubule
A connecting series of pipes in a hair-net formation which lies over the surface of a muscle fibre. It contains calcium which is needed for muscles to contract.

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V

Vector
A vehicle for moving the gene you are studying between different cells in order to characterise its function e.g. a virus or a plasmid.

Vesicles
Small sacs inside cells which store and transport chemicals e.g. nutrients, waste products around the cell.

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X

X-linked
Genes on the X-chromosome associated with disease. X-linked recessive means that females are carriers of the disease and that males develop the disease.

X-linked myotubular myopathy (MTM)
The most severe form of centonuclear myopathy.

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