Glossary

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Amniocentesis -

Removal of a sample of amniotic fluid for prenatal testing. Cells from the unborn child can be extracted from the fluid which surrounds it in the womb and tested for certain abnormalities.

Autosomes -

All the chromosomes other than the X and Y are sex chromosomes) are known as autosomes. Autosomal inheritance means that an abnormal gene can affect either sex.

Biopsy -

Removal of a small amount of tissue for examination.

Cardiac -

To do with the heart.

Carrier -

A healthy individual who has both a normal and an abnormal copy of a pair of genes for a genetic disorder or characteristic. A carrier of a gene for a recessive disorder will usually remain unaffected throughout life.

Carrier Testing -

Tests to find out if a person who does not show symptoms of a condition nevertheless carries the gene and could pass it on to his or her children.

Cell -

The basic structural unit of all living organisms. The cell is surrounded by a membrane. Inside the cell is a structure called the nucleus. The nucleus contains DNA arranged into chromosomes.

Cell Therapy - See Myoblast Transfer Therapy.

Chorionic Villus Sampling -

(also known as CVS) - Removal of chorionic villa for prenatal testing. The chorionic villa are cells situated on the wall of the uterus (womb) which form the early placenta (afterbirth). They have the same genetic make-up as the unborn baby and can be tested to detect certain abnormalities.

Chromosomes Sausage -

shaped bundles in the cell nucleus made of a very long thin strand of the chemical molecule DNA coiled upon itself many times. Humans have 46 chromosomes (23 pairs) in most cells of their bodies. The sex cells (the unfertilized egg and sperm) contain only 23 unpaired chromosomes each. Fertilization of a 23-chromosome egg by a 23-chromosome sperm produces a new 46-chromosome cell which grows into a new individual. In this way one half of each chromosome pair is inherited from each parent.

Congenital - Present at birth or soon afterwards.

Contractures -

Shortening of muscles or tendons which prevents the associated joints from moving freely.

CPK -

Creatine Kinase. An enzyme normally present in muscle which is released into the blood when muscle is damaged. Therefore, elevated levels in blood indicate muscle (including heart muscle) has been damaged by injury or disease.

Deletion -

The loss of a bit of genetic material from a chromosome or gene.

DNA - Deoxyribonucleic Acid -

The chemical of which genes are made. it contains coded information arranged in a linear sequence. Each cell's chromosomes contain about two metres of DNA yet it is so thin that it is barely visible even with the most poweful microscope. If all the DNA in a human body were stretched end to end it would be long enough to reach the moon and back about 10,000 times.

Dominant -

In dominant inheritance if one of a pair of genes is altered the individual possessing that gene will show signs of the relevant disorder. In any pregnancy there is a 50 percent chance that he or she will pass the altered gene on giving rise to a child who is also affected.

Dystrophin -

A protein which lies under the membrane of the muscle fibre and is part of the internal cell skeleton which allows the cell to function normally. the protein that is lacking in DMD.

Duplication -

Where a part of a chromosome or gene is duplicated.

Enzyme -

A protein that accelerates chemical reactions.

Gastrostomy Tube -

a small valve that is used to feed a person who is sometimes unable to feed themselves. Can be of great value in more severe cases of CMD (Congenital Muscular Dystrophy) to ensure that a child obtains adequate fluids and food to assist in their recovery. The valve goes directly to the stomach of the person and is put in place by a minor operation.

Genes -

The coded instructions that govern the make-up of every human being. Genes are made of DNA. Each gene carries instructions for the production of a specific protein. Genes usually come in palrs one lnherited from each parent. They are passed on from one generation to the next and are the basic units of inherkance. Alterations in genes (mutations) which lead to abnormal function of the corresponding protein can cause inherited disorders.

Genetic Counselllng -

information and support provided by a specialist usually a doctor or nurse to people who have genetic conditions in their families or who are concerned about the future possibility of genetically transmuted conditions.

Genetic Disorders -

Conditions which result from alterations in the genetic make-up of an individual. They may be the consequences of defects in single genes or in whole chromosomes parts of which may be lost, duplicated or misplaced: or may result from the interaction of multiple genes and external factors.

Genetic Markers -

Harmless variations in the DNA which lie close to the site of a disrupted gene which may be used for tracking the condition through a family.

Gene Therapy -

A potential method of treatment for genetic disorders which involves making correct copies of the gene in question and then transporting them into the cells of the body.

Linkage Studies -

These are tests carried out on various family members to establish which is the crucial bit of genetic code causing a particular condition in that family.

Luque -

See "Scoliosis"

Immune Response -

The response by the body to "foreign" material (transplant or infection).

Manifesting Carrier -

A female carrier of an X-linked condition who shows symptoms.

MDX Mouse -

A mouse mutant in which the dystrophic gene is ineffective.

Myoblast -

Cell with a single nucleus which fuses with other Myoblasts to eventually form muscle fibres.

Muscle Fibre

The basic unit of muscle tissue formed by the fusion of groups of muscle cells.

Mutation -

When a gene is changed or altered in some way this is called a mutation. Mutations can be passed on to subsequent generations.

Myoblast Transfer Therapy -

A potential method of treatment for Duchenne Muscular Dystrophy which involves the transplantation of billions of healthy donor cells into muscle. This is sometimes known as cell therapy.

Nucleus -

Structure in the centre of each cell which contains the chromosomes with their genetic material.

Orthose -

Devices or aids to prevent, correct or control deformities.

Preclinical Diagnosis -

Diagnosis of a genetic disorder before there are any symptoms of that disorder.

Prednisone -

See "Steroids".

Prenatal -

Literally, before birth.

Prognosis -

Predicted course and outcome of a disorder.

Recessive -

A form of inheritance where a genetic defect causes little or no outward effect unless it is present in both of a pair of genes and has therefore been inherited from both parents. lf a person has inherited one altered gene and one normal gene he or she will not be affected but will be a gene carrier. If two carriers of the same altered gene have children in each pregnancy there is a 25 percent chance that the child will inherit two copies of the altered gene and will be affected.

Scoliosis -

Curvature of the spine.

Sex Chromosomes -

The X and Y chromosomes determine the sex of an individual. Females have two X chromosomes: males have an X and a Y chromosome.

Steroids -

These are all of a similar chemical type and include sex hormones androgens and oestrogens as well as hormones produced by the adrenal gland, the corticsteroids. There are a number of chemically modified steroids in use for muscle development.

Ultrasound -

This is a technique which uses reflected sound waves to see a hidden object. it is now widely used in medicine for example to obtain images of muscle structure and internal organs or of the unborn child.

Utrophin -

A protein related to Dystrophin with similar functions but which operates at more restricted regions of the cell. This protein is normal in DMD.

Ventilation -

Assistance in breathing by mechanically pumping air / oxygen into the lungs.

X-linked -

A form of inheritance where the gene in question lies on the X chromosome. X-linked genes can be dominant but are usually recessive. Girls who carry an altered gene are usually not affected since they have a second normal copy of the gene but they can pass the affected gene on in 50 percent of their pregnancies. Boys who have only one X chromosome do not have a second normal copy of the gene so they will be affected by the disorder in question. They will pass on the altered gene to all of their daughters who will be carriers but to none of their sons.

Additonal Research Glossary Link - Here!

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