An enzyme that breaks down a particular type of fatty substances, Fabry disease is characterized by its absence.

An enzyme that breaks down a particular type of fatty substances, Pompe disease is characterized by its absence.

A procedure used for prenatal diagnosis, which involves insertion of a needle through the abdomen into the amniotic fluid. This procedure is performed using ultrasound guidance, and allows the physician to obtain a small amount of amniotic fluid which can then be used for testing. Amniocentesis is usually performed between 16 and 18 weeks of pregnancy, but some centers offer “early amnio” at 14 weeks of pregnancy.

Amniotic fluid is the nursing and protecting contained by the amniotic sac. It is used for genetic screening of the fetus.

Angiokeratomas are small dark red to purple raised spots. They may also have a rough scaly surface. They are composed of surface blood vessels (dilated capillaries). Often unnoticed, they may become crusty and bleed if accidentally scratched or damaged, or a harmless clot may form in the lesion (thrombosis), changing the color to dark purple or black overnight.

An enzyme that breaks down a N-acetylaspartate acid into parts thought to be necessary for proper myelin production and maintenance, Canavan disease is characterized by its absence.

The inhalation of either food or stomach contents into the lower airways. This can lead to aspiration pneumonia and aspiration pneumonitis. Although these two diagnoses are managed differently, they are often interchangeably referred to as aspiration pneumonia.

Lack of coordination

An inability to coordinate voluntary muscular movements that is symptomatic of some nervous disorders.

Definition from: http://www.m-w.com/ by Merriam-Webster Inc.

Wasting away or diminution. Muscle atrophy is wasting of muscle, decrease in muscle mass.

A nerve can also show atrophy. For example, atrophy of the optic nerve diminishes vision.

Definition from: http://www.medicinenet.com/script/main/hp.asp by MedicineNet Inc.

Refers to genes that are not found on the sex chromosomes. Those chromosomes that are not XX and XY, i.e. sex-linked.

Describes a trait or disorder requiring the presence of two copies of a gene mutation at a particular locus in order to express observable phenotype; specifically refers to genes on one of the 22 pairs of autosomes (non-sex chromosomes)

A network of blood vessels with closely spaced cells that makes it difficult for potentially toxic substances (such as anticancer drugs) to penetrate the blood vessel walls and enter the brain.

Definition from: Unified Medical Language System

A naturally occurring barrier created by the modification of brain capillaries (as by reduction in fenestration and formation of tight cell-to-cell contacts) that prevents many substances from leaving the blood and crossing the capillary walls into the brain tissues -- abbreviation BBB.

Definition from: Merriam-Webster’s Medical Dictionary http://www.m-w.com/

Abnormal enlargement of the heart.

Carrier testing can determine if a person carries one of the altered genes that cause a recessive disease. DNA carrier testing establishes the presences or absences of particular mutation(s). Enzymatic testing evaluates the level of activity of an enzyme, which when absent causes disease. In some diseases the enzyme test is not sensitive enough to determine carrier status.

The central nervous system is that part of the nervous system that consists of the brain and spinal cord. The central nervous system (CNS) is one of the two major divisions of the nervous system. The other is the peripheral nervous system (PNS) which is outside the brain and spinal cord. The peripheral nervous system (PNS) connects the central nervous system (CNS) to sensory organs (such as the eye and ear), other organs of the body, muscles, blood vessels and glands. The peripheral nerves include cranial nerves, spinal nerves and roots, and what are called the autonomic nerves that are concerned specifically with the regulation of the heart muscle, the muscles in blood vessel walls, and glands.

The term ‘cherry red spot’ describes the appearance of the retina when viewed by an eye specialist that is associated with metabolic neurological disorders like Tay-Sachs, Sandhoff, GM-1, Niemann-Pick, MPS and other similar disorders. Warren Tay described the cherry red spot in Symmetrical changes in the region of the yellow spot in each eye of an infant, published in Transactions of Ophthalmology Society UK in 1881: …in the region of the yellow spot in each eye there was a conspicuous, tolerably defined, large white patch, more or less circular in outline, and showing at its centre a brownish-red, fairly circular spot, contrasting strongly wit the white patch surrounding it.

Disappearance of the cherry-red spot is not indictiative of disease lessening.

Endoplasmic reticulum and Enzyme definitions are swapped.

A procedure used for prenatal diagnosis, which involves insertion of a needle through the abdomen into fingerlike projections of the placenta which are called chorionic villi. This procedure is also performed using ultrasound guidance, and testing can be performed with the tissue obtained. Depending upon the location of the placenta, the tissue may be obtained transvaginally rather than abdominally, by inserting a catheter through the cervix and into the uterus. CVS is usually performed at 10 to 12 weeks of pregnancy.

Structures found in the nucleus of the cell, which are visible under a microscope and which contain genetic (inherited) information. Human cells contain 46 chromosomes, which come in pairs. There are twenty-two pairs of chromosomes which are referred to as autosomes, because they do not determine the sex of an individual. The twenty-third pair are referred to as the sex chromosomes, and are called the X and Y chromosomes. Each chromosome contains thousands of individual genes, which will in turn determine an individual’s characteristics.

Short noses, flat faces and large head is often described as coarsening of facial features

Organized carrier testing outreach events to educate high risk ethic groups on the importance of genetic screening and to provide convenient free or reduced cost testing.

The study of human chromosomes.

The chemical sequence found in genes, and which allows for the transmission of inherited information from generation to generation.

Points away from the center of the body. Distal muscles are in the limbs, opposite of proximal

For more details visit http://www.nlm.nih.gov/medlineplus/ency/article/002346.htm

alternate names: Swollen belly; Swelling in the abdomen; Abdominal distention Distended abdomen may be cause by variety of reason, in the allied disease it is typically caused by, the enlargement of the liver and spleen, also called hepatosplenomegaly.

DNA analysis looks for particular or known mutations in the genome or genetic make up.

A pattern of inheritance whereby a single gene mutation may lead to a specific genetic disease. Children of an individual affected with a dominantly inherited condition (often referred to as autosomal dominant if the gene is not located on the X or Y chromosomes) have a 50% chance to inherit the gene mutation.

Speech that is characteristically slurred, slow, and difficult to produce (difficult to understand). The person with dysarthria may also have problems controlling the pitch, loudness, rhythm, and voice qualities of their speech. Definition from: http://www.medterms.com/script/main/art.asp?articlekey=11180

A substance that in small amounts increases the rate of a specific biochemical reaction. Often enzymes are required for the normal metabolism, or breakdown, of substances in the body.

A complex pipe-like system of membranes that occupies much of the cytoplasm in cells and which contains many of the enzymes which are responsible for the breakdown of metabolic waste into reuse able parts

Measurement of enzyme activity with particular substrate, for example an enzyme assay for Tay-Sachs disease measures the Hex A activity with GM2 gangliosides.

Muscle twitches are fine or tiny uncontrollable movements of a small area of muscles. Some are common while others are associated with neurological disease.

For more details visit: http://www.nlm.nih.gov/medlineplus/ency/article/003296.htm

Any of a group of glycolipids that yield a hexose sugar on hydrolysis and are found especially in the plasma membrane of cells of the gray matter.

Definition from: Merriam-Webster’s Medical Dictionary http://www.m-w.com/ by Merriam-Webster Inc.

Often referred to as the “unit of heredity.” A gene is composed of a sequence of DNA required to produce a functional protein.

As defined by the National Society of Genetic Counselors, is the process of helping people understand and adapt to the medical, psychological and familial implications of genetic contributions to disease. This process integrates:

-Interpretation of family and medical histories to assess the chance of disease occurrence or recurrence.

-Education about inheritance, testing, management, prevention, resources and research.

-Counseling to promote informed choices and adaptation to the risk or condition.

The glucocerebrodidase enzyme is necessary for the breakdown of a particular fatty substance, glucocerebroside into glucose and ceramide. Gaucher disease is characterized by its absence.

A type of fat (lipid) molecule accumulates in individuals with Gaucher disease and is used as a building block to make certain cell membranes. When the cells wear out, the glucocerebroside can be recycled. This recyclable material comes mainly from the breakdown of old red and white blood cells. In the brain, glucocerebroside comes from the processing of lipids during brain development and the formation of the myelin sheath (the fatty coating around each nerve fiber).

Simple sugar; the form in which all carbohydrates are used as the body's principal energy source; transported in the blood and metabolized in the tissues.

Form in which foods are stored in the body as energy.

A class of disorders characterized by the build-up of glycogen causes progressive muscle weakness throughout the body and affects various body tissues, particularly in the heart, skeletal muscles, liver, and nervous system.

A fatty substance or lipid that is part of normal metabolism, in Tay-Sachs and Sandhoff lack of enzyme function causes the GM2 gangliosides to accumulate which is toxic and eventually causes cell death.

Tay-Sachs and Sandhoff are known collectively as GM2.

Tay-Sachs is caused by a mutation in the Hex A gene on chromosome 15. The Hex A gene codes for the alpha subunit of the hexosaminidase A enzyme which is necessary for breaking down GM2 gangliosides in nerve cells. When there is a mutation in the coding for alpha subunit of the hexosaminidase A it does not function properly and leads to an accumulation of GM2 which is toxic and eventually causes cell death. Sandhoff is characterized by loss of function of both the alpha and beta subunit of hexosaminidase A enzyme. For more information visit: http://ghr.nlm.nih.gov/gene=hexa

Sandhoff is caused by a mutation in the Hex B gene on chromosome 5. The Hex B gene codes for part of two essential nervous system enzymes: the beta subunit of hexosaminidase A and the beta subunit of hexosaminidase B. When there is a mutation in the coding for beta subunit of hexosaminidase A and the beta subunit of hexosaminidase B both enzymes do not function properly and lead to an accumulation of GM2 which is toxic and eventually causes cell death. Tay-Sachs is characterized by loss of function of only the alpha subunit of the hexosaminidase A enzyme. For more information: http://ghr.nlm.nih.gov/gene=hexb

Decreased muscle tone, limpness.

Allied diseases often interfere with muscle control and subsequent joint movement leading to stiffness and reduced range of motion.

A group of rare genetic disorders that affect the central nervous system by disrupting the growth or maintenance of the myelin sheath that insulates nerve cells. Myelin is commonly referred to as the brain’s “white matter,” myelin covers nerve cells and ensures the clear transmission of nerve impulses from one part of the body to another. These disorders are progressive, meaning that they tend to get worse throughout the life of the patient.

The word leukodystrophy comes from the Greek words leuko (meaning white), trophy (meaning growth), and dys (meaning ill). If you put these words together, the word leukodystrophy describes a set of diseases that affect the growth or maintenance of the white matter (myelin).

Linkage is the tendency for genes and other genetic markers to be inherited together because of their location near one another on the same chromosomes. Linkage analysis uses the location relationship to determine carrier status of particular genes.

Large and complicated reddish-brown glandular organ located in the upper right portion of the abdominal cavity; secretes bile and functions in metabolism of protein and carbohydrate and fat; synthesizes substances involved in the clotting of the blood; synthesizes vitamin A; detoxifies poisonous substances and breaks down worn-out red blood cells. Definitions from: WordNet®

Is a combination of two fats extracted from olive oil and rapeseed oil and is specific to adrenoleukodystrophy (ALD), does not repair myelin, and does not have any known effect on other demyelinating disorders. In ALD presymptomatic boys Lorenzo’s Oil often (but not always) prevents the onset of the disease by stopping the body from producing the very long chain fatty acids, whose buildup leads to demyelination. For more information visit the Myelin Project

Organelle structures found within the cytoplasm of cells which contain digestive enzymes; responsible for breaking down the cell of debris into reusable parts.

Depression in bipolar disorder is a mood disorder characterized by mood swings from mania (exaggerated feeling of well-being, energy, and confidence in which a person can lose touch with reality) to depression with the current or most recent episode of illness characterized by depression. For more details visit: http://www.nlm.nih.gov/medlineplus/ency/article/000927.htm