α

α-L-fucosidase

An enzyme acts in the lysosome. When α-L-fucosidase is deficient, fucose cannot be broken down and therefore accumulates in the body.

α-N-acetylglucosaminidase

An enzyme acts in the lysosome. α-N-acetylglucosaminidase deficiency causes heparan sulfate to accumulate in the body because it cannot be broken down.

A

Angiokeratoma

Small red pimples on the skin that are seen in some lysosomal storage diseases. It is from the bulging and keratinization of blood vessels near the epidermis.

Autosomal recessive inheritance

A form of heredity in which a disease-causing genetic abnormality is expressed in both pairs of genes on an autosomal chromosome, causing the disease to develop.

C

Chemical chaperone therapy

Medication treatment used to increase an enzyme activity to break down proteins when the misfolded protein of the enzyme is not being produced.

Compromised immunity

A condition in which resistance to disease-causing bacteria and viruses is reduced for certain reasons.

E

Enzyme activity assay

The enzyme activity assay is a test to determine the function of enzymes in the blood and cells. Lysosomal storage diseases are caused by a deficiency or weakening of enzymes that work within lysosomes. Therefore, by examining which enzymes are weakly active, the type of disease present can be diagnosed.

Enzyme replacement therapy

A method that replenishes enzymes that are lacking in the body through intravenous infusion or other means. Enzyme replacement therapy is also referred to as ERT.

G

Gene therapy

A method of treating disease-causing genetic changes by inserting normal genes from outside the body into the patient's body.

Genes

The nucleus inside of a cell contains 22 pairs (44 chromosomes) of autosomes and one pair (2 chromosomes) of sex chromosomes.
Chromosomes consist of DNA, and the areas of DNA that record structure information of specific proteins are called genes.

H

Hearing loss

Sensorineural hearing loss caused by damage to the inner ear, cochlear nerve, or brain, and conductive hearing loss caused by damage to the outer or middle ear.

Hematopoietic stem cell transplant

A medical treatment in which hematopoietic stem cells, cells which can differentiate into red blood cells, white blood cells, and platelets, are transplanted from a donor. Born marrow and umbilical cord blood transplants are performed to produce cells in the patient's body that are capable of making enzymes.

Heparan sulfate

Mucopolysaccharides are broken down in lysosomes by more than 10 different enzymes. Heparan sulfate is one of the molecules called glycosaminoglycans that accumulate in lysosomes when mucopolysaccharides are not sufficiently degraded due to either not producing enough enzymes for break down or producing enzymes that do not properly work.

Hernias

A condition in which an organ in the body protrudes from its original place. Umbilical hernia (protruding navel) and inguinal hernia (abdominal hernia) may occur in lysosomal storage diseases.

K

Kyphosis

A condition in which the spine is bent too far backward from its normal position, giving the appearance of an advanced hunchback. The condition in which the spine is bent sideways when viewed from the front is called scoliosis.

L

Lysosomal storage diseases

Many enzymes are involved in waste breakdown in lysosomes, each breaking down a different substance. These refer to a group of diseases in which the failure of any of the enzymes to break down leads accumulation of unnecessary substances in the cells and causes symptoms. Currently, 60 different diseases are included.

Lysosomes

An intracellular organelle that breaks down proteins, carbohydrates, and lipids no longer needed in the body.

N

Newborn mass screening

Testing to determine if a baby is born with a disease. Typically, a small amount of blood is drawn from the baby's heel to test for disease.

P

Psychomotor retardation

A condition in which a child is behind the age at which he or she is expected to be able to do in terms of language, learning, and motor skills as he or she grows.

S

Substrate reduction therapy

A treatment that slows down the rate at which the body generates the substance causing the lysosomal storage disease, making it less likely to accumulate in the body.