Wolfram syndrome
Encyclopedia
Wolfram syndrome, also called DIDMOAD (Diabetes Insipidus, Diabetes Mellitus, Optic Atrophy, and Deafness), is a rare genetic disorder
Genetic disorder
A genetic disorder is an illness caused by abnormalities in genes or chromosomes, especially a condition that is present from before birth. Most genetic disorders are quite rare and affect one person in every several thousands or millions....

, causing diabetes mellitus
Diabetes mellitus
Diabetes mellitus, often simply referred to as diabetes, is a group of metabolic diseases in which a person has high blood sugar, either because the body does not produce enough insulin, or because cells do not respond to the insulin that is produced...

, optic atrophy, and deafness as well as various other possible disorders.

It was first described in four siblings in 1938 by Dr. Don J. Wolfram, M.D.
The disease affects the brain
Brain
The brain is the center of the nervous system in all vertebrate and most invertebrate animals—only a few primitive invertebrates such as sponges, jellyfish, sea squirts and starfishes do not have one. It is located in the head, usually close to primary sensory apparatus such as vision, hearing,...

 (especially the brain stem) and central nervous system
Central nervous system
The central nervous system is the part of the nervous system that integrates the information that it receives from, and coordinates the activity of, all parts of the bodies of bilaterian animals—that is, all multicellular animals except sponges and radially symmetric animals such as jellyfish...

.

Causes

It is thought to be caused by both a malfunction of the mitochondria and of myelin
Myelin
Myelin is a dielectric material that forms a layer, the myelin sheath, usually around only the axon of a neuron. It is essential for the proper functioning of the nervous system. Myelin is an outgrowth of a type of glial cell. The production of the myelin sheath is called myelination...

ation, the latter in effect similar to multiple sclerosis
Multiple sclerosis
Multiple sclerosis is an inflammatory disease in which the fatty myelin sheaths around the axons of the brain and spinal cord are damaged, leading to demyelination and scarring as well as a broad spectrum of signs and symptoms...

. It may have autosomal recessive or dominant or mitochondrial inheritance depending on the genes involved.

Three genetic forms have been described: Wolfram Syndrome 1 (WFS1), Wolfram Syndrome 2 (WFS2) and a possible mitochondrial syndrome.

WFS1

The WFS1
WFS1
Wolframin is a protein that in humans is encoded by the WFS1 gene.-Function:Wolframin is a transmembrane protein. Wolframin appears to function as a cation-selective ion channel.-Clinical significance:...

 or wolframin gene provides instructions for making the wolframin protein. The WFS1 gene is active in cells throughout the body, with strong activity in the heart, brain, lungs, inner ear, and pancreas. The pancreas provides enzymes that help digest food, and it also produces the hormone insulin. Insulin controls how much glucose (a type of sugar) is passed from the blood into cells for conversion to energy.

Within cells, wolframin is located in a structure called the endoplasmic reticulum. Among its many activities, the endoplasmic reticulum folds and modifies newly formed proteins so they have the correct 3-dimensional shape to function properly. The endoplasmic reticulum also helps transport proteins, fats, and other materials to specific sites within the cell or to the cell surface. The function of wolframin is unknown. Based on its location in the endoplasmic reticulum, however, it may play a role in protein folding or cellular transport. In the pancreas, wolframin may help fold a protein precursor of insulin (called proinsulin) into the mature hormone that controls blood glucose levels. Research findings also suggest that wolframin may help maintain the correct cellular level of charged calcium atoms (calcium ions) by controlling how much is stored in the endoplasmic reticulum. In the inner ear, wolframin may help maintain the proper levels of calcium ions or other charged particles that are essential for hearing.

More than 30 WFS1 mutations have been identified in individuals with a form of nonsyndromic deafness (hearing loss without related signs and symptoms affecting other parts of the body) called DFNA6. Individuals with DFNA6 deafness cannot hear low tones (low-frequency sounds), such as a tuba or the "m" in moon. DFNA6 hearing loss is unlike most forms of nonsyndromic deafness that affect high tones (high-frequency sounds), such as birds chirping, or all frequencies of sound. Most WFS1 mutations replace one of the protein building blocks (amino acids) used to make wolframin with an incorrect amino acid. One mutation deletes an amino acid from wolframin. WFS1 mutations probably alter the 3-dimensional shape of wolframin, which could affect its function. Because the function of wolframin is unknown, however, it is unclear how WFS1 mutations cause hearing loss. Some researchers suggest that altered wolframin disturbs the balance of charged particles in the inner ear, which interferes with the hearing process.

Other disorders - caused by mutations in the WFS1 gene

Mutations in the WFS1 gene cause Wolfram syndrome, which is also known by the acronym DIDMOAD. This syndrome is characterised by childhood-onset diabetes mellitus (DM), which results from the improper control of glucose due to the lack of insulin; a gradual loss of vision caused by optic atrophy (OA), in which the nerve that connects the eye to the brain wastes away; and deafness (D). This syndrome can sometimes cause diabetes insipidus (DI), a condition in which the kidneys cannot conserve water. Other complications that affect the bladder and nervous system may also occur.

Researchers have identified more than 100 WFS1 mutations that cause Wolfram syndrome. Some mutations delete or insert DNA from the WFS1 gene. As a result, little or no wolframin is present in cells. Other mutations replace one of the protein building blocks (amino acids) used to make wolframin with an incorrect amino acid. These mutations appear to reduce wolframin activity dramatically. Researchers suggest that the loss of wolframin disrupts the production of insulin, which leads to poor glucose control and diabetes mellitus. It is unclear how WFS1 mutations lead to other features of Wolfram syndrome.

Prognosis

Life expectancy of people suffering from this syndrome is about 30 years.
Wolfram syndrome, also called DIDMOAD (Diabetes Insipidus, Diabetes Mellitus, Optic Atrophy, and Deafness), is a rare genetic disorder
Genetic disorder
A genetic disorder is an illness caused by abnormalities in genes or chromosomes, especially a condition that is present from before birth. Most genetic disorders are quite rare and affect one person in every several thousands or millions....

, causing diabetes mellitus
Diabetes mellitus
Diabetes mellitus, often simply referred to as diabetes, is a group of metabolic diseases in which a person has high blood sugar, either because the body does not produce enough insulin, or because cells do not respond to the insulin that is produced...

, optic atrophy, and deafness as well as various other possible disorders.

It was first described in four siblings in 1938 by Dr. Don J. Wolfram, M.D.
The disease affects the brain
Brain
The brain is the center of the nervous system in all vertebrate and most invertebrate animals—only a few primitive invertebrates such as sponges, jellyfish, sea squirts and starfishes do not have one. It is located in the head, usually close to primary sensory apparatus such as vision, hearing,...

 (especially the brain stem) and central nervous system
Central nervous system
The central nervous system is the part of the nervous system that integrates the information that it receives from, and coordinates the activity of, all parts of the bodies of bilaterian animals—that is, all multicellular animals except sponges and radially symmetric animals such as jellyfish...

.

Causes

It is thought to be caused by both a malfunction of the mitochondria and of myelin
Myelin
Myelin is a dielectric material that forms a layer, the myelin sheath, usually around only the axon of a neuron. It is essential for the proper functioning of the nervous system. Myelin is an outgrowth of a type of glial cell. The production of the myelin sheath is called myelination...

ation, the latter in effect similar to multiple sclerosis
Multiple sclerosis
Multiple sclerosis is an inflammatory disease in which the fatty myelin sheaths around the axons of the brain and spinal cord are damaged, leading to demyelination and scarring as well as a broad spectrum of signs and symptoms...

. It may have autosomal recessive or dominant or mitochondrial inheritance depending on the genes involved.

Three genetic forms have been described: Wolfram Syndrome 1 (WFS1), Wolfram Syndrome 2 (WFS2) and a possible mitochondrial syndrome.

WFS1

The WFS1
WFS1
Wolframin is a protein that in humans is encoded by the WFS1 gene.-Function:Wolframin is a transmembrane protein. Wolframin appears to function as a cation-selective ion channel.-Clinical significance:...

 or wolframin gene provides instructions for making the wolframin protein. The WFS1 gene is active in cells throughout the body, with strong activity in the heart, brain, lungs, inner ear, and pancreas. The pancreas provides enzymes that help digest food, and it also produces the hormone insulin. Insulin controls how much glucose (a type of sugar) is passed from the blood into cells for conversion to energy.

Within cells, wolframin is located in a structure called the endoplasmic reticulum. Among its many activities, the endoplasmic reticulum folds and modifies newly formed proteins so they have the correct 3-dimensional shape to function properly. The endoplasmic reticulum also helps transport proteins, fats, and other materials to specific sites within the cell or to the cell surface. The function of wolframin is unknown. Based on its location in the endoplasmic reticulum, however, it may play a role in protein folding or cellular transport. In the pancreas, wolframin may help fold a protein precursor of insulin (called proinsulin) into the mature hormone that controls blood glucose levels. Research findings also suggest that wolframin may help maintain the correct cellular level of charged calcium atoms (calcium ions) by controlling how much is stored in the endoplasmic reticulum. In the inner ear, wolframin may help maintain the proper levels of calcium ions or other charged particles that are essential for hearing.

More than 30 WFS1 mutations have been identified in individuals with a form of nonsyndromic deafness (hearing loss without related signs and symptoms affecting other parts of the body) called DFNA6. Individuals with DFNA6 deafness cannot hear low tones (low-frequency sounds), such as a tuba or the "m" in moon. DFNA6 hearing loss is unlike most forms of nonsyndromic deafness that affect high tones (high-frequency sounds), such as birds chirping, or all frequencies of sound. Most WFS1 mutations replace one of the protein building blocks (amino acids) used to make wolframin with an incorrect amino acid. One mutation deletes an amino acid from wolframin. WFS1 mutations probably alter the 3-dimensional shape of wolframin, which could affect its function. Because the function of wolframin is unknown, however, it is unclear how WFS1 mutations cause hearing loss. Some researchers suggest that altered wolframin disturbs the balance of charged particles in the inner ear, which interferes with the hearing process.

Other disorders - caused by mutations in the WFS1 gene

Mutations in the WFS1 gene cause Wolfram syndrome, which is also known by the acronym DIDMOAD. This syndrome is characterised by childhood-onset diabetes mellitus (DM), which results from the improper control of glucose due to the lack of insulin; a gradual loss of vision caused by optic atrophy (OA), in which the nerve that connects the eye to the brain wastes away; and deafness (D). This syndrome can sometimes cause diabetes insipidus (DI), a condition in which the kidneys cannot conserve water. Other complications that affect the bladder and nervous system may also occur.

Researchers have identified more than 100 WFS1 mutations that cause Wolfram syndrome. Some mutations delete or insert DNA from the WFS1 gene. As a result, little or no wolframin is present in cells. Other mutations replace one of the protein building blocks (amino acids) used to make wolframin with an incorrect amino acid. These mutations appear to reduce wolframin activity dramatically. Researchers suggest that the loss of wolframin disrupts the production of insulin, which leads to poor glucose control and diabetes mellitus. It is unclear how WFS1 mutations lead to other features of Wolfram syndrome.

Prognosis

Life expectancy of people suffering from this syndrome is about 30 years.
Wolfram syndrome, also called DIDMOAD (Diabetes Insipidus, Diabetes Mellitus, Optic Atrophy, and Deafness), is a rare genetic disorder
Genetic disorder
A genetic disorder is an illness caused by abnormalities in genes or chromosomes, especially a condition that is present from before birth. Most genetic disorders are quite rare and affect one person in every several thousands or millions....

, causing diabetes mellitus
Diabetes mellitus
Diabetes mellitus, often simply referred to as diabetes, is a group of metabolic diseases in which a person has high blood sugar, either because the body does not produce enough insulin, or because cells do not respond to the insulin that is produced...

, optic atrophy, and deafness as well as various other possible disorders.

It was first described in four siblings in 1938 by Dr. Don J. Wolfram, M.D.
The disease affects the brain
Brain
The brain is the center of the nervous system in all vertebrate and most invertebrate animals—only a few primitive invertebrates such as sponges, jellyfish, sea squirts and starfishes do not have one. It is located in the head, usually close to primary sensory apparatus such as vision, hearing,...

 (especially the brain stem) and central nervous system
Central nervous system
The central nervous system is the part of the nervous system that integrates the information that it receives from, and coordinates the activity of, all parts of the bodies of bilaterian animals—that is, all multicellular animals except sponges and radially symmetric animals such as jellyfish...

.

Causes

It is thought to be caused by both a malfunction of the mitochondria and of myelin
Myelin
Myelin is a dielectric material that forms a layer, the myelin sheath, usually around only the axon of a neuron. It is essential for the proper functioning of the nervous system. Myelin is an outgrowth of a type of glial cell. The production of the myelin sheath is called myelination...

ation, the latter in effect similar to multiple sclerosis
Multiple sclerosis
Multiple sclerosis is an inflammatory disease in which the fatty myelin sheaths around the axons of the brain and spinal cord are damaged, leading to demyelination and scarring as well as a broad spectrum of signs and symptoms...

. It may have autosomal recessive or dominant or mitochondrial inheritance depending on the genes involved.

Three genetic forms have been described: Wolfram Syndrome 1 (WFS1), Wolfram Syndrome 2 (WFS2) and a possible mitochondrial syndrome.

WFS1

The WFS1
WFS1
Wolframin is a protein that in humans is encoded by the WFS1 gene.-Function:Wolframin is a transmembrane protein. Wolframin appears to function as a cation-selective ion channel.-Clinical significance:...

or wolframin gene provides instructions for making the wolframin protein. The WFS1 gene is active in cells throughout the body, with strong activity in the heart, brain, lungs, inner ear, and pancreas. The pancreas provides enzymes that help digest food, and it also produces the hormone insulin. Insulin controls how much glucose (a type of sugar) is passed from the blood into cells for conversion to energy.

Within cells, wolframin is located in a structure called the endoplasmic reticulum. Among its many activities, the endoplasmic reticulum folds and modifies newly formed proteins so they have the correct 3-dimensional shape to function properly. The endoplasmic reticulum also helps transport proteins, fats, and other materials to specific sites within the cell or to the cell surface. The function of wolframin is unknown. Based on its location in the endoplasmic reticulum, however, it may play a role in protein folding or cellular transport. In the pancreas, wolframin may help fold a protein precursor of insulin (called proinsulin) into the mature hormone that controls blood glucose levels. Research findings also suggest that wolframin may help maintain the correct cellular level of charged calcium atoms (calcium ions) by controlling how much is stored in the endoplasmic reticulum. In the inner ear, wolframin may help maintain the proper levels of calcium ions or other charged particles that are essential for hearing.

More than 30 WFS1 mutations have been identified in individuals with a form of nonsyndromic deafness (hearing loss without related signs and symptoms affecting other parts of the body) called DFNA6. Individuals with DFNA6 deafness cannot hear low tones (low-frequency sounds), such as a tuba or the "m" in moon. DFNA6 hearing loss is unlike most forms of nonsyndromic deafness that affect high tones (high-frequency sounds), such as birds chirping, or all frequencies of sound. Most WFS1 mutations replace one of the protein building blocks (amino acids) used to make wolframin with an incorrect amino acid. One mutation deletes an amino acid from wolframin. WFS1 mutations probably alter the 3-dimensional shape of wolframin, which could affect its function. Because the function of wolframin is unknown, however, it is unclear how WFS1 mutations cause hearing loss. Some researchers suggest that altered wolframin disturbs the balance of charged particles in the inner ear, which interferes with the hearing process.

Other disorders - caused by mutations in the WFS1 gene

Mutations in the WFS1 gene cause Wolfram syndrome, which is also known by the acronym DIDMOAD. This syndrome is characterised by childhood-onset diabetes mellitus (DM), which results from the improper control of glucose due to the lack of insulin; a gradual loss of vision caused by optic atrophy (OA), in which the nerve that connects the eye to the brain wastes away; and deafness (D). This syndrome can sometimes cause diabetes insipidus (DI), a condition in which the kidneys cannot conserve water. Other complications that affect the bladder and nervous system may also occur.

Researchers have identified more than 100 WFS1 mutations that cause Wolfram syndrome. Some mutations delete or insert DNA from the WFS1 gene. As a result, little or no wolframin is present in cells. Other mutations replace one of the protein building blocks (amino acids) used to make wolframin with an incorrect amino acid. These mutations appear to reduce wolframin activity dramatically. Researchers suggest that the loss of wolframin disrupts the production of insulin, which leads to poor glucose control and diabetes mellitus. It is unclear how WFS1 mutations lead to other features of Wolfram syndrome.

External links

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