Menkes disease
Overview
 
Menkes disease also called Menkes syndrome, copper transport disease, steely hair disease, kinky hair disease, or Menkes kinky hair syndrome, is a disorder that affects copper
Copper
Copper is a chemical element with the symbol Cu and atomic number 29. It is a ductile metal with very high thermal and electrical conductivity. Pure copper is soft and malleable; an exposed surface has a reddish-orange tarnish...

 levels in the body, leading to copper deficiency. It is an x-linked recessive
X-linked recessive
X-linked recessive inheritance is a mode of inheritance in which a mutation in a gene on the X chromosome causes the phenotype to be expressed in males and in females who are homozygous for the gene mutation X-linked recessive inheritance is a mode of inheritance in which a mutation in a gene on...

 disorder, and is therefore considerably more common in males: females require two defective alleles to develop the disease.

The disorder was originally described by John Hans Menkes et al. in 1962.
MNK is characterized by sparse and coarse hair, growth failure, and deterioration of the nervous system.
Encyclopedia
Menkes disease also called Menkes syndrome, copper transport disease, steely hair disease, kinky hair disease, or Menkes kinky hair syndrome, is a disorder that affects copper
Copper
Copper is a chemical element with the symbol Cu and atomic number 29. It is a ductile metal with very high thermal and electrical conductivity. Pure copper is soft and malleable; an exposed surface has a reddish-orange tarnish...

 levels in the body, leading to copper deficiency. It is an x-linked recessive
X-linked recessive
X-linked recessive inheritance is a mode of inheritance in which a mutation in a gene on the X chromosome causes the phenotype to be expressed in males and in females who are homozygous for the gene mutation X-linked recessive inheritance is a mode of inheritance in which a mutation in a gene on...

 disorder, and is therefore considerably more common in males: females require two defective alleles to develop the disease.

The disorder was originally described by John Hans Menkes et al. in 1962.

Characteristics

MNK is characterized by sparse and coarse hair, growth failure, and deterioration of the nervous system. Onset of Menkes syndrome typically begins during infancy. Signs and symptoms of this disorder include weak muscle tone (hypotonia), sagging facial features, seizures, mental retardation, and developmental delay. The patients have brittle hair and metaphyseal widening. In rare cases, symptoms begin later in childhood and are less severe. Affected infants may be born prematurely. Symptoms appear during infancy and are largely a result of abnormal intestinal copper absorption with secondary deficiency in copper-dependent mitochondrial enzymes. Normal or slightly slowed development may proceed for 2 to 3 months, and then there will be severe developmental delay and a loss of early developmental skills. Menkes Disease is also characterized by seizure
Seizure
An epileptic seizure, occasionally referred to as a fit, is defined as a transient symptom of "abnormal excessive or synchronous neuronal activity in the brain". The outward effect can be as dramatic as a wild thrashing movement or as mild as a brief loss of awareness...

s, failure to thrive
Failure to thrive
Failure to thrive is a medical term which is used in both pediatric and adult human medicine, as well as veterinary medicine ....

, subnormal body temperature, and strikingly peculiar hair, which is kinky, colorless or steel-colored, and easily broken. There can be extensive neurodegeneration in the gray matter of the brain. Arteries in the brain can also be twisted with frayed and split inner walls. This can lead to rupture or blockage of the arteries. Weakened bones (osteoporosis
Osteoporosis
Osteoporosis is a disease of bones that leads to an increased risk of fracture. In osteoporosis the bone mineral density is reduced, bone microarchitecture is deteriorating, and the amount and variety of proteins in bone is altered...

) may result in fractures.

Occipital horn syndrome
Occipital horn syndrome
Occipital horn syndrome , formerly considered a variant of Ehlers-Danlos syndrome, is an X-linked recessive connective tissue disorder. It is caused by a deficiency in the transport of the essential mineral copper, associated with mutations in the ATP7A gene...

 (sometimes called X-linked cutis laxa or Ehlers-Danlos type 9), is a mild form of Menkes syndrome that begins in early to middle childhood. It is characterized by calcium deposits in a bone at the base of the skull (occipital bone), coarse hair, and loose skin and joints.

Cause and Genetics

Mutation
Mutation
In molecular biology and genetics, mutations are changes in a genomic sequence: the DNA sequence of a cell's genome or the DNA or RNA sequence of a virus. They can be defined as sudden and spontaneous changes in the cell. Mutations are caused by radiation, viruses, transposons and mutagenic...

s in the ATP7A
ATP7A
Copper-transporting ATPase 1 also known as copper pump 1 or Menkes disease-associated protein is a protein that in humans is encoded by the ATP7A gene.- Gene :...

gene
Gene
A gene is a molecular unit of heredity of a living organism. It is a name given to some stretches of DNA and RNA that code for a type of protein or for an RNA chain that has a function in the organism. Living beings depend on genes, as they specify all proteins and functional RNA chains...

, located on chromosome
Chromosome
A chromosome is an organized structure of DNA and protein found in cells. It is a single piece of coiled DNA containing many genes, regulatory elements and other nucleotide sequences. Chromosomes also contain DNA-bound proteins, which serve to package the DNA and control its functions.Chromosomes...

 Xq12-q13, are the cause of Menkes syndrome. This condition is inherited in an X-linked recessive
X-linked recessive
X-linked recessive inheritance is a mode of inheritance in which a mutation in a gene on the X chromosome causes the phenotype to be expressed in males and in females who are homozygous for the gene mutation X-linked recessive inheritance is a mode of inheritance in which a mutation in a gene on...

 pattern. As the result of a mutation in the ATP7A gene, copper is poorly distributed to cells in the body. Copper accumulates in some tissues, such as the small intestine
Small intestine
The small intestine is the part of the gastrointestinal tract following the stomach and followed by the large intestine, and is where much of the digestion and absorption of food takes place. In invertebrates such as worms, the terms "gastrointestinal tract" and "large intestine" are often used to...

 and kidney
Kidney
The kidneys, organs with several functions, serve essential regulatory roles in most animals, including vertebrates and some invertebrates. They are essential in the urinary system and also serve homeostatic functions such as the regulation of electrolytes, maintenance of acid–base balance, and...

s, while the brain and other tissues have unusually low levels. The decreased supply of copper can reduce the activity of numerous copper-containing enzyme
Enzyme
Enzymes are proteins that catalyze chemical reactions. In enzymatic reactions, the molecules at the beginning of the process, called substrates, are converted into different molecules, called products. Almost all chemical reactions in a biological cell need enzymes in order to occur at rates...

s that are necessary for the structure and function of bone
Bone
Bones are rigid organs that constitute part of the endoskeleton of vertebrates. They support, and protect the various organs of the body, produce red and white blood cells and store minerals. Bone tissue is a type of dense connective tissue...

, skin
Skin
-Dermis:The dermis is the layer of skin beneath the epidermis that consists of connective tissue and cushions the body from stress and strain. The dermis is tightly connected to the epidermis by a basement membrane. It also harbors many Mechanoreceptors that provide the sense of touch and heat...

, hair
Hair
Hair is a filamentous biomaterial, that grows from follicles found in the dermis. Found exclusively in mammals, hair is one of the defining characteristics of the mammalian class....

, blood vessel
Blood vessel
The blood vessels are the part of the circulatory system that transports blood throughout the body. There are three major types of blood vessels: the arteries, which carry the blood away from the heart; the capillaries, which enable the actual exchange of water and chemicals between the blood and...

s and the nervous system
Nervous system
The nervous system is an organ system containing a network of specialized cells called neurons that coordinate the actions of an animal and transmit signals between different parts of its body. In most animals the nervous system consists of two parts, central and peripheral. The central nervous...

 such as lysyl oxidase.

Diagnosis and Treatment

Urine homovanillic acid
Homovanillic acid
Homovanillic acid is a major catecholamine metabolite...

/vanillylmandelic acid ratio has been proposed as a screening tool to support earlier detection. Early treatment with subcutaneous (under the skin) or intravenous (in a vein) injections of copper supplements (in the form of acetate salts) may be of some benefit. Other treatment is symptomatic and supportive.

Epidemiology

One European study reported a rate of 1 in 254,000; a Japanese study reported a rate of 1 in 357,143.

External links

The source of this article is wikipedia, the free encyclopedia.  The text of this article is licensed under the GFDL.
 
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