Neuroacanthocytosis McLeod syndrome ... (neuroacanthocytosis McLeod syndrome) - Gen XK
Neuroacanthocytosis syndrome McLeod is a neurological disorder that affects movement in many parts of the body and affects almost exclusively males. This disease is one of a group of disorders called neuroacanthocytosis, involving neurological problems and anomalies in erythrocytes. People with this disease have acanthocytosis.
Signs and symptoms of the disease include myopathy, atrophy, chorea (particularly affecting the arms and legs), peripheral neuropathy, dystonia in the face and throat and seizures. Often people affected as l can develop cognitive impairment, neurogenic atrophy, arrhythmia and dilated cardiomyopathy. Usually t he signs and symptoms of the syndrome begin in mid-adulthood. Behavioral changes, such as lack of self - control, inability to care for oneself, anxiety and personality changes may be early signs of the disease. In addition, these individuals may manifest psychiatric disorders such as depression, bipolar disorder, psychosis or obsessive-compulsive disorder. While these behavioral changes are usually not progressive, movement problems and intellectual disabilities tend to worsen with age.
This process is due to mutations in the XK gene (X-linked blood group Kx), located on the short arm of the X chromosome (Xp21.1). This gene encodes the synthesis of a protein found in various body tissues, particularly the brain, muscles and heart. This protein is also present on the surface of erythrocytes and contains a molecule known as Kx antigen blood group. These antigens are on the surface of erythrocytes and determine a number of blood types. When blood cells with unknown antigens enter the bloodstream, the body 's immune system recognizes as foreign cells and can trigger an immune reaction that destroys them . Although the function of the XK protein is unclear, though it could play a role in the transport of substances inside and outside cells. In erythrocytes, the XK protein binds to another protein blood group, the Kell protein.
They have identified approximately 30 mutations in the gene that cause XK of neuroacanthocytosis McLeod syndrome. Mutations in the gene, leading to synthesis of an abnormally short, nonfunctional, or even total absence protein. The lack of protein causes XK absence of antigens on erythrocytes Kx. Kx antigen deficiency, known as the "phenotype McLeod," refers only to erythrocytes. It is not known how the lack of protein XK leads to problems of movement and other characteristics of neuroacanthocytosis of McLeod syndrome.
This process is inherited in an X - linked recessive pattern, because the gene related to this alteration is on the X chromosome. In males, an altered copy of the gene in each cell is sufficient to express syndrome. In women, a mutation must be present in both copies of the gene to cause the disorder. Males are affected by X - linked recessive disorders much more frequently than women. Rarely, women with a mutation in a copy of XK gene have abnormal blood cells and movement problems associated with the syndrome. A feature of the X - linked inheritance is that fathers can not pass X - linked traits to their children.
Tests in IVAMI: in IVAMI perform detection of mutations associated with syndrome neuroacanthocytosis McLeod, by complete PCR amplification of the exons of the XK gene, and subsequent sequencing.
Samples recommended: EDTA blood collected for separation of blood leukocytes, or impregnated sample card with dried blood (IVAMI may mail the card to deposit the blood sample).