Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:Q00604 (X-linked)
 16,883 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The McLeod syndrome is an X-linked neuroacanthocytosis manifesting with myopathy and progressive chorea. It is caused by mutations of the XK gene encoding the XK protein, a putative membrane transport protein of yet unknown function. In erythroid tissues, XK forms a functional complex with the Kell glycoprotein. Here, we present an immunohistochemical study in skeletal muscle of normal controls and a McLeod patient with a XK gene point mutation (C977T) using affinity-purified antibodies against XK and Kell proteins. Histological examination of the affected muscle revealed the typical pattern of McLeod myopathy including type 2 fiber atrophy. In control muscles, Kell immunohistochemistry stained sarcoplasmic membranes. XK immunohistochemistry resulted in a type 2 fiber-specific intracellular staining that was most probably confined to the sarcoplasmic reticulum. In contrast, there was only a weak background signal without a specific staining pattern for XK and Kell in the McLeod muscle. Our results demonstrate that the lack of physiological XK expression correlates to the type 2 fiber atrophy in McLeod myopathy, and suggest that the XK protein represents a crucial factor for the maintenance of normal muscle structure and function.
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PMID:Kell and XK immunohistochemistry in McLeod myopathy. 1156 15

The term acanthocytosis is derived from the Greek for "thorn" and is used to describe a peculiar spiky appearance of erythrocytes. Acanthocytosis is found to be associated with at least three hereditary neurological disorders that are generally referred to as neuroacanthocytosis. Abetalipoproteinaemia is an autosomal recessive condition, characterised by absence of serum apolipoprotein B containing lipoproteins leading to fat intolerance and fat-soluble vitamin deficiency. This results in a progressive spinocerebellar ataxia with peripheral neuropathy and retinitis pigmentosa. Chorea-acanthocytosis is also an autosomal recessive condition and is characterised by chorea, orofaciolingual dyskinesia, dysphagia, dysarthria, areflexia, seizures and dementia. Some of its features, including choreic movements, peripheral neuropathy with areflexia, elevated serum creatine kinase levels and myopathy are shared by another form of neuroacanthocytosis, McLeod syndrome. Patients affected by this X-linked disorder also show abnormal expression of Kell blood group antigens and a permanent haemolytic state. In addition to these cases, acanthocytosis is occasionally associated with other neurological disorders, such as Hallervorden-Spatz disease. For each of the neuroacanthocytosis syndromes we review the main clinical features and their molecular bases. The recent molecular genetics findings are the first step towards the understanding of the pathogenetic mechanisms and eventually the search for effective treatments.
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PMID:Clinical features and molecular bases of neuroacanthocytosis. 1218 48

Mild myopathy is a common manifestation of the X-linked McLeod neuroacanthocytosis syndrome. We present a patient with McLeod syndrome and a primarily subclinical myopathy, who developed severe rhabdomyolysis with renal insufficiency after a prolonged period of excessive motor restlessness due to an agitated psychotic state and a single dose of clozapine. Other possible causes for rhabdomyolysis such as prolonged immobility, trauma, hyperthermia, generalized seizures, toxin exposure, or metabolic changes were excluded. Clinical course was favorable, with persistent slight elevation of serum creatine kinase levels caused by the underlying myopathy. Our findings suggest that McLeod myopathy is a predisposing factor for severe rhabdomyolysis. This possibly life-threatening condition should be added to the clinical spectrum of McLeod syndrome, and serum creatine kinase levels should be carefully monitored in patients with this syndrome, particularly if a hyperkinetic movement disorder is present or neuroleptic medication is used.
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PMID:Malignant McLeod myopathy. 1221 Mar 75

McLeod syndrome and chorea-acanthocytosis are classified with the so-called neuroacanthocytosis group of syndromes. Both lead to progressive basal ganglia degeneration and were not easily distinguished in the past. With the discovery of their molecular bases, mutations of the X-linked gene XK and autosomal recessive mutations of the gene coding for chorein, respectively, the two phenotypes can now be differentiated and extend the diagnostic spectrum in patients presenting with chorea. The present review compares the two conditions and proposes a practical approach to diagnosis and treatment. Better-defined disease concepts should eventually replace the umbrella term of "neuroacanthocytosis." Animal models are needed to understand the underlying mechanisms. A final common pathway is likely for the pathogenesis of these conditions and is most probably shared with Huntington's disease.
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PMID:[Progress in molecular chorea diagnosis. McLeod syndrome and chorea acanthocytosis]. 1224 6

McLeod Syndrome (MLS) is a rare X-linked disorder characterized by haemopoietic abnormalities and late-onset neurological and muscular defects. The McLeod blood group phenotype is typically associated with erythrocyte acanthocytosis, absence of the Kx antigen and reduced expression of Kell system antigens. MLS is caused by hemizygosity for mutations in the XK gene. We describe a patient with MLS who first showed symptoms in 1989 (aged 51 years). As the disease progressed, the patient developed a slight dementia, aggressive behaviour and choreatic movements. A cardiomyopathy was also diagnosed. An electroneuromyography showed neuropathic and myopathic changes. Liver enzymes were elevated and a blood smear showed acanthocytes. MLS was confirmed by serological analysis of the Kell antigens. Analysis of red blood cells by flow cytometry revealed the patient and his grandson to have reduced Kell antigen expression. The patient's daughters had two populations of red cells, consistent with them being heterozygous for an XK0 allele. The molecular basis of MLS in this family is a novel mutation consisting of a 7453-bp deletion that includes exon 2 of the XK gene. This confirms that the patient's 7-year-old grandson, who is currently asymptomatic, also has the XK0 allele and is therefore likely to develop MLS.
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PMID:McLeod syndrome resulting from a novel XK mutation. 1289 25

It is important to identify the McLeod phenotype in order to differentiate the McLeod syndrome from other causes of acanthocytosis, e.g., chorea acanthocytosis. A proportion of males with the McLeod phenotype have X-linked chronic granulomatous disease. Because anti-Kx + -Km, which is needed for identification, is not readily available, detection of the McLeod phenotype relies on observed weakening of Kell antigens on the individual's red blood cells (RBCs). Identification of McLeod carrier females (obligate heterozygotes) is even more difficult because only a minor subpopulation of RBCs may express the weakened Kell phenotype. RBCs from 12 sets of mother/son or father/daughter pairs were tested by standard hemagglutination tube tests and by flow cytometry using both monoclonal and polyclonal Kell system antibodies. Monoclonal anti-K14 (G10) in tests with RBCs from McLeod males reacted +/- by hemagglutination (control cells 2+) and had a median fluorescence of 6-11 by flow cytometry (control cells 441). Monoclonal anti-k (F7) and human polyclonal anti-k (C30A-1) gave stronger reactions by hemagglutination with RBCs from McLeod males and were not appropriate to differentiate RBCs with the McLeod phenotype from RBCs with normal Kell antigen expression. Crisp mixed-field agglutination was obtained in tests with monoclonal anti-K14 versus RBCs from the 12 obligate carrier females. Flow cytometry using anti-K14 also clearly identified two RBC populations (median fluorescence of 6-11 and 229-382, respectively). Kell system antibodies may vary in their ability to detect a weakened expression of the corresponding antigen on RBCs with the McLeod phenotype by hemagglutination. Antibodies suitable for differentiating McLeod syndrome from other forms of acanthocytosis should be reagents that are preselected after extensive testing. In this study, flow cytometry clearly identified the two RBC populations in McLeod carrier females.
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PMID:A method to detect McLeod phenotype red blood cells. 1538 28

Neurological abnormalities associated with spiculated, "acanthocytic" red cells in blood have been summarized as neuroacanthocytosis. This is a heterogeneous group of conditions that can now be clearly subdivided on the basis of genetic discoveries. The core neuroacanthocytosis syndromes are autosomal recessive chorea-acanthocytosis (ChAc) and the X-linked McLeod syndrome (MLS). Huntington's disease-like 2 (HLD2) and pantothenate kinase associated neurodegeneration (PKAN) can now also be included. All of these share dyskinesias, cognitive deterioration and progressive neurodegeneration mainly of the basal ganglia, but they are sufficiently distinct to permit a specific working diagnosis on the basis of clinical, laboratory and imaging findings. In addition, the VPS13A (formerly called CHAC), XK, JPH3 and PANK2 genes, respectively, may be examined for mutations. Unfortunately, little is yet known about the normal and abnormal physiology of the protein products of these genes, but they appear to be involved in membrane function and intracellular protein sorting. Since no cures are yet available, development and study of disease models in experimental animals (mouse, C. elegans) is a priority for current research. From a clinical point of view, the common occurrence of cardiomyopathy in MLS, the transfusion hazards due to the McLeod Kell phenotype and the possibility of improving the violent trunk spasms and orofacial dyskinesias typical for ChAc (with subsequent lip or tongue mutilations and feeding dystonia) by deep brain surgery or stimulation should be considered in patient management.
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PMID:Neuroacanthocytosis: new developments in a neglected group of dementing disorders. 1576 Jun 37

McLeod syndrome is an X-linked multisystem disorder affecting red blood cells, the peripheral and central nervous systems, and skeletal and cardiac muscle. No clear correlations of the clinical findings with the genotype of XK mutations have yet been uncovered. Here, we report the clinical features and progression in 10 affected brothers from 4 families with McLeod syndrome. There is significant variation in clinical presentation within families, including in causes of morbidity and mortality. This phenotypic variation, despite shared mutations, suggests the action of disease-modifying factors that may explain some of the difficulties with genotype-phenotype correlation in McLeod syndrome.
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PMID:Phenotypic variation among brothers with the McLeod neuroacanthocytosis syndrome. 1713 13

The term "neuroacanthocytosis" is normally used to refer to autosomal recessive chorea-acanthocytosis and X-linked McLeod syndrome, but there are other movement disorders in which erythrocyte acanthocytosis may also be seen, such as Huntington disease-like 2 and pantothenate kinase-associated neurodegeneration. Disorders of serum lipoproteins such as Bassen-Kornzweig disease form a distinct group of neuroacanthocytosis syndromes in which ataxia is observed, but movement disorders are not seen. Genetic testing has enabled us to distinguish between these disorders, even when there are considerable similarities between phenotypes. Improved detection is important for accurate genetic counseling, for monitoring for complications, and, it is hoped, for implementing causal treatments, once these become available. As in other neurodegenerative conditions, animal models are a promising strategy for the development of such therapies.
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PMID:Neurologic phenotypes associated with acanthocytosis. 1721 Aug 89

Neurological abnormalities associated with spiculated, "acanthocytic" red cells in blood have been described as neuroacanthocytosis. This is a heterogeneous group of conditions that can be clearly subdivided on the basis of recent genetic findings. The McLeod Syndrome, one of the core neuroacanthocytosis syndromes, is a rare X-linked disorder caused by mutations of the XK gene, an X-chromosomal gene of unknown function characterized by haemopoietic abnormalities and late-onset neurological and muscular defects. We report two Chilean brothers with the McLeod phenotype who showed important psychiatric features. The diagnosis may be elusive if the presence of acanthocytosis is not properly studied. We describe a method which allowed the diagnosis that unmasked acanthocytosis. Otherwise the condition could have remained undiagnosed as it had been for decades in this family. This syndrome must be considered when assessing a familial movement disorder, specially affecting males with relevant psychiatric features. A reliable test for acanthocytosis assessment is available.
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PMID:[McLeod syndrome: Multisystem involvement associated with neuroacanthocytosis linked to X chromosome. report of two related cases]. 1727 57


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