Neuroacanthocytosis | |
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Specialty | Neurology, medical genetics ![]() |
Neuroacanthocytosis is a label applied to several genetic neurological conditions in which the blood contains misshapen, spiculated red blood cells called acanthocytes.
The 'core' neuroacanthocytosis syndromes, in which acanthocytes are a typical feature, are chorea acanthocytosis and McLeod syndrome. Acanthocytes are seen less frequently in other conditions including Huntington's disease-like syndrome 2 (HDL2) and pantothenate kinase-associated neurodegeneration (PKAN).
The neuroacanthocytosis syndromes are caused by a range of genetic mutations and produce a variety of clinical features but primarily produce neurodegeneration of the brain, specifically the basal ganglia.
The diseases are hereditary but rare.
The hallmark of the neuroacanthocytosis syndromes is the presence of acanthocytes in peripheral blood. Acanthocytosis originated from the Greek word acantha, meaning thorn. Acanthocytes are spiculated red blood cells and can be caused by altered distribution of membrane lipids or membrane protein/skeleton abnormalities. In neuroacanthocytosis, acanthocytes are caused by protein but not lipid membrane abnormalities [1]
The 'core' neuroacanthocytosis syndromes are chorea acanthocytosis and McLeod syndrome. Acanthocytes are nearly always present in these conditions and they share common clinical features. Some of these features are also seen in the other neurological syndromes associated with neuroacanthocytosis. [2]
A common feature of the core syndromes is chorea: involuntary dance-like movements. In neuroacanthocytosis, this is particularly prominent in the face and mouth which can cause difficulties with speech and eating. These movements are usually abrupt and irregular and present during both rest and sleep. [3]
Individuals with neuroacanthocytosis also often have parkinsonism, the uncontrolled slowness of movements, and dystonia, abnormal body postures. Many affected individuals also have cognitive (intellectual) impairment and psychiatric symptoms such as anxiety, paranoia, depression, obsessive behavior, and pronounced emotional instability. [4] Seizures may also be a symptom of neuroacanthocytosis. [5]
Onset differs between individual neuroacanthocytosis syndromes but is usually between ages 20 and 40. [6] Affected individuals usually live for 10–20 years after onset. [7]
Core neuroacanthocytosis syndromes | ||||||||||
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Disease | Mutation | Inheritance | ||||||||
Chorea acanthocytosis | VPS13A (CHAC gene) | autosomal recessive | ||||||||
McLeod syndrome | XK gene on X-chromosome | X-linked recessive |
Chorea acanthocytosis is an autosomal recessive disorder caused by mutations in the VPS13A , also called CHAC, on chromosome 9q21. The gene encodes the protein Vacuolar protein sorting-associated protein 13A, also known as chorein. The protein's function is unknown. [8] [9]
Chorea acanthocytosis is characterised by dystonia, chorea and progressive cognitive, behavioural changes and seizures. Strikingly, many people with chorea acanthocytosis uncontrollably bite their tongue, lips, and the inside of the mouth. Eye movement abnormalities are also seen. [9]
There are about 500–1,000 cases of chorea acanthocytosis worldwide and it is not specific to any particular ethnic group. [9]
McLeod syndrome is an X-linked recessive disorder caused by mutations in the XK gene encoding the Kx blood type antigen, one of the Kell antigens. [10]
Like the other neuroacanthocytosis syndromes, McLeod syndrome causes movement disorder, cognitive impairment and psychiatric symptoms. The particular features of McLeod syndrome are heart problems such as arrhythmia and dilated cardiomyopathy (enlarged heart). [10]
McLeod syndrome is very rare. There are approximately 150 cases of McLeod syndrome worldwide. Because of its X-linked mode of inheritance, it is much more prevalent in males. [10]
Many other neurological conditions are associated with acanthocytosis but are not considered 'core' acanthocytosis syndromes. The commonest are:
Currently, no treatment slows the neurodegeneration in any of the neuroacanthocytosis disorders. Medication may be administered to decrease the involuntary movements produced by these syndromes. Antipsychotics are used to block dopamine, anticonvulsants treat seizures and botulinum toxin injections may control dystonia. Patients usually receive speech, occupational and physical therapies to help with the complications associated with movement. Sometimes, physicians will prescribe antidepressants for the psychological problems that accompany neuroacanthocytosis. [5] Some success has been reported with deep brain stimulation. [11] [12]
Mouthguards and other physical protective devices may be useful in preventing damage to the lips and tongue due to the orofacial chorea and dystonia typical of chorea acanthocytosis. [2]
Neuroacanthocytosis was first identified in 1950 as Bassen-Kornzweig disease, or Bassen-Kornzweig Syndrome, a rare, autosomal recessive, childhood-onset disorder in which the body fails to produce chylomicrons, low density lipoprotein (LDL) and very low density lipoprotein (VLDL). Symptoms include ataxia, peripheral neuropathy, retinitis pigmentosa and other forms of nerve dysfunction. It was first noted by the North American physician Frank Bassen, who later partnered with the ophthalmologist Abraham Kornzweig to identify and describe causes and symptoms of the disease. Affected children appear normal at birth but usually fail to thrive during their first year. [13] [14]
A second form of neuroacanthocytosis, Levine-Critchley syndrome, was discovered by the American internist Irvine M. Levine in 1960 and reported in Neurology in 1964, and again in 1968. [15] Subsequently, similar symptoms were identified and described by the British neurologist MacDonald Critchley in 1968. [16] In both cases, the physicians described a hereditary syndrome that combined acanthocytosis with neurological peculiarities but normal serum lipoprotein. Specific symptoms included tics, grimacing, movement disorders, difficulty swallowing, poor coordination, hyporeflexia, chorea, and seizures. Patients often mutilated their tongues, lips, and cheeks. The diseases appeared in both sexes, and were usually diagnosed in infancy. [17]
Research is underway worldwide to increase scientific understanding of these disorders as well to identify prevention and treatment methods. Known genetic mutations provide a basis for studying some of the conditions. [5]
Parkinsonism is a clinical syndrome characterized by tremor, bradykinesia, rigidity, and postural instability. Both hypokinetic as well as hyperkinetic features are displayed by Parkinsonism.These are the four motor symptoms found in Parkinson's disease (PD) – after which it is named – dementia with Lewy bodies (DLB), Parkinson's disease dementia (PDD), and many other conditions. This set of symptoms occurs in a wide range of conditions and may have many causes, including neurodegenerative conditions, drugs, toxins, metabolic diseases, and neurological conditions other than PD.
Abetalipoproteinemia is a disorder characterized by abnormal absorption of fat and fat-soluble vitamins from food. It is caused by a mutation in microsomal triglyceride transfer protein resulting in deficiencies in the apolipoproteins B-48 and B-100, which are used in the synthesis and exportation of chylomicrons and VLDL respectively. It is not to be confused with familial dysbetalipoproteinemia.
Chorea-acanthocytosis is a rare hereditary disease caused by a mutation in a gene that directs structural proteins in red blood cells. It belongs to a group of four diseases characterized under the name neuroacanthocytosis. When a patient's blood is viewed under a microscope, some of the red blood cells appear thorny. These thorny cells are called acanthocytes.
Acanthocyte, in biology and medicine, refers to an abnormal form of red blood cell that has a spiked cell membrane, due to thorny projections. A similar term is spur cells. Often they may be confused with echinocytes or schistocytes.
Pantothenate kinase-associated neurodegeneration (PKAN), formerly called Hallervorden–Spatz syndrome, is a genetic degenerative disease of the brain that can lead to parkinsonism, dystonia, dementia, and ultimately death. Neurodegeneration in PKAN is accompanied by an excess of iron that progressively builds up in the brain.
Aceruloplasminemia is a rare autosomal recessive disorder in which the liver can not synthesize the protein ceruloplasmin properly, which is needed to transport copper around the blood. Copper deficiency in the brain results in neurological problems that generally appear in adulthood and worsen over time. .
XK is a protein found on human red blood cells and other tissues which is responsible for the Kx antigen which helps determine a person's blood type.
McLeod syndrome is an X-linked recessive genetic disorder that may affect the blood, brain, peripheral nerves, muscle, and heart. It is caused by a variety of recessively inherited mutations in the XK gene on the X chromosome. The gene is responsible for producing the Kx protein, a secondary supportive protein for the Kell antigen on the red blood cell surface.
Tourettism refers to the presence of Tourette-like symptoms in the absence of Tourette syndrome, as the result of other diseases or conditions, known as "secondary causes".
VPS13A is a protein that in humans is encoded by the VPS13A gene.
Dopamine-responsive dystonia (DRD) also known as Segawa syndrome (SS), is a genetic movement disorder which usually manifests itself during early childhood at around ages 5–8 years.
Basal ganglia disease is a group of physical problems that occur when the group of nuclei in the brain known as the basal ganglia fail to properly suppress unwanted movements or to properly prime upper motor neuron circuits to initiate motor function. Research indicates that increased output of the basal ganglia inhibits thalamocortical projection neurons. Proper activation or deactivation of these neurons is an integral component for proper movement. If something causes too much basal ganglia output, then the ventral anterior (VA) and ventral lateral (VL) thalamocortical projection neurons become too inhibited, and one cannot initiate voluntary movement. These disorders are known as hypokinetic disorders. However, a disorder leading to abnormally low output of the basal ganglia leads to reduced inhibition, and thus excitation, of the thalamocortical projection neurons which synapse onto the cortex. This situation leads to an inability to suppress unwanted movements. These disorders are known as hyperkinetic disorders.
Neuroferritinopathy is a genetic neurodegenerative disorder characterized by the accumulation of iron in the basal ganglia, cerebellum, and motor cortex of the human brain. Symptoms, which are extrapyramidal in nature, progress slowly and generally do not become apparent until adulthood. These symptoms include chorea, dystonia, and cognitive deficits which worsen with age.
Abraham Leon Kornzweig,, born in New York, was a physician and ophthalmologist specializing in geriatric ophthalmology. He opened a new field in investigative medicine and founded the Society of Geriatric Ophthalmology. He was also widely known as the co-discoverer and namer of Bassen-Kornzweig Syndrome, also called Abetalipoproteinemia. It was first noted by the United States physician Frank Bassen, who partnered Kornzweig to identify and describe causes and symptoms of the disease.
Kufor–Rakeb syndrome (KRS) is an autosomal recessive disorder of juvenile onset also known as Parkinson disease-9 (PARK9). It is named after Kufr Rakeb in Irbid, Jordan. Kufor–Rakeb syndrome was first identified in this region in Jordan with a Jordanian couple's 5 children who had rigidity, mask-like face, and bradykinesia. The disease was first described in 1994 by Najim Al-Din et al. The OMIM number is 606693.
Huntington's disease-like syndromes are a family of inherited neurodegenerative diseases that closely resemble Huntington's disease (HD) in that they typically produce a combination of chorea, cognitive decline or dementia and behavioural or psychiatric problems.
Benign hereditary chorea (BHC), also known as benign familial chorea, is a rare autosomal dominant neurogenetic syndrome. It typically presents itself in childhood with isolated chorea, with average to below average intelligence. Unlike other neurogenetic causes of chorea such as Huntington's disease, BHC is not progressive, and not associated with cognitive decline or psychiatric problems in the vast majority of cases.
Dopamine transporter deficiency syndrome (DTDS), also known as infantile parkinsonism-dystonia, is a rare movement disorder that causes progressively worsening dystonia and parkinsonism. It is the first known inherited dopamine 'transportophathy.'
Mitochondrial membrane protein-associated neurodegeneration (MPAN) is a genetic neurodegenerative disease that causes dystonia, parkinsonism, and iron accumulation in the brain. It is caused by mutations to the gene C19orf12, which has unknown function. This was originally discovered as an autosomal recessive disorder, caused by individuals having two mutations to the gene C19orf12, but autosomal dominant disease caused by a single mutation in the same gene has also been rarely described. Due to the common features of neurodegeneration, brain iron accumulation, and movement disorder it is classified as a neurodegeneration with brain iron accumulation (NBIA) disorder and another name for the condition is neurodegeneration with brain iron accumulation 4 (NBIA4).
SLC13A5 citrate transporter disorder, or SLC13A5 Epilepsy, is a rare genetic spectrum disorder that presents with neurological symptoms. Symptoms include severe seizures, ataxia, dystonia, teeth hypoplasia, poor communication skills, difficulty standing or walking, as well as developmental delay. Other names associated with SLC13A5 Epilepsy include SLC13A5 Citrate Transporter Disorder, Citrate Transporter Disorder, SLC13A5 Deficiency, Early Infantile Epilepsy Encephalopathy 25 (EIEE25), Developmental Epilepsy Encephalopathy 25 (DEE25), and Kohlschutter-Tonz Syndrome (non-ROGDI).
Chromosome+disorders at the U.S. National Library of Medicine Medical Subject Headings (MeSH)