eMedicine Specialties > Neurology > Movement and Neurodegenerative Diseases

Neuroacanthocytosis

Author: Eric Dinnerstein, MD, Consulting Staff Neurologist, Maine Neurology
Coauthor(s): Stephen A Berman, MD, PhD, Professor, Department of Internal Medicine, Section of Neurology, Dartmouth Medical School; Chief, Neurology Service, White River Junction Veterans Medical Center; Maritza Arroyo-Muñiz, MD, Associate Program Director, Professor of Neurology, Department of Neurology, University of Puerto Rico
Contributor Information and Disclosures

Updated: Sep 14, 2006

Introduction

Background

Neuroacanthocytosis is a group of phenotypically and genetically heterogenous neurologic disorders characterized by 2 types of problems, neurologic problems and acanthocytosis. Neurologic problems usually consist of either movement disorders or ataxia, personality changes, cognitive deterioration, axonal neuropathy, and seizures. At some point during the course of the disease, most patients manifest acanthocytosis on the peripheral blood smear, ie, a certain percentage of the patients' erythrocytes (typically 10-30%) have an unusual starlike appearance with spiky- or thorny-appearing projections.

There has been, and there continues to be, considerable disagreement about which specific diseases should be included under the general term neuroacanthocytosis. This is the understandable result of gradually accumulating knowledge of the molecular biological bases of these disorders.

The first form of neuroacanthocytosis to be well described in the medical literature is Bassen-Kornzweig disease, or abetalipoproteinemia (1950), which is an autosomal recessive abnormality of lipoprotein metabolism resulting in ataxia combined with acanthocytosis. In the early descriptions, Bassen-Kornzweig disease was compared with a better known condition, Friedreich ataxia. The two are rather similar except that patients with Bassen-Kornzweig disease have acanthocytosis. In fact, the term acanthocyte was originated by the authors of the seminal Bassen-Kornsweig paper.

The second type of neuroacanthocytosis was described in 1960 by Levine and later in 1968 by Critchley. Just as Bassen-Kornsweig disease looks much like Friedreich ataxia, the Levine-Critchley syndrome, as it came to be called, resembles Huntington disease (HD) with prominent choreiform or choreoathetoid movements, progressive dementia, and, in the original descriptions, autosomal dominant inheritance. One notable difference from HD is that Levine-Critchley syndrome manifests acanthocytosis. When it was originally described, it was also frequently compared with Bassen-Kornzweig disease in that both combined neurologic abnormalities with acanthocytosis but the Levine-Critchley syndrome had normal lipoproteins as well as a later age of onset. What today is recognized as the Levine-Critchley syndrome is caused by a mutation in a specific gene called chorein (also called VPS13A). Interestingly, it is not clear that the original cases reported by Levine and Critchley had that mutation.

Most genetic diseases for the term neuroacanthocytosis is appropriate exhibit phenotypes similar to either Bassen-Kornsweig disease or Levine-Critchley syndrome:

• Similar to Bassen-Kornsweig disease, ie, a hereditary lipoprotein disorder that causes a predominantly sensory ataxia involving the dorsal root ganglia and the ensuing spinocerebellar pathways and projections combined with acanthocytosis:
  • Bassen-Kornsweig disease (abetalipoproteinemia)
  • Familial hypobetalipoproteinemia
  • Other lipoprotein disorders of uncertain significance
• Similar to Levine-Critchley syndrome, ie, a movement disorder with choreiform or Parkinsonlike features combined with dementia, various other neurologic abnormalities, and acanthocytosis:
  • Chorea-acanthocytosis (ChAc) McLeod syndrome (MLS)
  • McLeod syndrome (MLS)
  • Huntington disease–like2 (HDL2)
  • Pantothenate kinase–associated neurodegeneration (PKAN)
  • A number of individual cases and families have been reported that do not seem to fit the existing genetic patterns and which may represent new genetic syndromes yet to be elucidated or perhaps sporadic diseases.

Finally, a number of systemic diseases (usually sporadic) exist in which the combination of neurologic findings and acanthocytosis may actually be incidental. Examples of this type of neuroacanthocytosis include case reports of patients with hepatic encephalopathy, myxedema, or certain types of vasculitis who at some point in their disease show choreiform features plus acanthocytosis. It is not known why such diseases show these features as an occasional manifestation and, in the authors' opinion, it is not correct to call these diseases forms of neuroacanthocytosis per se. However, for the sake of completeness, diseases that have been known to occasionally exhibit features of neuroacanthocytosis will be listed.

Pathophysiology

Multisystem pathology is evident, including severe atrophy of the caudate and putamen with loss of small and medium-sized neurons and an associated astrocytic reaction. Less severe changes are seen in the pallidum.

Neuronal loss and mild gliosis can be seen in the thalamus, substantia nigra, and anterior horn of the spinal cord.

Acanthocytes are seen in peripheral blood smears. Creatine phosphokinase (CPK) level, and occasionally serum transaminases level, are elevated.

Serum vitamin E and lipoprotein levels typically are normal in the neuroacanthocytoses that do not involve abetalipoproteinemia or hypobetalipoproteinemia.

In the few cases for which neurochemical data are available, dopamine was decreased in almost the entire brain, norepinephrine levels were elevated in the putamen and globus pallidus, substance P levels were decreased in the striatum and substantia nigra, and serotonin levels were decreased in the caudate nucleus and substantia nigra. These findings are difficult to interpret because of severe caudate atrophy, concurrent medications, and small sample sizes.

Frequency

United States

Neuroacanthocytosis is a rare disease for which insufficient epidemiological data are available to draw conclusions about frequency.

Mortality/Morbidity

Reported causes of death include the following:

• Emaciation due to progressive weakness and dysphagia
• Tracheobronchial aspiration
• Suicide

Race

This disease has been reported in several races, but epidemiological data are insufficient to report prevalences.

Sex

Data are insufficient, but the condition may be more common in males than in females.

Age

Mean age of onset is 32 years (range, 8-62 y).

Clinical

History

• Involuntary movements
  • Chorea and dystonia, features of hyperkinetic movement disorders, are more frequent than tics and parkinsonism. Several of these disorders may be present simultaneously.
  • Parkinsonism eventually may replace the hyperkinetic state.
  • Orolingual dystonia causes eating problems, dysarthria, and dysphagia (ie, the tongue involuntarily pushes food out of the mouth).
• Personality changes occur, including impulsivity, distractibility, anxiety, depression, apathy, loss of introspection, and compulsivity.
• A peculiar gait is characterized by lurching with long strides and quick, involuntary knee flexion.
• Seizures, generally tonic-clonic (ie, grand mal), occur in 30-40% of patients; they are infrequent and relatively easy to treat.

Physical

• The following signs are observed, in order of frequency: chorea, dystonia (including eating dystonia), other orolinguofacial dyskinesias (with lip biting and dysarthria), vocal and/or motor tics, and parkinsonism.
• Subcortical dementia with executive skill problems of the frontal lobe has been reported.
  • Executive skill problems include perseverative errors, excessive vulnerability to external intrusion, and inability to inhibit immediate and inappropriate responses to stimuli.
  • Visuopraxic disorders, anomia, and verbal as well as nonverbal memory retrieval problems may be noted.
• Axonal neuropathy may present with the following signs:
  • Decreased or absent deep tendon reflexes
  • Muscle wasting (amyotrophy)

Causes

Each major type of neuroacanthocytosis appears to have its own basic etiology, ie, the specific gene in which a mutation is present. The known mutant genes are listed with their respective diseases below.

• The hereditary lipoprotein (typically betalipoprotein) disorders
  • Bassen-Kornsweig disease (abetalipoproteinemia) - Microsomal triglyceride transfer protein (MTP)
  • Familial hypobetalipoproteinemia (FHBL)
    • FHBL1 - Apolipoprotein B (APOB)
    • FHBL2 - Gene not known
  • Other lipoprotein disorders of unknown etiology
• Hereditary movement disorders (choreiform or Parkinsonlike)
  • Chorea-acanthocytosis (ChAc) - Chorein (VPS13A)
  • McLeod syndrome (MLS) - Kell blood group protein
  • Huntington disease–like2 (HDL2) - Junctophilin-3 (JPH3)
  • Pantothenate kinase–associated neurodegeneration (PKAN) - Pantothenatekinase 2 (PANK2)
  • Other genetic and sporadic disorders - Genes not yet elucidated, or multigenetic, or due to sporadic conditions
• Although the ultimate basic etiology of the genetic conditions that cause most of the cases of acanthocytosis is known, it is generally not known how the gene defect produces the pathophysiological abnormalities.
• The etiology is best understood for the betalipoprotein deficiencies. Lack of microsomal triglyceride transfer protein (MTP) or a direct mutation in the gene for betapolipoprotein leads to a decreased absorption of vitamin E as well as other vitamins and possibly other cofactors. This leads to damage to the dorsal root ganglia, spinocerebellar tracts, retina, and cerebellum. It also leads to a defect in the conformation and/or fluidity of the erythrocyte membrane. Band three of the membrane appears to be one of the components significantly involved.
• For the other genetic disorders, the connections between the gene defects and the pathophysiological changes are not known. Again, changes in erythrocyte membrane conformation and/or fluidity (possibly via band three) may be involved in the changes underlying the acanthocytosis.
• In order to better understand the many different types of neuroacanthocytosis, the most common varieties have been organized into a table. The first column lists the Online Mendelian Inheritance in Man number (OMIM#). The Mendelian Inheritance in Man (MIM) catalog (not online) was developed by Dr. Victor McKusick and colleagues at Johns Hopkins University, and the OMIM is hosted by the US National Center for Biotechnology Information on what is essentially the same Web site as PubMed. Also provided in the table are the name, mode of inheritance, locus (including the chromosomal region and the names of the gene and protein if available), onset age, description of the condition, and the pathology. Table 1. Most Common Neuroacanthocytosis Syndromes

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  Table

  OMIM#	Name	Mode	Locus	Onset age	Description	Pathology
  #200150	ChAc or Levine-Critchley syndrome	Autosomal recessive	VPS13A (chorein); 9q21	Adult onset; early to middle age (20-50 y)	Features include choreoathetosis, dystonia, parkinsonism, orofacial dyskinesias, seizures, and neuropathy. Interestingly, whether the original the index cases (ie, Levine, 1960 and 1968; Critchley, 1967 and 1970) were part of the Levine-Critchley syndrome as understood genetically today remains unknown.	Atrophy of the caudate, putamen, globus pallidus, and substantia nigra
  +314850	MLS	X-linked	Kell blood group protein; Xp21	Adult onset middle to late age (40-70 y)	Features include choreoathetosis, dystonia, parkinsonism, seizures, neuropathy, myopathy, and cardiomyopathy	Atrophy of the caudate, putamen, and globus pallidus; substantia nigra not involved
  #606438	HDL2	Autosomal dominant	JPH3; 16q24.3	Onset earlier as repeat size increases (usually 30-40 y)	Features include choreoathetosis, dystonia, parkinsonism, hyperreflexia, dementia, weight loss.	Atrophy of the caudate and putamen
  #234200	PKAN or PANK2 deficiency (previously termed Hallervordan-Spatz disease)	Autosomal recessive	PANK2; 20p13	Childhood onset (by 4-6 y); adult-onset subtypes exist	Features include choreoathetosis, dystonia, dysarthria, rigidity, spasticity, and dementia. PKAN also includes the HARP (hypoprebetalipoproteinemia, acanthocytosis, retinitis pigmentosa, and pallidal degeneration) subtype.	Iron deposition in the globus pallidus (causes "eye-of-the-tiger" sign on MRIs
  #200100	Abeta-lipoproteinemia	Autosomal recessive	MTP; 4q22- q24	Infancy/childhood	Features include ataxia (sensory ataxia with some cerebellar features), visual loss, mental retardation/dementia, low vitamin E level, high cholesterol level, and abnormal lipoprotein electrophoresis.	Dorsal root ganglia, ascending sensory tracts, cuneate and gracile nuclei of cord, spinocerebellar projections; possibly some direct cerebellar involvement; retinitis pigmentosa
  +107730	FHBL1	Autosomal recessive	APOB; 2p24	Infancy/childhood	Features include ataxia (sensory ataxia with some cerebellar features), visual loss, and mental retardation/dementia.	Dorsal root ganglia, ascending sensory tracts, cuneate and gracile nuclei of cord, spinocerebellar projections; possibly some direct cerebellar involvement; retinitis pigmentosa.
  %605019	FHBL2	Possibly autosomal recessive	Unknown (possibly other types as well); 3p22-p21.2	Infancy/childhood	Features are same as for FHBL1.	Same as FHBL1

  OMIM#	Name	Mode	Locus	Onset age	Description	Pathology
  #200150	ChAc or Levine-Critchley syndrome	Autosomal recessive	VPS13A (chorein); 9q21	Adult onset; early to middle age (20-50 y)	Features include choreoathetosis, dystonia, parkinsonism, orofacial dyskinesias, seizures, and neuropathy. Interestingly, whether the original the index cases (ie, Levine, 1960 and 1968; Critchley, 1967 and 1970) were part of the Levine-Critchley syndrome as understood genetically today remains unknown.	Atrophy of the caudate, putamen, globus pallidus, and substantia nigra
  +314850	MLS	X-linked	Kell blood group protein; Xp21	Adult onset middle to late age (40-70 y)	Features include choreoathetosis, dystonia, parkinsonism, seizures, neuropathy, myopathy, and cardiomyopathy	Atrophy of the caudate, putamen, and globus pallidus; substantia nigra not involved
  #606438	HDL2	Autosomal dominant	JPH3; 16q24.3	Onset earlier as repeat size increases (usually 30-40 y)	Features include choreoathetosis, dystonia, parkinsonism, hyperreflexia, dementia, weight loss.	Atrophy of the caudate and putamen
  #234200	PKAN or PANK2 deficiency (previously termed Hallervordan-Spatz disease)	Autosomal recessive	PANK2; 20p13	Childhood onset (by 4-6 y); adult-onset subtypes exist	Features include choreoathetosis, dystonia, dysarthria, rigidity, spasticity, and dementia. PKAN also includes the HARP (hypoprebetalipoproteinemia, acanthocytosis, retinitis pigmentosa, and pallidal degeneration) subtype.	Iron deposition in the globus pallidus (causes "eye-of-the-tiger" sign on MRIs
  #200100	Abeta-lipoproteinemia	Autosomal recessive	MTP; 4q22- q24	Infancy/childhood	Features include ataxia (sensory ataxia with some cerebellar features), visual loss, mental retardation/dementia, low vitamin E level, high cholesterol level, and abnormal lipoprotein electrophoresis.	Dorsal root ganglia, ascending sensory tracts, cuneate and gracile nuclei of cord, spinocerebellar projections; possibly some direct cerebellar involvement; retinitis pigmentosa
  +107730	FHBL1	Autosomal recessive	APOB; 2p24	Infancy/childhood	Features include ataxia (sensory ataxia with some cerebellar features), visual loss, and mental retardation/dementia.	Dorsal root ganglia, ascending sensory tracts, cuneate and gracile nuclei of cord, spinocerebellar projections; possibly some direct cerebellar involvement; retinitis pigmentosa.
  %605019	FHBL2	Possibly autosomal recessive	Unknown (possibly other types as well); 3p22-p21.2	Infancy/childhood	Features are same as for FHBL1.	Same as FHBL1

• The diseases in the next table are even rarer than those listed in the previous table. In some of these, the neuroacanthocytosis appears to represent an exception and possibly idiosyncratic reaction seen in some patients with concomitant diseases; however, the full range of acanthocytosis is not yet completely understood. What in current practice may appear to be an isolated idiosyncratic case may, in the future, stand as a part of a broader syndrome. Table 2. Extremely Rare or Uncertain Causes of Neuroacanthocytosis

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  Table

  OMIM	Name	Mode	Locus	Discription
  #540000	Mitochondrial encephalopathy, lactic acidosis, and stroke (MELAS) with acanthocytosis	Mitochondrial for MELAS but this case is not proven	Mitochondrial genome for MELAS but this case is not proven	This is a single case. Typically, MELAS is an A3243G mutation. (Adenine is replaced by guanosine at position 3243 in the mitochondrial genome.) This single case report did not have mitochondrial genomic sequencing. Pathology reports showed abnormalities in Betz cells, brainstem neurons, and anterior horn cells. Muscle pathology results are compatible with MELAS.
  N/A	Familial acanthocytosis with paroxysmal exertion-induced dyskinesias and epilepsy (FAPED)	Autosomal dominant (not certain; only one family)		This is characterized by intermittent attacks of cramps and involuntary movements; attacks are myoclonic and atonic epilepsy. It has been described in one family. MRI showed mild basal ganglia degeneration. Positron emission tomography scanning showed decreased glucose metabolism in the thalamus.
  #607689	Anderson disease	Autosomal recessive for Anderson disease; very rarely has features of neuroacanthocytosis; (possible coincidental association with Anderson disease or misdiagnosis)	Unknown (not the gene for ApoB), 5q31.1	Patients usually have severe intestinal fat malabsorption with diarrhea, steatorrhea, hypobetalipoproteinemia, low cholesterol levels, low triglyceride levels, low phospholipid levels, and failure to secrete chylomicrons after a fatty meal. Typically, acanthocytes, retinitis pigmentosa, and ataxia are lacking, but rare cases may be associated with acanthocytes and some neurological problems and so may be considered a neuroacanthocytosis in those instances.
  +278000 or 278100	Atypical Wolman disease	Unknown (single case)	Unknown (single case)	In 1970, Eto and Kitagawa described a patient with lipid malabsorption, vomiting, growth failure, adrenal calcification, hypolipoproteinemia, and acanthocytosis and termed it Wolman disease (OMIM #278000). The patient had hepatosplenomegaly, steatorrhea, abdominal distention, and adrenal calcification that appeared in the first weeks of life, as well as widespread accumulation of cholesterol esters and triglycerides in the internal organs. Typically, Wolman disease is not associated with acanthocytes or neurological problems. This single case has now been given its own number (OMIM #278100). Whether this case is truly Woman disease is uncertain.

  OMIM	Name	Mode	Locus	Discription
  #540000	Mitochondrial encephalopathy, lactic acidosis, and stroke (MELAS) with acanthocytosis	Mitochondrial for MELAS but this case is not proven	Mitochondrial genome for MELAS but this case is not proven	This is a single case. Typically, MELAS is an A3243G mutation. (Adenine is replaced by guanosine at position 3243 in the mitochondrial genome.) This single case report did not have mitochondrial genomic sequencing. Pathology reports showed abnormalities in Betz cells, brainstem neurons, and anterior horn cells. Muscle pathology results are compatible with MELAS.
  N/A	Familial acanthocytosis with paroxysmal exertion-induced dyskinesias and epilepsy (FAPED)	Autosomal dominant (not certain; only one family)		This is characterized by intermittent attacks of cramps and involuntary movements; attacks are myoclonic and atonic epilepsy. It has been described in one family. MRI showed mild basal ganglia degeneration. Positron emission tomography scanning showed decreased glucose metabolism in the thalamus.
  #607689	Anderson disease	Autosomal recessive for Anderson disease; very rarely has features of neuroacanthocytosis; (possible coincidental association with Anderson disease or misdiagnosis)	Unknown (not the gene for ApoB), 5q31.1	Patients usually have severe intestinal fat malabsorption with diarrhea, steatorrhea, hypobetalipoproteinemia, low cholesterol levels, low triglyceride levels, low phospholipid levels, and failure to secrete chylomicrons after a fatty meal. Typically, acanthocytes, retinitis pigmentosa, and ataxia are lacking, but rare cases may be associated with acanthocytes and some neurological problems and so may be considered a neuroacanthocytosis in those instances.
  +278000 or 278100	Atypical Wolman disease	Unknown (single case)	Unknown (single case)	In 1970, Eto and Kitagawa described a patient with lipid malabsorption, vomiting, growth failure, adrenal calcification, hypolipoproteinemia, and acanthocytosis and termed it Wolman disease (OMIM #278000). The patient had hepatosplenomegaly, steatorrhea, abdominal distention, and adrenal calcification that appeared in the first weeks of life, as well as widespread accumulation of cholesterol esters and triglycerides in the internal organs. Typically, Wolman disease is not associated with acanthocytes or neurological problems. This single case has now been given its own number (OMIM #278100). Whether this case is truly Woman disease is uncertain.

• Various systemic diseases may also be accompanied by acanthocytosis and neurological findings, especially in severely ill patients. These include various cancers, thyroid disorders, patients who have had a splenectomy, cirrhosis of the liver and hepatic encephalopathy, psoriasis, and an obscure condition called Eales disease in which an idiopathic inflammatory venous occlusion primarily affects the peripheral retina in adults. In these conditions, the presentation as neuroacanthocytosis may be a coincidence in which some type of neurological insult, such as a stroke due to vasculitis, coincides with bone marrow failure in a severely ill individual; alternatively, a more fundamental connection may be present that is not currently understood.

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