"Myopathic" changes in chorea-acanthocytosis. Clinical and histopathological studies

Chorea-acanthocytosis

A middle-aged Asian man had gait difficulty progressing over several years. His speech had gradually become slurred with involuntary tongue biting. He was the product of a consanguineous marriage with no other relevant family history. MR scan of brain showed bilateral caudate atrophy. Nerve conduction studies showed a predominantly sensory peripheral neuropathy. Serum creatine kinase was slightly elevated but electromyography showed no evidence of myopathy. Three consecutive peripheral blood films were negative for acanthocytes. Whole-genome sequencing confirmed a mutation in VPS13A gene, consistent with autosomal recessive chorea-acanthocytosis.

Neuroacanthocytosis Syndromes in an Italian Cohort: Clinical Spectrum, High Genetic Variability and Muscle Involvement

Neuroacanthocytosis (NA) syndromes are a group of genetically defined diseases characterized by the association of red blood cell acanthocytosis, progressive degeneration of the basal ganglia and neuromuscular features with characteristic persistent hyperCKemia. The main NA syndromes include autosomal recessive chorea-acanthocytosis (ChAc) and X-linked McLeod syndrome (MLS). A series of Italian patients selected through a multicenter study for these specific neurological phenotypes underwent DNA sequencing of the VPS13A and XK genes to search for causative mutations. Where it has been possible, muscle biopsies were obtained and thoroughly investigated with histochemical assays. A total of nine patients from five different families were diagnosed with ChAC and had mostly biallelic changes in the VPS13A gene (three nonsense, two frameshift, three splicing), while three patients from a single X-linked family were diagnosed with McLeod syndrome and had a deletion in the XK gene. Despite a very low incidence (only one thousand cases of ChAc and a few hundred MLS cases reported worldwide), none of the 8 VPS13A variants identified in our patients is shared by two families, suggesting the high genetic variability of ChAc in the Italian population. In our series, in line with epidemiological data, McLeod syndrome occurs less frequently than ChAc, although it can be easily suspected because of its X-linked mode of inheritance. Finally, histochemical studies strongly suggest that muscle pathology is not simply secondary to the axonal neuropathy, frequently seen in these patients, but primary myopathic alterations can be detected in both NA syndromes.

Deficiency of the E3 ubiquitin ligase TRIM32 in mice leads to a myopathy with a neurogenic component

Limb-girdle muscular dystrophy type 2H (LGMD2H) and sarcotubular myopathy are hereditary skeletal muscle disorders caused by mutations in TRIM32. We previously identified TRIM32 as an E3 ubiquitin ligase that binds to myosin and ubiquitinates actin. To date four TRIM32 mutations have been linked to LGMD2H, all of which occur in the C-terminal NHL domains. Unexpectedly, a fifth mutation in the B-box of TRIM32 causes a completely different, multisystemic disorder, Bardet-Biedl syndrome type 11. It is not understood how allelic mutations in TRIM32 can create such diverse phenotypic outcomes. To generate a tool for elucidating the complex in vivo functions of TRIM32, we created the first murine Trim32 knock-out model (T32KO). Histological analysis of T32KO skeletal muscles revealed mild myopathic changes. Electron microscopy showed areas with Z-line streaming and a dilated sarcotubular system with vacuoles -- the latter being a prominent feature of sarcotubular myopathy. Therefore, our model replicates phenotypes of LGMD2H and sarcotubular myopathy. The level of Trim32 expression in normal mouse brain exceeds that observed in skeletal muscle by more than 100 times, as we demonstrated by real-time PCR. Intriguingly, analysis of T32KO neural tissue revealed a decreased concentration of neurofilaments and a reduction in myelinated motoraxon diameters. The axonal changes suggest a shift toward a slower motor unit type. Not surprisingly, T32KO soleus muscle expressed an elevated type I slow myosin isotype with a concomitant reduction in the type II fast myosin. These data suggest that muscular dystrophy due to TRIM32 mutations involves both neurogenic and myogenic characteristics.

Primary skeletal muscle involvement in chorea-acanthocytosis

Chorea-acanthocytosis (ChAc) is a hereditary disease characterized by involuntary movements and amyotrophy with elevation of serum creatine kinase. Although skeletal muscle involvement in ChAc has been suggested, the mechanism remains unclear. To investigate chorein abnormalities of the skeletal muscles of ChAc patients with an apparently heterozygous VPS13A mutation compared with those of other hereditary choreic diseases, we performed histological and immunohistochemical studies of the skeletal muscles from 3 ChAc, 1 Huntington's disease (HD), 1 McLeod syndrome (MLS), and 1 normal control (NC) with 2 originally generated anti-chorein antibodies. Chorein immunoreactivities in HD, MLS, and NC were found linearly along the sarcolemma and appeared as speckles in the sarcoplasma, but those in ChAc were uneven and discontinuous along the sarcolemmas and increased in the sarcoplasma especially in type I fibers. This histological observation suggests chorein abnormalities of skeletal muscles might be associated with primary involvement of skeletal muscles in this disorder.

Nemaline rods in chorea-acanthocytosis

In chorea-acanthocytosis, a neurological disorder associated with multisystem degeneration, amyotrophy and peripheral neuropathy are sometimes conspicuous. We describe a patient with chorea-acanthocytosis who showed distributed nemaline rods in biopsied muscle. It has been suggested that in chorea-acanthocytosis, the muscle membranous structures are disordered, and our finding may be attributable to this underlying myopathic condition.

Neuroacanthocytosis misdiagnosed as Huntington's disease: a case report

A patient with the typical features of neuroacanthocytosis is reported. Chorea, tics, personality changes and caudate atrophy on cranial MRI resulted in an erroneous diagnosis of Huntington's disease elsewhere. Attention to other features viz., absence of ocular motility disturbances, amyotrophy, areflexia, EMG evidence of axonopathy, raised serum creatinine phosphokinase (CPK) levels and the typical erythrocytic acanthocytosis enabled us to establish the correct diagnosis. The typical features of the disease as seen in the patient are discussed. In view of the implications for genetic counseling, careful clinical and laboratory evaluation is always warranted to exclude neuroacanthocytosis in all suspected cases of Huntington's disease.

The neuropathological features of neuroacanthocytosis

In this article we describe the neuropathological changes in three patients with neuroacanthocytosis and review the neuropathology of the other eight cases reported in the literature. Macroscopically the brains showed enlargement of the lateral ventricles, especially the frontal horns. The most severely and consistently affected brain areas were the caudate nucleus and putamen, which were atrophic and showed by light microscopy marked neuronal loss and gliosis. Small and medium-sized striatal neurons were particularly depleted. The globus pallidus was almost as severely involved as the striatum. In some cases the thalamus, substantia nigra, and anterior horns of the spinal cord showed pathology, mainly neuronal loss and mild gliosis. Brain areas with no pathology included the subthalamic nucleus, cerebral cortex, cerebellum, pons, and medulla. The preservation of these areas may help in the neuropathological distinction of neuroacanthocytosis from Huntington's disease.

Choreo-acanthocytosis like phenotype without acanthocytes: clinicopathological case report. A contribution to the knowledge of the functional pathology of the caudate nucleus

Detailed clinical and neuropathological findings in two unrelated patients with a chorea-acanthocytosis-like phenotype (CA) are reported. One case met all the diagnostic criteria of CA and had a deceased brother with the same disease. The second case had a virtually identical phenotype to the former but without acanthocytes. These findings suggest that both patients are affected by the same disease and that acanthocytes are not essential to the diagnosis. Neuropathological autopsy studies on the brain of the second case showed selective atrophy of the caudate nucleus that seemed to correspond to the movement disorder and behavioural abnormalities prominent in this patient. In both subjects, morphometric and ultrastructural examination of the peripheral nerve showed loss of myelinated fibres, more accentuated distally, and cytoskeletal changes in the axoplasm. These findings support the hypothesis that peripheral neuropathy in CA is caused by distal axonopathy.

Amyotrophic choreo-acanthocytosis: a neuropathological and immunocytochemical study

A 47 year old man, one of a sibship affected by amyotrophic choreo-acanthocytosis was studied neuropathologically after some years of clinical observation. Besides the classic optical findings (neuronal loss, astrocytic gliosis and "status spongiosus" in the basal ganglia, namely in the caudate nucleus) a few MEnk+ and NPY+ neurons were observed immunocytochemically in the striatum. In the spinal cord also, while no neuronal loss was perceivable, both mild demyelination and interfibrillary astrocytic hyperplasia of the long tracts were present. On the other hand, microscopic findings of muscle and peripheral nerve showed no differences from what was previously intra-vitam appreciated in the same patient. The neuropathological and immunocytochemical findings of this case are discussed in relation to the differential diagnosis between amyotrophic choreo-acanthocytosis and Huntington's disease.

Parkinsonism with neuroacanthocytosis

Two patients with neuroacanthocytosis are described. One presented with parkinsonism and the other resembled diurnal dystonia of the Segawa type. Both patients responded well to dopaminomimetic therapy. A PET scan with fluorodopa revealed a nigrostriatal deficit in the first patient.

Chorea-acanthocytosis: report of a family and neuropathological study of two cases

We report three siblings, offspring of normal consanguineous parents, with a progressive neurological illness that began in midlife and was characterized primarily by chorea and leading to death in the fourth decade. The proband had erythrocyte acanthocytosis with normal serum beta-lipoprotein. Biopsy of left gastrocnemius muscle showed neurogenic muscular atrophy. There was a decrease in the numbers of large myelinated axons of the sural nerve. Postmortem examination of two cases showed marked atrophy, neuronal loss and gliosis of the caudate nucleus and putamen. Autosomal recessive inheritance is likely in this family.

Peripheral neuropathy in amyotrophic chorea-acanthocytosis

We investigated involvement of the peripheral nervous system in 6 patients with amyotrophic chorea-acanthocytosis. Electromyographic and neurographic findings, and pathological changes as demonstrated by examination of biopsy specimens of muscle and sural nerve indicate that most patients had an axonal sensorimotor polyneuropathy with more pronounced involvement of the distal portion of the nerves. Results obtained in one patient raised the question of an anterior horn cell disorder.

Neurochemical findings in neuroacanthocytosis

We performed a neurochemical study of the brain of two unrelated patients, living in different continents, with neuroacanthocytosis. The levels of monoamines and their metabolites, gamma-aminobutyric acid and substance P, were measured in several brain areas and the monoamine metabolites in cerebrospinal fluid. The binding of 3H-spiperone to striatal membranes and to lymphocytes was also measured. Both patients had a progressive neurological disorder with onset in the third decade of life and characterized by a complex movement disorder, epilepsy, muscular wasting, and changes in behavior. The movement disorder initially manifested with oromandibular dystonia and limb chorea, but at the time of death was characterized by a severe dystonic syndrome. The chemical changes were similar in the two patients. The most important neurochemical findings were a depletion of dopamine and its metabolites in most brain areas, most notably in the striatum, and elevation of norepinephrine levels in the putamen and globus pallidus. Substance P was markedly reduced in the striatum and substantia nigra. Our findings may provide clues to the neurochemical mechanisms underlying dystonia.

Chorea-acanthocytosis: a report of three new families and implications for genetic counselling

Chorea-acanthocytosis (CHA) is a rare inherited neurologic disorder with peripheral red cell acanthocytes and normal serum lipoprotein levels. To date, 8 families with the disorder have been reported outside of Japan. We describe 4 patients in 3 families with CHA and review the clinical presentations in previous reports. In addition, we report magnetic resonance imaging scans in these patients. The pattern of inheritance in these families is most likely autosomal recessive. Obligate heterozygotes do not have acanthocytes on wet preparation under phase microscope. Two of 3 propositi were initially diagnosed as having Huntington chorea. Chorea-acanthocytosis is an important differential in the diagnosis of Huntington chorea and should be considered in families without a family history. The paucity of families with CHA reported to date may represent lack of recognition.

Peripheral nerve involvement in familial chorea-acanthocytosis

Myelinated fibers and neuronal cell bodies of the ventral spinal outflow and primary sensory neurons were histopathologically examined in a patient with familial chorea-acanthocytosis and age-matched controls. The patient exhibited a marked loss of large myelinated axons and their neuronal cell bodies in the ventral spinal outflow, while there was frequent occurrence of axonal sprouts. Large myelinated fibers in sensory afferents were also decreased in number. Segmental de- and remyelination was markedly increased in teased fiber preparations of both motor and sensory peripheral nerves.

Amyotrophic choreo-acanthocytosis: a new observation in southern Europe

Amyotrophic choreo-acanthocytosis is a rare disease of adult onset characterized by dyskinesias, neurogenic muscular atrophy, erythrocytary acanthocytosis with normal serum lipoproteins and elevated levels of serum CPK. Presumably, this disorder is an autosomal recessively inherited trait. This disease has been described in Japanese, English, Finnish and Puerto Rican people. This is the first observation in the southern countries of Europe, in two members of a Calabrian family. The authors point out that amyotrophic features can occur several years before the appearance of the extrapyramidal disorders.

Erythrocyte membrane abnormalities in patients with amyotrophic chorea with acanthocytosis. Part 1. Spin labeling studies and lipid analyses

Low fluidity was observed in the erythrocyte membranes of familial chorea-acanthocytosis by spin labeling with 12NS. The high content of the saturated fatty acids support the finding of low fluidity. Other lipid contents (cholesterol and phospholipids) and the cholesterol/phospholipid ratio were within normal ranges. The sharp decrease in the parameter, (h0/h-1)1/2, suggests phase separation deep inside the patients' erythrocyte membrane matrix. This distortion of the membrane matrix may be caused by membrane components other than the lipid components.

Chorea-acanthocytosis. Neurological disease with acanthocytosis

A case of chorea-acanthocytosis (CA) syndrome is described. CA is a rare, inherited syndrome characterized by normolipoproteinemic acanthocytosis and progressive neurological disturbances (orofacial dyskinesia, limb chorea, lip and tongue biting, distal muscle wasting, muscle hypotonia, absent or diminished tendon reflexes) with adult onset. Thus far, 10 independent reports of CA have been published. The present case is the first patient reported in Europe outside Great Britain. Due to obvious clinical similarities between CA and Huntington's chorea, particular attention is drawn to the differential diagnosis between these 2 syndromes. Investigation of the red blood cell morphology should necessarily be performed in the examination of choreic patients, particularly when the disorder is familial.