Natural history of Charcot-Marie-Tooth 2: 2-year follow-up of muscle strength, walking ability and quality of life.

Charcot-Marie-Tooth (CMT) disease is the most frequent inherited neuropathy, no therapies are available at the moment but clinical trials are ongoing. For that reason it is very important to know the natural history of the disease. We report the results of the natural history of clinical features and quality of life (QoL) in patients with CMT2. Twenty patients were enrolled. At recruitment and at follow-up (2 years), all patients underwent neurological evaluation, QoL and disability assessments. The study-end evaluation took place 20-28 months after the baseline evaluation. During the 2-year follow-up period, CMT2 patients showed a mild reduction of strength of distal muscles of upper limbs and proximal muscles of lower limbs, a worsening sensory function and a mild increase in walking disability. However, there was no relevant worsening of QoL, except for a mild deterioration of one mental health domain.

Evaluating endothelial function of the common carotid artery: an in vivo human model.

BACKGROUND AND AIMS: Flow mediated dilation (FMD) of peripheral conduit arteries is a well-established tool to evaluate endothelial function. The aims of this study are to apply the FMD model to cerebral circulation by using acetazolamide (ACZ)-induced intracranial vasodilation as a stimulus to increase common carotid artery (CCA) diameter in response to a local increase of blood flow velocity (BFV). METHODS AND RESULTS: In 15 healthy subjects, CCA end-diastolic diameter and BFV, middle cerebral artery (MCA) BFV and mean arterial blood pressure (MBP) were measured at basal conditions, after an intravenous bolus of 1g ACZ, and after placebo (saline) sublingual administration at the 15th and 20th minute. In a separate session, the same parameters were evaluated after placebo (saline) infusion instead of ACZ and after 10 microg/m(2) bs and 300 microg of glyceryl trinitrate (GTN), administered sublingually, at the 15th and 20th minute, respectively. After ACZ bolus, there was a 35% maximal MCA mean BFV increment (14th minute), together with a 22% increase of mean CCA end-diastolic BFV and a CCA diameter increment of 3.9% at the 3rd minute (p=0.024). There were no MBP significant variations up to the 15th minute (p=0.35). After GTN administration, there was a significant increment in CCA diameter (p<0.00001). CONCLUSIONS: ACZ causes a detectable CCA dilation in healthy individuals concomitantly with an increase in BFV. Upon demonstration that this phenomenon is endothelium dependent, this experimental model might become a valuable tool to assess endothelial function in the carotid artery.

Cerebral autosomal dominant arteriopathy with subcortical infarcts and leucoencephalopathy and right-to-left shunt: lack of evidence for an association in a prevalence study.

BACKGROUND/AIMS: Up to more than 50% of cryptogenetic stroke patients and patients with migraine with aura (MA) are found to have a right-to-left shunt (RLS), which is usually due to a patent foramen ovale. Moreover, both MA and stroke are cardinal features of cerebral autosomal dominant arteriopathy with subcortical infarcts and leucoencephalopathy (CADASIL). Notch3 mutations have been suggested to induce an abnormally high incidence of atrial septal defects in a family harbouring an Arg141Cys pathogenetic mutation. We sought to determine the prevalence of RLS in CADASIL patients with different Notch3 mutations, both with and without migraine as a clinical feature. METHODS: Subjects with a molecular diagnosis of CADASIL were tested for the presence of an RLS by means of contrast-enhanced transcranial Doppler (TCD). The diagnosis of migraine was made according to the 2004 International Headache Classification. RESULTS: Sixteen CADASIL patients were tested; 6 had MA. Four patients displayed an RLS on contrast-enhanced TCD examination. Three of these patients had MA. Both patients with Arg141Cys displayed a large RLS. CONCLUSION: We conclude that RLS is not necessarily linked to CADASIL as a comorbidity factor. Nevertheless, there could be a relation between RLS and specific Notch3 mutations, such as Arg141Cys.

Natural history of CMT1A including QoL: a 2-year prospective study.

The Italian CMT study group performed a multicentre, multidimensional, longitudinal 2-year follow-up study using validated measurements of neurological impairment, disability and quality of life. The aim of the study was to evaluate the natural history of clinical features, disability and QoL in patients with CMT1A. On clinical examination, CMT1A patients showed a significant reduction in muscle strength and sensory function during the 2-year follow-up period. However, there was no worsening of QoL or disability, nor was depression observed. The discrepancy between the evolution of clinical features and the evolution of QoL and disability may be due to the development of compensatory strategies that help patients cope with the slow progression of the disease. Our observations provide information which may be useful when designing clinical trials in CMT.

Stereotactic brain biopsy in human immunodeficiency virus-infected patients.

OBJECTIVE: To evaluate prospectively the diagnostic efficacy and safety of stereotactic brain biopsy and its impact on treatment, outcome, and survival in human immunodeficiency virus-infected patients with focal brain lesions. METHODS: Computed tomography-guided stereotactic brain biopsy was performed in 26 patients, of whom 17 failed to respond to a 2- to 3-week anti- Toxoplasma regimen. Exclusion criteria for biopsy were overt acquired immunodeficiency syndrome for 2 years or longer, Karnofsky score less than 50, and severe coagulopathies. RESULTS: A definitive diagnosis was obtained in 24 patients (92%), of whom 12 (46%) had primary brain lymphoma, six (23%) had progressive multifocal leukoencephalopathy, and four (15%) had Toxoplasma encephalitis. Two thirds of contrast-enhancing lesions on computed tomography were lymphoma and three fourths of contrast-negative lesions were leukoencephalopathy. Three patients had biopsy-related cerebral hemorrhages (morbidity, 11.5%). Median follow-up and survival for the entire group were 24 weeks (range, 6 to 135 weeks). Twenty patients (77%) received specific therapy and 13 (50%) responded to treatment. Of 11 patients with lymphoma undergoing irradiation treatment (whole-brain radiotherapy in seven and gamma-knife treatment in four), nine (82%) had clinical and radiologic response, with a median survival of 34 weeks (range, 13 to 57 weeks). CONCLUSIONS: Stereotactic brain biopsy has high diagnostic efficacy and clinical benefit in carefully selected human immunodeficiency virus-infected patients. The procedure should be performed essentially in patients with contrast-enhancing lesions on computed tomography who have a high frequency of treatable cerebral diseases.

Detection of mutations in the ALD gene (ABCD1) in seven Italian families: description of four novel mutations.

The study describes the mutations causing adrenoleukodystrophy in seven Italian families. Four missense mutations leading to amino acid substitutions, two frameshift mutations leading to a premature termination signal, and a splicing mutation were identified. Mutations 2014C>T (P543L), 2053A>G (Q556A), 673-674insCC, and 1874+1G>A are described for the first time in this report. Mutations 1638C>T (R418W), 1588G>A(R401Q), and 1801-1802delAG are already known to be link to ALD.

Charcot-Marie-Tooth disease type I and related demyelinating neuropathies: Mutation analysis in a large cohort of Italian families.

Charcot-Marie-Tooth neuropathy type 1 (CMT1), the most common hereditary neurological disorder in humans, is characterized by clinical and genetic heterogeneity. It is caused mainly by a 1.5 Mb duplication in 17p11.2, but also by mutations in the myelin genes PMP22 (peripheral myelin protein 22), MPZ (myelin protein zero), Cx32 (connexin 32; also called GJB1), and EGR2 (early growth response 2). In this study, we have screened 172 index cases of Italian families in which there was at least one subject with a CMT1 diagnosis for the duplication on 17p11.2 and mutations in these genes. Among 170 informative unrelated patients, the overall duplication frequency was 57.6%. A difference could be observed between the duplication frequency in familial cases (71.6%) and that observed in non-familial cases (36.8%). Among the non-duplicated patients, 12 were mutated in Cx32, four in MPZ, two in PMP22, and none in the EGR2. In the non-duplicated cases, the overall point mutation frequency for these genes was 25.0%. We describe the mutations identified, and consider possible genotype-phenotype correlation.

Nuroaxonal degeneration induced by sodium diethyldithiocarbamate in cultures of central nervous tissue.

Well myelinated cultures of newborn mouse cerebellum, exposed to varying concentrations of sodium diethyldithiocarbamate (DDC), a heavy metal chelating agent, were examined by light and electron microscopy. DDC treatment of cultures for 24-48 hours produced swellings of axons and presynaptic endings, the morphological features characteristic of dystrophic axons. The axonal swellings contained an increased amount of endoplasmic reticulum, mitochondria and dense bodies. A continued exposure to DDC induced an extensive degeneration of axons and ensheathing myelin. Glial cells, on the other hand, were structurally intact even after a long-term exposure to DDC. It is suggested that DDC produces in myelinated CNS cultures an initial enlargement of axons and presynaptic endings and then continues to induce Wallerian degeneration in axons.

Inherited neuroaxonal dystrophy in C6 deficient rabbits.

We report the occurrence of a progressive neurological syndrome clinically characterized by subacute motor neuropathy in offspring of C6 deficient rabbits. On the basis of the pedigree analysis, the disease appears to be genetically transmitted, most probably with an autosomal recessive mode of inheritance. Pathological studies of affected animals revealed: transmitted, most probably with an autosomal recessive mode of inheritance. Pathological studies of affected animals revealed: 1) severe axonal degeneration in the sciatic nerve system involving mainly motor fibers; 2) occasional peripheral axonal enlargement closely associated with axonal degeneration; 3) presence of structured abnormal material in normal-size myelinated fibers of central nervous system (CNS) and peripheral nervous system (PNS); and 4) widespread occurrence of dystrophic axons and axonal spheroids in the gray matter of CNS. By ultrastructural examination, dystrophic axons are filled with tubulovesicular material, stalks of parallel membranes and dense bodies similar to what is described in human neuroaxonal dystrophies (NAD). The disease manifested by C6 deficient rabbits may represent an animal model of primary human NAD.

Experimental induction of myelin changes by anti-MAG antibodies and terminal complement complex.

We investigated the role of anti-myelin-associated glycoprotein (MAG) IgM and complement (C) in the pathogenesis of myelin alterations occurring in patients with anti-MAG-associated polyneuropathy. For this purpose, we separately studied the effects of anti-MAG antibodies and terminal C complex (TCC) after injection into the rabbit sciatic nerve. The two different local treatments produced identical ultrastructural abnormalities such as intramyelinic edema, myelin vesiculation and, in particular, separation of the major dense lines with the formation of widely spaced myelin, a peculiar feature encountered in human peripheral nerve disorders with circulating anti-myelin monoclonal IgM. In nerves treated with anti-MAG IgM ultrastructural myelin alterations were concurrent with activation of the rabbit's own C to the formation of TCC. Contrary to the immunological and ultrastructural findings obtained in C-sufficient animals, in C6-deficient rabbits injected with anti-MAG IgM no myelin alterations nor C completion were observed. This study identifies anti-MAG IgM as the mediator and the C as the effector of myelin changes observed in the present model and, for extension, in human neuropathies associated with anti-MAG IgM.

Increased expression of the normal cellular isoform of prion protein in inclusion-body myositis, inflammatory myopathies and denervation atrophy.

The cellular isoform of the prion protein (PrPc) is a glycosylphosphatidylinositol-anchored glycoprotein, normally expressed in neural and non-neural tissues, including skeletal muscle. In transmissible spongiform encephalopathies, or prion diseases, PrPc, which is soluble in nondenaturing detergent and sensitive to proteinase K (PK)-treatment, represents the molecular substrate for the production of a detergent-insoluble and PK-resistant isoform, termed PrP(Sc). In human prion diseases, PrP(Sc) accumulation occurs only in brain tissues, with the exception of new variant Creutzfeldt-Jakob disease, where PrP(Sc) is also detected in lymphoid tissues. Increased amounts of prion protein expression and deposition have been described in pathological muscle fibers of two human muscle disorders, called sporadic inclusion-body myositis (s-IBM) and hereditary inclusion-body myopathy, but it is unknown whether accumulated prion protein reflects normal PrPc or PrP(Sc). We investigated the biochemical characteristics of prion protein in normal human muscle, s-IBM, other inflammatory myopathies and denervation atrophy. We report that 1) both the glycoform profile and size of the normal muscle PrPc are different from those of human brain PrPc; 2) in addition to s-IBM, increased PrPc expression is seen in polymyositis, dermatomyositis and neurogenic muscle atrophy, but PrPc glycoforms are unchanged; 3) only the normal PrPc isoform, and not PrP(Sc), is detected in s-IBM. The present results exclude that s-IBM is a prion disease.

Motor neuron disease with pyramidal tract dysfunction involves the cortical generators of the early somatosensory evoked potential to tibial nerve stimulation.

We evaluated somatosensory evoked potentials (SEPs) to tibial nerve stimulation in 39 patients with sporadic motor neuron disease using multiple scalp derivations (earlobe reference). SEPs were altered in 22 of 29 amyotrophic lateral sclerosis (ALS) patients, whereas they were unaffected in 10 progressive muscular atrophy (PMA) patients. The main changes involved the amplitude and the field distribution of the early P40 and N37 cortical potentials with different modalities varying from a selective loss of the P40 potential (33% of tested sides) to absence of all early cortical SEPs (22% of tested sides). The later components following N50 were generally spared. The commonly used Cz-Fz montage was inadequate for detecting these alterations. Central afferent conduction was slightly affected. The selective loss of cortical SEPs and their close correlation with clinicoelectrophysiologic evidence of central motor system involvement strongly support a cortical origin of the SEP alterations in ALS. We suggest that neuronal loss in the somatosensory cortex may selectively affect the generator sites of the cortical SEPs to lower limb stimulation.

A somatic and germline mosaic mutation in MPZ/P(0) mimics recessive inheritance of CMT1B.

OBJECTIVE: To identify the molecular basis of a demyelinating Charcot-Marie-Tooth disease type 1 (CMT1) with presumed autosomal recessive inheritance. BACKGROUND: CMT1, an inherited motor and sensory neuropathy with low nerve conduction velocities, is caused by dominantly inherited mutations in the genes of the peripheral myelin protein 22 (PMP22), myelin protein zero (MPZ/P(0)), and early growth response 2 transcription factor (EGR2/Krox-20). PATIENTS AND METHODS: Two young sisters born of clinically and electrophysiologically healthy parents had a severe CMT1 neuropathy of presumed autosomal recessive inheritance. The older sister underwent a nerve biopsy. The authors analyzed PMP22, MPZ/P(0), and EGR2/Krox-20 by automated direct nucleotide sequencing. For rapid mutation detection, they determined the restriction-fragment-length polymorphisms for TaqI in the fluorescein-labeled target DNA sequence amplified by PCR. RESULTS: Nerve biopsy disclosed a demyelinating and remyelinating neuropathy with onion bulb formations. Both sisters had a novel heterozygous G308-->A transition of MPZ/P(0) without any mutation of PMP22 or EGR2/Krox-20. The G308-->A transition was a nonconservative mutation that changed a glycine into a glutamate at the amino acid residue 74 in the extracellular domain of the mature MPZ/P(0). None of 50 healthy controls had the mutation. The healthy mother had a low amount of the mutation in blood (congruent with 20%) as well as in skin, buccal epithelium, and hairs (30%). Because the healthy mother carried clones of somatic mutant cells and had transmitted the G308-->A transition to the affected daughters, she also harbored germline mutant cells. CONCLUSION: In hereditary demyelinating neuropathies, somatic and germline mosaicism of dominant mutations in the myelin protein genes may mimic autosomal recessive inheritance.

Myelin uncompaction in Charcot-Marie-Tooth neuropathy type 1A with a point mutation of peripheral myelin protein-22.

BACKGROUND: The peripheral myelin protein-22 (PMP22) gene has four transmembrane domains, two extracellular loops, and a short cytoplasmic tail. Its roles in the peripheral nervous system remain unclear. The most common cause of Charcot-Marie-Tooth neuropathy type 1A (CMT1A) is a PMP22 gene duplication. Missense point mutations in the transmembrane domains are rare alternative causes that have undetermined pathogenetic mechanisms. OBJECTIVE: To investigate the phenotype-to-genotype correlations in a pedigree with unusual CMT1A. METHODS: We identified a pedigree with an autosomal dominant motor-sensory neuropathy and severely reduced nerve conduction velocities who did not have the PMP22 duplication. Specimens from sural nerve biopsies from two patients of different ages were evaluated morphometrically. By automated direct nucleotide sequencing we analyzed PMP22 and the gene of the major structural myelin protein zero (P0). RESULTS: Nucleotide 159 of PMP22 showed an A-to-T heterozygous mutation, predicted to cause an aspartate-to-valine substitution at codon 37 in the first extracellular loop of the protein. The mutation co-segregated with the disease in the pedigree and was absent in 80 healthy controls. The histopathologic phenotype was a de-remyelinating neuropathy with onion bulb formations, characterized by prominent uncompaction of the myelin sheath in the majority of fibers and by frequent tomacula. CONCLUSION: We have described a novel mutation in the first extracellular loop of PMP22 associated with an atypical CMT1A that overlaps pathologically with CMT1B caused by point mutations in the extracellular domain of P0.

Polyneuropathy in hypereosinophilic syndrome.

We investigated two patients with the idiopathic hypereosinophilic syndrome and peripheral neuropathy. Clinical, EMG, and pathological findings were consistent with axonal polyneuropathy. Morphologic changes of the nerve biopsies suggested axonal damage secondary to increased endoneurial pressure from leakage of capillaries. We postulate that endothelial cell damage, followed by nerve edema, is the first step in the pathogenesis of peripheral neuropathy in these patients.

Polyglucosan body myopathy: a new case.

We report a 51-yr-old woman with late-onset progressive weakness affecting proximal limb muscles. Muscle biopsy revealed a vacuolar myopathy with accumulation of amylopectin-like polysaccharide resembling the polyglucosan found in type IV glycogenosis and adult-onset polyglucosan body disease. A biochemical study ruled out specific enzymatic defects known to cause storage of this abnormal material. Our case confirms the existence of a 'polyglucosan body myopathy' as a distinct clinicopathological entity in which the biochemical defect is unknown.

A new mutation in the mitochondrial tRNA(Ala) gene in a patient with ophthalmoplegia and dysphagia.

We describe a new mutation in the tRNA(Ala) gene, a T-->C transition at nucleotide position 5628, in a 62-year-old woman with late onset chronic progressive external ophthalmoplegia, dysphagia and mild proximal myopathy. The mutation is heteroplasmic and disrupts a highly conserved A-U base pair within the anticodon stem of the tRNA(Ala). Cytochrome c oxidase-negative fibers harbor a significantly higher level of mutated mtDNA than cytochrome c oxidase-positive fibers. This is the first mutation in the tRNA(Ala) gene which satisfies accepted criteria for pathogenicity.

Hepatitis C virus infection and myositis: a virus localization study.

We report a case of myositis associated with chronic hepatitis C virus infection. Muscle biopsy and immunohistochemistry showed perifascicular atrophy, few necrotic and regenerating fibres, scarce perivascular infiltrates, deposits of immunoglobulin G, C3, fibrinogen and MAC in muscle vessel walls, and non-uniform expression of major histocompatibility complex-I antigens among muscle fibres. Hepatitis C virus NS3 antigen and hepatitis C virus RNA were detected in infiltrating cells but not within muscle fibres or endothelial cells. Our findings suggest that humoral-mediated immune mechanisms, not directly related to hepatitis C virus infection of muscle structures, may sustain the local inflammatory reaction in this patient.

Congenital hypomyelination neuropathy with Ser72Leu substitution in PMP22.

We describe a patient with congenital hypomyelination neuropathy. The pathological and morphometrical findings in the sural nerve biopsy were consistent with a defect of myelin formation and maintenance. Direct sequence analysis of the genomic regions coding the peripheral myelin proteins P0 and PMP22 disclosed a heterozygous missense point mutation that leads to a Ser72Leu substitution in the second transmembrane of PMP22. Codon 72 mutations of PMP22 are associated with different phenotypes encompassing the Dejerine-Sottas syndrome and including congenital hypomyelination neuropathy.

Systemic passive transfer studies using IgM monoclonal antibodies to sulfatide.

We present a patient with benign IgM-gamma anti-Sulfatide (SUL) whose neuropathy was transferred in newborn rabbits. The patient's clinico-pathological picture of anti-SUL-associated demyelinating neuropathy is reported. The monoclonal IgM antibodies prepared by Tatum's method, that retained their biological activity, were passively transferred to newborn rabbits. The passive transfer produced demyelinating nerve lesions very similar to the donor antibody neuropathy. In experimental lesions we observed the human IgM anti-SUL antibodies binding to Schmidt-Lanterman incisures and nodes of Ranvier. We postulate that the myelin-specific and complement-dependent lesions observed in the peripheral nerve support the potential demyelinating role of anti-SUL antibodies. Moreover, the pattern of the antibody binding to the perineuronal sheath of satellite cells in dorsal root ganglia strengthen the hypothesis that anti-SUL antibodies may have a pathogenetic role in this sensorimotor syndrome.