Chronic inflammatory demyelinating polyneuropathy as a complication of cat scratch disease

Item does not contain fulltex

Study on the gene and phenotypic characterisation of autosomal recessive demyelinating motor and sensory neuropathy (Charcot-Marie-Tooth disease) with a gene locus on chromosome 5q23-q33

OBJECTIVES—To report the occurrence of the autosomal recessive form of demyelinating Charcot-Marie-Tooth disease (CMT) with a locus on chromosome 5q23-33 in six non-related European families, to refine gene mapping, and to define the disease phenotype.
METHODS—In an Algerian patient with autosomal recessive demyelinating CMT mapped to chromosome 5q23-q33 the same unique nerve pathology was established as previously described in families with a special form of autosomal recessive demyelinating CMT. Subsequently, the DNA of patients with this phenotype was tested from five Dutch families and one Turkish family for the 5q23-q33 locus.
RESULTS—These patients and the Algerian families showed a similar and highly typical combination of clinical and morphological features, suggesting a common genetic defect. A complete cosegregation for markers D5S413, D5S434, D5S636, and D5S410 was found in the families. Haplotype construction located the gene to a 7 cM region between D5S643 and D5S670. In the present Dutch families linkage disequilibrium could be shown for various risk alleles and haplotypes indicating that most of these families may have inherited the underlying genetic defect form a common distant ancestor.
CONCLUSIONS—This study refines the gene localisation of autosomal recessive demyelinating CMT, mapping to chromosome 5q23-33 and defines the phenotype characterised by a precocious and rapidly progressive scoliosis in combination with a relatively mild neuropathy and a unique pathology. Morphological alterations in Schwann cells of the myelinated and unmyelinated type suggest the involvement of a protein present in both Schwann cell types or an extracellular matrix protein rather than a myelin protein. The combination of pathological features possibly discerns autosomal recessive demyelinating CMT with a gene locus on chromosome 5q23-33 from other demyelinating forms of CMT disease.


SH3TC2/KIAA1985 protein is required for proper myelination and the integrity of the node of Ranvier in the peripheral nervous system

Charcot–Marie–Tooth disease type 4C (CMT4C) is an early-onset, autosomal recessive form of demyelinating neuropathy. The clinical manifestations include progressive scoliosis, delayed age of walking, muscular atrophy, distal weakness, and reduced nerve conduction velocity. The gene mutated in CMT4C disease, SH3TC2/KIAA1985, was recently identified; however, the function of the protein it encodes remains unknown. We have generated knockout mice where the first exon of the Sh3tc2 gene is replaced with an enhanced GFP cassette. The Sh3tc2ΔEx1/ΔEx1 knockout animals develop progressive peripheral neuropathy manifested by decreased motor and sensory nerve conduction velocity and hypomyelination. We show that Sh3tc2 is specifically expressed in Schwann cells and localizes to the plasma membrane and to the perinuclear endocytic recycling compartment, concordant with its possible function in myelination and/or in regions of axoglial interactions. Concomitantly, transcriptional profiling performed on the endoneurial compartment of peripheral nerves isolated from control and Sh3tc2ΔEx1/ΔEx1 animals uncovered changes in transcripts encoding genes involved in myelination and cell adhesion. Finally, detailed analyses of the structures composed of compact and noncompact myelin in the peripheral nerve of Sh3tc2ΔEx1/ΔEx1 animals revealed abnormal organization of the node of Ranvier, a phenotype that we confirmed in CMT4C patient nerve biopsies. The generated Sh3tc2 knockout mice thus present a reliable model of CMT4C neuropathy that was instrumental in establishing a role for Sh3tc2 in myelination and in the integrity of the node of Ranvier, a morphological phenotype that can be used as an additional CMT4C diagnostic marker

Severe Dejerine-Sottas disease with respiratory failure and dysmorphic features in association with a PMP22 point mutation and a 3q23 microdeletion

Item does not contain fulltex

Shortened internodal length of dermal myelinated nerve fibres in Charcot–Marie-Tooth disease type 1A

Charcot–Marie-Tooth disease type 1A is the most common inherited neuropathy and is caused by duplication of chromosome 17p11.2 containing the peripheral myelin protein-22 gene. This disease is characterized by uniform slowing of conduction velocities and secondary axonal loss, which are in contrast with non-uniform slowing of conduction velocities in acquired demyelinating disorders, such as chronic inflammatory demyelinating polyradiculoneuropathy. Mechanisms responsible for the slowed conduction velocities and axonal loss in Charcot–Marie-Tooth disease type 1A are poorly understood, in part because of the difficulty in obtaining nerve samples from patients, due to the invasive nature of nerve biopsies. We have utilized glabrous skin biopsies, a minimally invasive procedure, to evaluate these issues systematically in patients with Charcot–Marie-Tooth disease type 1A (n = 32), chronic inflammatory demyelinating polyradiculoneuropathy (n = 4) and healthy controls (n = 12). Morphology and molecular architecture of dermal myelinated nerve fibres were examined using immunohistochemistry and electron microscopy. Internodal length was uniformly shortened in patients with Charcot–Marie-Tooth disease type 1A, compared with those in normal controls (P < 0.0001). Segmental demyelination was absent in the Charcot–Marie-Tooth disease type 1A group, but identifiable in all patients with chronic inflammatory demyelinating polyradiculoneuropathy. Axonal loss was measurable using the density of Meissner corpuscles and associated with an accumulation of intra-axonal mitochondria. Our study demonstrates that skin biopsy can reveal pathological and molecular architectural changes that distinguish inherited from acquired demyelinating neuropathies. Uniformly shortened internodal length in Charcot–Marie-Tooth disease type 1A suggests a potential developmental defect of internodal lengthening. Intra-axonal accumulation of mitochondria provides new insights into the pathogenesis of axonal degeneration in Charcot–Marie-Tooth disease type 1A