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Amyloid gets its name from the starchy, amorphous appearance of amyloid deposits under the microscope. In amyloidosis, these deposits are found in numerous organs as well as the peripheral nerves, which are commonly affected along their entire length. The amyloid deposits lead to degeneration in organs such as the liver and kidneys. In cases with nerve involvement, biopsy of the distal portion of the nerve reveals amyloid deposits, demyelination (loss of the myelin sheath covering the nerve), and loss of nerve fibers. A case is now reported in which deposits of amyloid appear to be limited to the lumbosacral (lower back) nerve roots and plexus (network of nerves). The patient was a 25-year-old man who developed weakness in the right leg. After 20 months, similar symptoms appeared in the left leg as well. Examination with lumbar myelography (an X-ray technique) revealed that the nerve roots at L-5 and S-1 were enlarged (the fifth lumbar and first sacral vertebrae). Biopsy of the left and right superficial peroneal nerves (which innervate the leg) did not reveal any indications of amyloid deposition, but an analysis of the nerve fibers indicated that smaller myelinated nerve fibers were absent and that the entire size distribution of myelinated fibers was shifting to smaller diameters. These findings suggested atrophy of the nerves. When a biopsy of the lumbosacral nerve plexus was performed, similar signs of nerve degeneration were observed. In addition, amyloid was deposited throughout the endoneurium (connective tissue covering nerve fibers). Inflammatory cells were noted near the amyloid and severe edema had disrupted the structure of the plexus. This disruption was apparently responsible for the enlarged appearance of the nerve roots as seen on myelography. The relationship of this case to the syndrome of amyloidosis, as it is known, is not certain. The amyloid deposits seen in this case were not immunohistochemically stained with antibodies to serum amyloid A, prealbumin, or immunoglobulin light chains. The authors are not certain, however, whether this indicates the absence of these antigens in the observed amyloid or some technical difficulty with the staining procedure. (Consumer Summary produced by Reliance Medical Information, Inc.)

A 4 year old girl had been hypotonic and areflexic since birth with delayed milestones in motor development. Repetitive stimulation at high rates performed at 3 years elicited an incremental response typical of the Lambert-Eaton Syndrome. [ABSTRACT FROM AUTHOR]

A 26-year-old male with a history of pulmonary sarcoidosis showed clinical, myelographic and intra-operative evidence of a C5-C6 spinal cord tumour, which was diagnosed by biopsy as a pure intramedullary granuloma. Among the 29 published cases of histologically proven cord sarcoidosis, only five presented with pure parenchymatous infiltration without meningeal involvement. Corticosteroids are the most useful therapy, and surgery is indicated only for minimal biopsy when the parenchyma is invaded. [ABSTRACT FROM AUTHOR]

Limb-girdle muscular dystrophies (LGMDs) are a group of neuromuscular diseases presenting great clinical heterogeneity. Mutations in CANP3, the gene encoding muscle-specific calpain, were used to identify this gene as the genetic site responsible for autosomal recessive LGMD type 2A (LGMD2A; MIM 253600). Analyses of the segregation of markers flanking the LGMD2A locus and a search for CANP3 mutations were performed for 21 LGMD2 pedigrees from various origins. In addition to the 16 mutations described previously, we report 19 novel mutations. These data indicate that muscular dystrophy caused by mutations in CANP3 are found in patients from all countries examined so far and further support the wide heterogeneity of molecular defects in this rare disease.

We report three cases presenting mainly with neck extensor weakness, or dropped head syndrome, revealing respectively myasthenia gravis, amyotrophic lateral sclerosis and non-inflammatory neck extensors myopathy. We discuss the different diagnosis of this rare syndrome and this late onset localized myopathy of unknown etiology.

Carpal tunnel syndrome is the most frequent entrapment neuropathy. Nerve conduction studies and electromyography are useful to appreciate the localization and the degree of nerve involvement, and help to the therapeutic management. Various electrophysiological procedures may be used and are reviewed. For each of them, positive (sensitivity and specificity) and negative points (technical difficulties, errors and false positive) are reported. A guideline is proposed.

Hypokalemic periodic paralysis (hypoPP) is an autosomal dominant disorder belonging to a group of muscle diseases involving the abnormal function of ion channels. This group of muscle diseases also comprises hyperkalemic periodic paralysis and paramyotonia congenita, both sodium-channel diseases, and myotonia congenita, a chloride-channel disorder. HypoPP is characterized by acute attacks of muscle weakness concomitant with a fall in blood potassium levels. We recently localized the hypoPP locus (hypoPP1) to chromosome 1q31-32, in an interval where the alpha 1 subunit of the dihydropyridine receptor calcium channel (CACNL1A3) also maps. Subsequently, deleterious mutations in the voltage-sensor segment S4 were found, establishing the dihydropyridine receptor CACNL1A3 as the causative gene for hypoPP. In this paper, we report the study of 16 hypoPP families of Caucasian origin. We found only two mutations--Arg528His and Arg1239His--that cosegregated with hypoPP, each in half of the families. Analysis of the clinical characteristics of both groups of families demonstrated that incomplete penetrance is a distinctive feature of the Arg528His mutation. Using dinucleotide repeats contained within or close to the dihydropyridine receptor gene, in conjunction with evidence of a de novo Arg1239His mutation, we show that a founder effect is unlikely to account for the two predominant mutations.

Carpal tunnel syndrome (CTS) is very uncommon in childhood. Sixty-five cases are reported in the literature, principally due to metabolic diseases. In Mucopolysaccharidoses, prospective studies (Wraith and Alani, 1990) found a bilateral CTS in about 90%. We report four cases of Mucopolysaccharidoses, diagnosed on clinical and biological data (two cases of Hurler disease, and two cases of Hunter disease), in children aged less than five years. Each child had claw hands, without thenar atrophy. Median nerve conduction studies and electromyography confirm the CTS. Motor and sensory nerve conductions are normal in other nerves. Concentric needle studies show in two cases, on abductor pollicis brevis, spontaneous activities as repetitive discharges, fasciculations and multiplets. Median nerve stimulations reveal responses with late potentials during 70 ms due to reinnervation. The physiopathology of those carpal tunnel syndromes is discussed.

A myasthenic syndrome was diagnosed in 3 female patients aged 37, 47 and 56 years. The symptoms were first noticed in childhood, and at 16 and 25 years. Respectively weakness and atrophy of finger extensor muscles were present in all patients. In 2 of them scapular and cervical muscles were involved. Weakness was markedly increased by cold in every patient. Similar symptoms were noted in first degree relatives in all cases. Single nerve stimulus elicited a repetitive compound muscle action potential in hand muscles. Repetitive nerve stimulation induced a myasthenic decrement in finger extensor muscles. SFEMG studies demonstrated increased jitter with frequent blockings. Genetic, clinical and electrodiagnostic data were consistent with the hypothesis of the so-called "Slow-Channel" myasthenic syndrome. As 2 of these patients were considered to have "unknown myopathy" the use of careful nerve stimulation tests is advocated in such cases.

The authors report two cases of Lambert-Eaton myasthenic syndrome associated with small cell lung carcinoma. Following the observations, the clinical diagnosis of this syndrome is considered. We discuss the autoimmune pathogenesis and the relation between paraneoplastic syndrome and small cell cancer. This syndrome is caused by autoantibodies that block the voltage-dependent calcium channels at motor nerve terminals. Small cell carcinoma cells appear to express calcium channels, suggesting that autoantibody production may be triggered by tumor calcium channels determinants. The autoimmune paraneoplastic syndrome theory refers to cross-antigenicity.