A phase II-III trial of olesoxime in subjects with amyotrophic lateral sclerosis.

BACKGROUND AND PURPOSE: To assess the efficacy and safety of olesoxime, a molecule with neuroprotective properties, in patients with amyotrophic lateral sclerosis (ALS) treated with riluzole. METHODS: A double-blind, randomized, placebo-controlled, multicenter trial of 18 months' duration was conducted in 512 subjects, with probable or definite ALS and a slow vital capacity (SVC) ≥70%, receiving 330 mg olesoxime daily or matching placebo and 50 mg riluzole twice a day in all. The primary intention-to-treat (ITT) outcome analysis was 18 months' survival. Secondary outcomes were rates of deterioration of the revised ALS functional rating scale (ALSFRS-R), focusing on the 9-month assessment, SVC and manual muscle testing. Blood levels, safety and tolerability of olesoxime were also assessed. RESULTS: At 18 months, 154 of the 512 ITT patients had died (79 of 253 placebo, 75 of 259 olesoxime). Estimated overall survival according to Kaplan-Meier analysis was 67.5% (95% CI 61.0%-73.1%) in the placebo group and 69.4% (95% CI 63.0%-74.9%) in the olesoxime group; hence survival was not significantly different between treatment arms (P = 0.71, stratified bulbar/spinal log-rank). The other efficacy end-points evaluated were also negative, with the exception of a small difference in ALSFRS-R global score at 9 months in favor of olesoxime but not sustained after 18 months' treatment nor evident in either the stratified bulbar or spinal subpopulations. Treatment did not raise any safety concerns. CONCLUSIONS: Olesoxime, although well tolerated, did not show a significant beneficial effect in ALS patients treated with riluzole.

Deletion of the hypoxia-response element in the vascular endothelial growth factor promoter causes motor neuron degeneration.

Hypoxia stimulates angiogenesis through the binding of hypoxia-inducible factors to the hypoxia-response element in the vascular endothelial growth factor (Vegf) promotor. Here, we report that deletion of the hypoxia-response element in the Vegf promotor reduced hypoxic Vegf expression in the spinal cord and caused adult-onset progressive motor neuron degeneration, reminiscent of amyotrophic lateral sclerosis. The neurodegeneration seemed to be due to reduced neural vascular perfusion. In addition, Vegf165 promoted survival of motor neurons during hypoxia through binding to Vegf receptor 2 and neuropilin 1. Acute ischemia is known to cause nonselective neuronal death. Our results indicate that chronic vascular insufficiency and, possibly, insufficient Vegf-dependent neuroprotection lead to the select degeneration of motor neurons.

Response of mouse brain perfusion to hypo- and hyperventilation measured by arterial spin labeling.

We aimed to setup a noninvasive and well-controlled methodology for evaluation of the cerebrovascular response in mice (C57BL/6J; 12 weeks). Therefore we applied a normo-, hypo-, and hyperventilation paradigm combined with arterial spin labeling and monitoring of the expired CO(2) (expCO(2)) (n=7) or arterial pCO(2) (apCO(2)) (n=12). Reducing the tidal volume by 25% and the respiratory rate by 20% resulted in hypercapnia (apCO(2) from 33 ± 6 mmHg to 64 ± 16 mmHg). Increasing the respiratory rate by 25% and the tidal volume by 20% decreased apCO(2) to 22 ± 5 mmHg. Cerebral blood flow (CBF) was 82 ± 21, 163 ± 41 and 64 ± 18 mL/100 g/min during normo, hypo-, and hyperventilation, respectively (midbrain). The correlation of apCO(2) and CBF levels resulted in a cerebrovascular response of 2.7 ± 0.3, 2.1 ± 0.3, 2.1 ± 0.3, and 3.7 ± 0.5 mL/100 g/min/mmHg for midbrain, cortex, hippocampus and thalamus, respectively. As expCO(2) levels were correlated with apCO(2) (r(2)=0.86; n=4) and CBF (r(2)=0.67) a cerebrovascular response based on simultaneously recorded CBF and expCO(2) levels could be derived (3.3 ± 0.5, 2.5 ± 0.4, 3.0 ± 0.4, and 4.5 ± 0.6 mL/100 g/min/mmHg; order as above). A cross-over experiment resulted in similar responses. In conclusion, this protocol allows evaluating basal CBF and cerebrovascular response in mice under well-controlled conditions by simply changing ventilator settings and correlating CBF with apCO(2) and/or simultaneously obtained expCO(2).

Differential contribution of the Na(+)-K(+)-2Cl(-) cotransporter NKCC1 to chloride handling in rat embryonic dorsal root ganglion neurons and motor neurons.

Plasma membrane chloride (Cl(-)) pathways play an important role in neuronal physiology. Here, we investigated the role of NKCC1 cotransporters (a secondary active Cl(-) uptake mechanism) in Cl(-) handling in cultured rat dorsal root ganglion neurons (DRGNs) and motor neurons (MNs) derived from fetal stage embryonic day 14. Gramicidin-perforated patch-clamp recordings revealed that DRGNs accumulate intracellular Cl(-) through a bumetanide- and Na(+)-sensitive mechanism, indicative of the functional expression of NKCC1. Western blotting confirmed the expression of NKCC1 in both DRGNs and MNs, but immunocytochemistry experiments showed a restricted expression in dendrites of MNs, which contrasts with a homogeneous expression in DRGNs. Both MNs and DRGNs could be readily loaded with or depleted of Cl(-) during GABA(A) receptor activation at depolarizing or hyperpolarizing membrane potentials. After loading, the rate of recovery to the resting Cl(-) concentration (i.e., [Cl(-)](i) decrease) was similar in both cell types and was unaffected by lowering the extracellular Na(+) concentration. In contrast, the recovery on depletion (i.e., [Cl(-)](i) increase) was significantly faster in DRGNs in control conditions but not in low extracellular Na(+). The experimental observations could be reproduced by a mathematical model for intracellular Cl(-) kinetics, in which DRGNs show higher NKCC1 activity and smaller Cl(-)-handling volume than MNs. On the basis of these results, we conclude that embryonic DRGNs show a higher somatic functional expression of NKCC1 than embryonic MNs. The high NKCC1 activity in DRGNs is important for maintaining high [Cl(-)](i), whereas lower NKCC1 activity in MNs allows large [Cl(-)](i) variations during neuronal activity.

The occurrence of mutations in FUS in a Belgian cohort of patients with familial ALS.

BACKGROUND AND PURPOSE: Mutations in fused in sarcoma (FUS) were recently identified as a cause of familial amyotrophic lateral sclerosis (ALS). The frequency of occurrence of mutations in FUS in sets of patients with familial ALS remains to be established. METHODS: We sequenced the FUS gene in a cohort of patients with familial ALS seen at the neuromuscular clinic in Leuven. A total of 28 patients with SOD1-negative ALS from 22 families were analyzed. RESULTS: We identified a R521H mutation in 4 patients, belonging to a kindred of dominantly inherited classical ALS. The mutation segregated with disease. Mutations in FUS were observed in 2.9% of ALS pedigrees in our cohort. CONCLUSIONS: These results show that mutations in FUS are also a significant cause of familial ALS in Belgium.

Meta-analysis of vascular endothelial growth factor variations in amyotrophic lateral sclerosis: increased susceptibility in male carriers of the -2578AA genotype.

BACKGROUND: Targeted delivery of the angiogenic factor, vascular endothelial growth factor (VEGF), to motor neurons prolongs survival in rodent models of amyotrophic lateral sclerosis (ALS), while mice expressing reduced VEGF concentrations develop motor neuron degeneration reminiscent of ALS, raising the question whether VEGF contributes to the pathogenesis of ALS. An initial association study reported that VEGF haplotypes conferred increased susceptibility to ALS in humans, but later studies challenged this initial finding. METHODS AND FINDINGS: A meta-analysis was undertaken to critically reappraise whether any of the three common VEGF gene variations (-2578C/A, -1154G/A and -634G/C) increase the risk of ALS. Over 7000 subjects from eight European and three American populations were included in the analysis. Pooled odds ratios were calculated using fixed-effects and random-effects models, and four potential sources of heterogeneity (location of disease onset, gender, age at disease onset and disease duration) were assessed. After correction, none of the genotypes or haplotypes was significantly associated with ALS. Subgroup analysis by gender revealed, however, that the -2578AA genotype, which lowers VEGF expression, increased the risk of ALS in males (OR = 1.46 males vs females; 95% CI = 1.19 to 1.80; p = 7.8 10E-5), even after correction for publication bias and multiple testing. CONCLUSIONS: This meta-analysis does not support the original conclusion that VEGF haplotypes increase the risk of ALS in humans, but the significant association of the low-VEGF -2578AA genotype with increased susceptibility to ALS in males reappraises the link between reduced VEGF concentrations and ALS, as originally revealed by the fortuitous mouse genetic studies.

The role of excitotoxicity in the pathogenesis of amyotrophic lateral sclerosis.

Unfortunately and despite all efforts, amyotrophic lateral sclerosis (ALS) remains an incurable neurodegenerative disorder characterized by the progressive and selective death of motor neurons. The cause of this process is mostly unknown, but evidence is available that excitotoxicity plays an important role. In this review, we will give an overview of the arguments in favor of the involvement of excitotoxicity in ALS. The most important one is that the only drug proven to slow the disease process in humans, riluzole, has anti-excitotoxic properties. Moreover, consumption of excitotoxins can give rise to selective motor neuron death, indicating that motor neurons are extremely sensitive to excessive stimulation of glutamate receptors. We will summarize the intrinsic properties of motor neurons that could render these cells particularly sensitive to excitotoxicity. Most of these characteristics relate to the way motor neurons handle Ca(2+), as they combine two exceptional characteristics: a low Ca(2+)-buffering capacity and a high number of Ca(2+)-permeable AMPA receptors. These properties most likely are essential to perform their normal function, but under pathological conditions they could become responsible for the selective death of motor neurons. In order to achieve this worst-case scenario, additional factors/mechanisms could be required. In 1 to 2% of the ALS patients, mutations in the SOD1 gene could shift the balance from normal motor neuron excitation to excitotoxicity by decreasing glutamate uptake in the surrounding astrocytes and/or by interfering with mitochondrial function. We will discuss point by point these different pathogenic mechanisms that could give rise to classical and/or slow excitotoxicity leading to selective motor neuron death.

Progranulin mutations and amyotrophic lateral sclerosis or amyotrophic lateral sclerosis-frontotemporal dementia phenotypes.

OBJECTIVE: Mutations in the progranulin (PGRN) gene were recently described as the cause of ubiquitin positive frontotemporal dementia (FTD). Clinical and pathological overlap between amyotrophic lateral sclerosis (ALS) and FTD prompted us to screen PGRN in patients with ALS and ALS-FTD. METHODS: The PGRN gene was sequenced in 272 cases of sporadic ALS, 40 cases of familial ALS and in 49 patients with ALS-FTD. RESULTS: Missense changes were identified in an ALS-FTD patient (p.S120Y) and in a single case of limb onset sporadic ALS (p.T182M), although the pathogenicity of these variants remains unclear. CONCLUSION: PGRN mutations are not a common cause of ALS phenotypes.

AMPA receptor calcium permeability, GluR2 expression, and selective motoneuron vulnerability.

AMPA receptor-mediated excitotoxicity is proposed to play a major pathogenic role in the selective motoneuron death of amyotrophic lateral sclerosis. Motoneurons have been shown in various models to be more susceptible to AMPA receptor-mediated injury than other spinal neurons. It has been hypothesized that this selective vulnerability of motoneurons is caused by the expression of highly Ca(2+)-permeable AMPA receptors and a complete or relative lack of the AMPA receptor subunit Glu receptor 2 (GluR2). The aim of this study was to quantify the relative Ca(2+) permeability of AMPA receptors and the fractional expression of GluR2 in motoneurons by combining whole-cell patch-clamp electrophysiology and single-cell RT-PCR and to compare these properties with those of dorsal horn neurons. Spinal motoneurons and dorsal horn neurons were isolated from embryonic rats and cultured on spinal astrocytes. As in previous studies, motoneurons were significantly more vulnerable to AMPA and kainate than dorsal horn neurons. However, all motoneurons expressed GluR2 mRNA ( approximately 40% of total AMPA receptor subunit mRNA), and their AMPA receptors had intermediate whole-cell relative Ca(2+) permeability (P(Ca(2+))/P(Cs(+)) approximately 0. 4). AMPA receptor P(Ca(2+))/P(Cs(+)) and the relative abundance of GluR2 varied more widely in dorsal horn neurons than in motoneurons, but the mean values did not differ significantly between the two cell populations. GluR2 was virtually completely edited at the Q/R site both in motoneurons and dorsal horn neurons. These results indicate that the selective vulnerability of motoneurons to AMPA receptor agonists is not determined solely by whole-cell relative Ca(2+) permeability of AMPA receptors.

Chloride influx aggravates Ca2+-dependent AMPA receptor-mediated motoneuron death.

AMPA receptor-mediated excitotoxicity has been implicated in the pathogenesis of stroke, neurotrauma, epilepsy, and many neurodegenerative diseases such as motoneuron disease. We studied the role of Cl- in AMPA receptor-mediated Ca2+-dependent excitotoxicity in cultured rat spinal motoneurons. Using the gramicidin perforated patch-clamp technique, the intracellular Cl- concentration could be calculated from the reversal potential of the GABA-induced current. The membrane depolarization caused by AMPA receptor stimulation resulted in Cl- influx through 5-nitro-2(3-phenylpropyl-amino) benzoic acid- and niflumic acid-sensitive Cl- channels. Cl- influx during AMPA receptor stimulation aggravated excitotoxic motoneuron death by two mechanisms: an increase of AMPA receptor conductance and an elevation of the Ca2+ driving force through a partial repolarization. The Cl- influx during AMPA receptor stimulation was enhanced by coadministration of GABA. This resulted in an increased Ca2+ influx and an enhanced cell death, suggesting that concomitant GABAergic stimulation may aggravate excitotoxic motoneuron death.

AMPA receptor current density, not desensitization, predicts selective motoneuron vulnerability.

Spinal motoneurons are more susceptible to AMPA receptor-mediated injury than are other spinal neurons, a property that has been implicated in their selective degeneration in amyotrophic lateral sclerosis (ALS). The aim of this study was to determine whether this difference in vulnerability between motoneurons and other spinal neurons can be attributed to a difference in AMPA receptor desensitization and/or to a difference in density of functional AMPA receptors. Spinal motoneurons and dorsal horn neurons were isolated from embryonic rats and cultured on spinal astrocytes. Single-cell RT-PCR quantification of the relative abundance of the flip and flop isoforms of the AMPA receptor subunits, which are known to affect receptor desensitization, did not reveal any difference between the two cell populations. Examination of AMPA receptor desensitization by patch-clamp electrophysiological measurements on nucleated and outside-out patches and in the whole-cell mode also yielded similar results for the two cell groups. However, AMPA receptor current density was two- to threefold higher in motoneurons than in dorsal horn neurons, suggesting a higher density of functional AMPA receptors in motoneuron membranes. Pharmacological reduction of AMPA receptor current density in motoneurons to the level found in dorsal horn neurons eliminated selective motoneuron vulnerability to AMPA receptor activation. These results suggest that the greater AMPA receptor current density of spinal motoneurons may be sufficient to account for their selective vulnerability to AMPA receptor agonists in vitro.

The cellular mRNA expression of GABA and glutamate receptors in spinal motor neurons of SOD1 mice.

ALS is a fatal neurodegenerative disorder characterized by a selective loss of upper motor neurons in the motor cortex and lower motor neurons in the brain stem and spinal cord. About 10% of ALS cases are familial, in 10-20% of these, mutations in the gene coding for superoxide dismutase 1 (SOD1) can be detected. Overexpression of mutated SOD1 in mice created animal models which clinically resemble ALS. Abnormalities in glutamatergic and GABAergic neurotransmission presumably contribute to the selective motor neuron damage in ALS. By in situ hybridization histochemistry (ISH), we investigated the spinal mRNA expression of the GABAA and AMPA type glutamate receptor subunits at different disease stages on spinal cord sections of mutant SOD1 mice and control animals overexpressing wild-type SOD1 aged 40, 80, 120 days and at disease end-stage, i.e. around 140 days) (n=5, respectively). We detected a slight but statistically significant decrease of the AMPA receptor subunits GluR3 and GluR4 only in end stage disease animals.

Mibefradil (Ro 40-5967) blocks multiple types of voltage-gated calcium channels in cultured rat spinal motoneurones.

The actions of the novel calcium (Ca2+) channel antagonist mibefradil (Ro 40-5967), a selective T-type channel blocker in myocardium, were investigated in embryonic rat spinal motoneurones maintained in culture. Whole-cell currents were recorded with the patch-clamp technique. Motoneurones displayed transient, low-voltage-activated (LVA) and, more sustained, high-voltage-activated (HVA) Ca2+ currents. The LVA currents were small and preferentially blocked by amiloride and low doses of nickel. Most of the HVA Ca2+ current flowed through N-type Ca2+ channels, while L-, and P/Q-type channels represented a smaller fraction. Mibefradil caused a rapid and reversible dose-dependent block of inward Ca2+ channel currents. Inhibition was nearly complete at 10 microM, suggesting mibefradil blockade of all subclasses of Ca2+ channels. The IC50 was approximately 1.4 microM on currents measured at 0 mV, from a holding potential of -90 mV. Inhibition of LVA Ca2+ current occurred over the same contraction range. Slow tail currents induced by the dihydropyridine agonist Bay K 8644 were also blocked by mibefradil, although with a slightly lower potency (IC50 = 3.4 microM). These broad inhibitory effects of mibefradil on Ca2+ influx were also supported by the strong inhibition of depolarization-induced intracellular calcium transients, measured from Indo-1 loaded motoneurones imaged with confocal microscopy. We conclude that mibefradil has potent blocking effects on Ca2+ channels in mammalian motoneurones. We hypothesize that therapeutic and pharmacological effects of mibefradil may involve actions on Ca2+ channels other than type T.

Abnormal intracellular ca(2+)homeostasis and disease.

A whole range of cell functions are regulated by the free cytosolic Ca(2+)concentration. Activator Ca(2+)from the extracellular space enters the cell through various types of Ca(2+)channels and sometimes the Na(+)/Ca(2+)-exchanger, and is actively extruded from the cell by Ca(2+)pumps and Na(+)/Ca(2+)-exchangers. Activator Ca(2+)can also be released from internal Ca(2+)stores through inositol trisphosphate or ryanodine receptors and is taken up into these organelles by means of Ca(2+)pumps. The resulting Ca(2+)signal is highly organized in space, frequency and amplitude because the localization and the integrated free cytosolic Ca(2+)concentration over time contain specific information. Mutations or functional abnormalities in the various Ca(2+)transporters, which in vitro seem to induce trivial functional alterations, therefore, often lead to a plethora of diseases. Skeletal-muscle pathology can be caused by mutations in ryanodine receptors (malignant hyperthermia, porcine stress syndrome, central-core disease), dihydropyridine receptors (familial hypokalemic periodic paralysis, malignant hyperthermia, muscular dysgenesis) or Ca(2+)pumps (Brody disease). Ca(2+)-pump mutations in cutaneous epidermal keratinocytes and cochlear hair cells lead to, skin diseases (Darier and Hailey-Hailey) and hearing/vestibular problems respectively. Mutated Ca(2+)channels in the photoreceptor plasma membrane cause vision problems. Hemiplegic migraine, spinocerebellar ataxia type-6, one form of episodic ataxia and some forms of epilepsy can be due to mutations in plasma-membrane Ca(2+)channels, while antibodies against these channels play a pathogenic role in all patients with the Lambert-Eaton myasthenic syndrome and may be of significance in sporadic amyotrophic lateral sclerosis. Brain inositol trisphosphate receptors have been hypothesized to contribute to the pathology in opisthotonos mice, manic-depressive illness and perhaps Alzheimer's disease. Various abnormalities in Ca(2+)-handling proteins have been described in heart during aging, hypertrophy, heart failure and during treatment with immunosuppressive drugs and in diabetes mellitus. In some instances, disease-causing mutations or abnormalities provide us with new insights into the cell biology of the various Ca(2+)transporters.

Stimulation and inhibition of pituitary growth hormone release by angiotensin II in vitro.

Rat pituitary cell aggregates cultured in serum-free chemically defined medium, single cells, and hemipituitaries were used in a perifusion system to study the influence of angiotensin II (AII) on GH release. In aggregates the peptide displayed both stimulatory and inhibitory effects on GH release, depending on the hormonal conditions of the culture medium and the age of the animal. When cultured in the absence of glucocorticoid, a modest but statistically significant stimulation was seen in aggregates from immature as well as adult animals. In aggregates from 5-day-old animals, dexamethasone (DEX) strongly enhanced the GH-releasing activity of AII in a dose-dependent way; in aggregates from 14- and 25-day-old rats, the same pattern was found, although the stimulatory action was weaker than the effect in 5-day-old rats. In aggregates from adult animals, the glucocorticoid established an inhibitory effect of AII on GH release, an effect seen with both low and high concentrations of DEX. These age- and DEX-dependent effects were not found for AII stimulation of PRL release. In the presence of DEX, AII also inhibited GRF-induced GH release in aggregates from adult animals, while it was synergistic with GRF in aggregates from developing animals. The effects of AII on GH release disappeared when aggregates were redispersed into single cells. However, in these single cell preparations AII strongly stimulated PRL release. In hemipituitaries from 1-, 5-, and 14-day-old animals, AII also stimulated GH release, but no effect was seen in hemipituitaries from 25-day-old and adult animals. These data indicate that AII has dual effects on GH release depending on the developmental stage of the animal and the hormonal environment. Furthermore, since no effect of AII was seen after redispersion of aggregates into single cells, both stimulatory and inhibitory effects seem to be based on an intercellular signaling system.

Mutational analysis of the Cu/Zn superoxide dismutase gene in 23 familial and 69 sporadic cases of amyotrophic lateral sclerosis in Belgium.

Amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative disorder caused by degeneration of motor neurons of the spinal cord and brain. The majority of ALS cases are sporadic (SALS). However, in 10-15% of ALS cases the disease is inherited as an autosomal dominant trait (familial ALS or FALS). We used a non-radioactive SSCP method, in combination with solid phase sequencing, to screen the entire SOD1 (Cu/Zn superoxide dismutase) coding region and flanking intronic sequences for mutations. Twenty-three patients from 11 ALS families and 69 SALS patients of Belgian origin were studied. Three different mutations were identified (L38V, D90A and G93C) in seven families. Importantly, the D90A was only found in the heterozygous state. In addition two single base pair variants (IVS1 + 19G > A and AAC139 AAT) were identified in two SALS patients. These results suggest that the SOD1 analysis is useful in FALS but less so in SALS cases. The SSCP analysis has proved fast and reliable for this purpose.

Myasthenic syndrome caused by direct effect of chloroquine on neuromuscular junction.

Chloroquine induced a myasthenic syndrome in a patient taking the drug for presumable reticular erythematous mucinosis. Clinical features and results of single-fiber electromyography were typical for a failure of neuromuscular transmission, while peripheral nerves and muscles were intact on clinical, biochemical, electrophysiologic, and pathologic investigation. The time course of the clinical and electrophysiologic findings during provocation with chloroquine and the absence of autoantibodies indicate that the syndrome was due to a direct effect of the drug on the neuromuscular junction. While not taking chloroquine, the patient showed a decremental response on a modified double-step nerve stimulation test and a mean consecutive difference on single-fiber electromyography that was at the upper limit of normal, indicating a subclinical impairment of neuromuscular transmission. These findings can explain the apparent rarity of the syndrome described, as a direct effect of chloroquine on the neuromuscular junction may only have clinical relevance in patients with a reduced neuromuscular safety factor.

Familial juvenile focal amyotrophy of the upper extremity (Hirayama disease). Superoxide dismutase 1 genotype and activity.

BACKGROUND: Juvenile focal amyotrophy of the arm is an unusual focal motor neuron disease that is rarely familial. Its pathogenesis is unknown. We recently described a family with amyotrophic lateral sclerosis associated with a mutation in the superoxide dismutase 1 (SOD1) gene substituting an aspartate for an alanine (D9OA). One of the carriers of this mutation had focal and nonprogressive amyotrophy of the arm, suggesting that focal amyotrophy might be associated with SOD1 mutations. OBJECTIVES: To describe the phenotype of 2 brothers with juvenile focal amyotrophy of the upper extremity and to characterize their SOD1 genotype and SOD activity. METHODS: Polymerase chain reaction and sequencing of the SOD1 gene and colorimetric measurement of the enzyme activity. RESULTS: We compared the phenotype of our patients to that of 375 patients described in the Western literature. The 5 exons of the SOD1 gene were normal, as was the SOD activity in red blood cells.

Diffusion-weighted MRI in sporadic Creutzfeldt-Jakob disease.

Diffusion-weighted MRI (DWI) was used in three patients with autopsy-proven sporadic Creutzfeldt-Jakob disease (CJD) to provide a rapid noninvasive way to make this sometimes confusing diagnosis. DWI prompted the diagnosis of CJD at an early stage and appears to be particularly useful for monitoring the progression of the disease. We suggest that patients with suspected CJD and no abnormalities on T2- and proton density-weighted images may have cortical involvement on DWI.

D90A heterozygosity in the SOD1 gene is associated with familial and apparently sporadic amyotrophic lateral sclerosis.

All mutations in the SOD1 gene associated with familial ALS behave as dominant traits. One mutation, however, giving rise to an aspartic acid to alanine substitution in codon 90 (D90A), was reported only to induce motor neuron disease in homozygous individuals in the Scandinavian population. We describe two families with ALS and one apparently sporadic ALS patient who are heterozygous for the D90A mutation. One patient had the unusual phenotype of focal nonprogressing motor neuron disease.