Pattern and significance of white matter abnormalities in myotonic dystrophy type 1: an MRI study

We reviewed the brain MRI of 66 patients with the adult form of myotonic dystrophy type 1 (DM1) to evaluate the extent and significance of white matter involvement and to look for a pattern of MRI abnormalities suggestive of DM1. White matter lesions (WMLs) and large Virchow Robin spaces (VRSs) were rated by semiquantitative methods and the signal intensity of white matter superior and posterior to the trigones (WMPST) by reference to standard images. Disease duration was correlated positively with WML and negatively with VRS scores. Patients were divided into four groups according to increasing severity of WMPST involvement: group A with mild WMPST hyperintensity, group B with large VRSs and mild or moderate WMPST hyperintensity, group C with moderate WMPST hyperintensity or mild WMPST hyperintensity with small WMLs, group D with severe WMPST hyperintensity or moderate WMPST hyperintensity with small WMLs. Disease duration, muscular impairment, lobar WMLs and brain atrophy significantly increased from groups A and B (not significantly different) to C and from C to D, while convexity VRSs significantly decreased from group B to C and from C to D. Lobar white matter involvement in DM1 seems progressive during the disease and may be characterized initially by large VRSs or mild WMPST hyperintensity, then by small WMLs or moderate WMPST hyperintensity, and finally by more extensive and confluent WMLs or diffuse white matter hyperintensity and by brain atrophy.

Brain MRI features of congenital- and adult-form myotonic dystrophy type 1: case-control study

To compare and characterize the magnetic resonance imaging (MRI) of brain in the congenital and adult form of myotonic dystrophy type 1, we evaluated five patients with congenital dystrophy type 1, 10 age- and 10 disease duration-matched patients with adult-form dystrophy type 1 and 20 age-matched healthy volunteers. The ventricular enlargement was evaluated by the ventricular:brain ratio, the signal intensity of white matter posterosuperior to trigones by reference to standard images and the white matter lesions by a semiquantitative method. In the congenital dystrophy type 1, MRI was characterized by ventriculomegaly and moderate/severe hyperintensity of white matter posterosuperior to trigones, which showed no correlation with the age. MRI in the adult-form dystrophy type 1 was strictly related to disease duration and varied between normal findings, except for temporo-polar white matter lesions, in age-matched patients and ventriculomegaly with white matter hyperintensities in disease duration-matched patients. These results suggest that the origin of MRI abnormalities in myotonic dystrophy type 1 is mainly developmental for the congenital form and mainly degenerative for the adult form.

Early onset autosomal dominant dementia with ataxia, extrapyramidal features, and epilepsy

OBJECTIVE

To perform a clinical and molecular study of a large autosomal dominant family with a complex neurologic syndrome that comprises early-onset dementia, extrapyramidal and cerebellar features, and epilepsy.

BACKGROUND

Early-onset forms of dementia often are caused by genetic factors. Mutations of three different genes-amyloid precursor protein (APP), presenilin 1 (PS-1), presenilin 2 (PS-2)-have been found in early-onset autosomal dominant forms of AD, of the human microtubule associated-protein tau gene (MAPT) in frontotemporal dementia and parkinsonism linked to chromosome 17 (FTDP-17), of the BRI gene in familial British dementia, of the PI12 gene in familial encephalopathy with neuroserpin inclusion bodies. Linkage to chromosome 3 has been found in familial nonspecific dementia (FND) and linkage to chromosome 20 has been found in Huntington disease (HD)-like neurodegenerative disease. Dementia may be a feature of other neurodegenerative diseases such as HD, dentatorubro-pallidoluysian atrophy (DRPLA), diseases caused by mutations of the prion protein gene (PRNP), spinocerebellar ataxias (SCA), and familial parkinsonism.

METHODS

A southern Italian family with autosomal dominant dementia-plus was observed. The family includes 57 individuals in 5 generations (14 affected, 7 personally observed). The authors performed linkage analysis to APP, PS-1, PS-2, FTDP-17, BRI, PI12, FND, HD-like, SCA4, SCA5, SCA10, SCA11, SCA13, PARK1, PARK2, PARK3 loci; direct mutation analysis of HD, DRPLA, SCA1, SCA2, SCA3, SCA6, SCA7, SCA8, SCA12, and PRNP genes; and sequencing of the PRNP open reading frame.

RESULTS

Linkage to the examined loci was excluded. All of the direct mutation analyses were negative excluding mutations in the examined genes.

CONCLUSIONS

This family has a peculiar phenotype and molecular analyses excluded genes known to cause hereditary dementias.

Dilated Virchow-Robin spaces in myotonic dystrophy: frequency, extent and significance

To study the frequency, extent and significance of dilated Virchow-Robin spaces (VRSs) in dystrophia myotonica (DM), we evaluated the cranial magnetic resonance imaging (MRI) of 41 patients with the adult form of DM and 41 healthy controls. Dilated VRSs and white matter lesions (WMLs) were rated according to semiquantitative methods. Convexity VRSs were more frequent (68 vs. 34%; p < 0.01) and severer (median scores: 4 vs. 0; p < 0.01) in DM patients than in controls, while lenticulostriate VRSs did not show significant differences in frequency (83 vs. 70%; p > 0.05) and severity (median scores: 4 vs. 3; p > 0.05). WMLs were more frequent (66 vs. 22%; p < 0.01) and severer (median scores: 5 vs. 0; p < 0.01) in patients. Disease duration was negatively correlated with convexity VRSs and positively with lobar (centrum semiovale) WML scores. Dilated convexity VRSs might be one of the initial findings in cranial MRI of DM, preceding the appearance of lobar WMLs.

T2 relaxometry of brain in myotonic dystrophy

We investigated the nature and extent of brain involvement in myotonic dystrophy (DM), examining possible T2 relaxation abnormalities in the brain of 20 patients with adult-onset DM and 20 sex- and age-matched normal controls. Brain MRI was performed at 0.5 T, and T2 values were calculated from signal intensity in two echoes. Regions of interest included: frontal, parietal, temporal, occipital and callosal (rostral and splenial) normal-appearing white matter; frontal, occipital, insular and hippocampal cortex; caudate nucleus, putamen, globus pallidus and thalamus. All white-matter and occipital and right frontal cortex regions showed a significantly longer T2 in the patients. Multiple regression analysis, including grey- and white-matter T2 as dependent variables, plus age at onset and at imaging, disease duration, muscular disability, brain atrophy and CTG trinucleotide repeats as independent variables, revealed that only white-matter T2 elongation and disease duration correlated positively. White-matter involvement in DM is more extensive than previously reported by MRI and neuropathological studies and seems to be progressive in the course of disease.

Does abnormal neuronal excitability exist in myotonic dystrophy? I. Effects of the antiarrhythmic drug hydroquinidine on slow saccadic eye movements

The abnormal neuronal excitability hypothesized in myotonic dystrophy (MD) might contribute to psychomotor and behavioral disturbances of MD patients. To gain new insights into the pathophysiology of MD, we determined whether the antiarrhythmic drug hydroquinidine would ameliorate slow saccadic eye movements (SEMs), apathy and hypersomnia in MD patients. SEMs were selected as simple modality for psychomotor investigation. The study was conducted in a randomized, placebo-controlled, double-blind, crossover manner. Ten ambulatory patients without contraindications to hydroquinidine administration were enrolled. Hydroquinidine (450 mg/day) or placebo was given orally for 6 weeks with a washout period of 6 weeks between treatments. SEMs were recorded by electrooculography and analyzed by a computer system. Two patients withdrew in the first week of active treatment because of nausea and epigastralgia. Hydroquinidine significantly increased the normalized peak saccadic velocity and shortened the saccadic reaction time compared to placebo. The drug's effects on apathy and hypersomnia are presented in a companion paper.

Does abnormal neuronal excitability exist in myotonic dystrophy? II. Effects of the antiarrhythmic drug hydroquinidine on apathy and hypersomnia

An abnormal neuronal excitability in myotonic dystrophy (MD) might contribute to psychomotor and behavioral disturbances of MD patients. To gain new insights into the pathophysiology of MD, we determined whether the antiarrhythmic drug hydroquinidine could ameliorate apathy and hypersomnia besides slow saccadic eye movements in these patients. The study was conducted in a randomized, placebo-controlled, double-blind, crossover manner. Ten ambulatory patients without contraindications to hydroquinidine administration were enrolled. Hydroquinidine (450 mg/day) or placebo was given orally for 6 weeks with a washout period of 6 weeks between treatments. Apathy was evaluated by means of the apathy evaluation scale (AES) and hypersomnia by a sleep diary. Two patients withdrew in the first week of active treatment because of nausea and epigastralgia. The drug significantly reduced AES scores and daily sleep time compared to placebo. Thus, hydroquinidine can ameliorate apathy and hypersomnia in MD. However, the possibility of proarrhythmia and the high frequency of cardiac disturbances in MD seriously limit the therapeutic perspective. The effects on eye movements are presented in a companion paper.

Lack of sodium channel mutation in an Italian family with paramyotonia congenita

OBJECTIVE

To conduct the genotype-phenotype correlation in a family in which several individuals share clinical and electrophysiologic features of paramyotonia congenita (PC).

BACKGROUND

PC, hyperkalemic periodic paralysis (HyperPP), and potassium-aggravated myotonias form the group of hereditary sodium channelopathies. Each of these disorders is associated with different point mutations in SCN4A, the gene encoding the alpha-subunit of the adult human skeletal muscle sodium channel. However, in HyperPP families, evidence of a causative gene different from SCN4A has been found.

METHODS

We conducted direct clinical examination, electrophysiologic (EMG/electroneurographic) and cardiologic studies, as well as laboratory screening in several affected and nonaffected members of the family. We performed the genotype-phenotype correlation by microsatellite linkage and cDNA-mutation analyses of the SCN4A gene.

RESULTS

Affected members in this family showed clinical and electrophysiologic features typical of PC. The disease phenotype segregated with the chromosomal region that includes the SCN4A gene. Analysis of the entire cDNA sequence of the SCN4A gene in the index case disclosed a G3826A transition, which results in the Val1276Ile substitution. However, PCR-single-stranded confirmation polymorphism and direct sequencing analysis of the segment coding for Val-1276 on genomic DNA confirmed the G3826A transition in the index case but was negative in 11 affected members of the family; however, neither mutations nor aberrant splicings causative of the PC phenotype in this family were found on SCN4A.

CONCLUSION

The existence of a second gene different from SCN4A that can give rise to a clinical PC phenotype can be speculated upon.

Establishment and characterization of a human neuroectodermal cell line (TB) from a cerebrospinal fluid specimen

We have established a cell line (TB) from a cerebrospinal fluid (CSF) specimen of a patient with a primary leptomeningeal melanomatosis. TB cell line was immunoreactive with the antibodies for low molecular weight neurofilament protein, vimentin, neuron-specific enolase, chromogranin, synaptophysin and HMB-45 (an antibody sensitive and specific for melanoma). When TB cells were transplanted into nude mice, the same immunohistochemical pattern present in cultured cells was found but surprisingly, a positive staining for desmin was observed. Significant amounts of serotonin and its metabolite were detectable. Retinoic acid but not nerve growth factor was able to induce differentiation towards a neuronal phenotype. In summary, TB cells represent primitive neuroectodermal cells having the potential for neuronal, myoblastic and possibly melanoblastic differentiation.

Late appearance of acanthocytes during the course of chorea-acanthocytosis

A case of chorea-acanthocytosis (CA) syndrome is described. The presence of acanthocytes has usually been considered an important diagnostic marker of CA. However, it is not specific and other neurological diseases have to be considered. In the present report we rule out other diagnostic possibilities and show that the acanthocytes in the peripheral blood smears can appear even later during the course of the disease.

Case-control study of risk factors of Creutzfeldt-Jakob disease in Europe during 1993-95. European Union (EU) Collaborative Study Group of Creutzfeldt-Jakob disease (CJD)

BACKGROUND

Creutzfeldt-Jakob disease (CJD) is a transmissible spongiform encephalopathy. Genetic and iatrogenic forms have been recognised but most are sporadic and of unknown cause. We have studied risk factors for CJD as part of the 1993-95 European Union collaborative studies of CJD in Europe.

METHODS

The 405 patients with definite or probable CJD who took part in our study had taken part in population-based studies done between 1993 and 1995 in Belgium, France, Germany, Italy, the Netherlands, and the UK. Data on putative risk factors from these patients were compared with data from 405 controls.

FINDINGS

We found evidence for familial aggregation of CJD with dementia due to causes other than CJD (relative risk [RR] 2.26, 95% CI 1.31-3.90). No significant increased risk of CJD in relation to a history of surgery and blood transfusion was shown. There was no evidence for an association between the risk of CJD and the consumption of beef, veal, lamb, cheese, or milk. No association was found with occupational exposure to animals or leather. The few positive findings of the study include increased risk in relation to consumption of raw meat (RR 1.63 [95% CI 1.18-2.23]) and brain (1.68 [1.18-2.39]), frequent exposure to leather products (1.94 [1.13-3.33]), and exposure to fertiliser consisting of hoofs and horns (2.32 [1.38-2.91]). Additional analyses, for example stratification by country and of exposures pre-1985 and post-1985, suggest that these results should be interpreted with great caution.

INTERPRETATION

Within the limits of the retrospective design of the study, our findings suggest that genetic factors other than the known CJD mutations may play an important part in CJD. Iatrogenic transmission of disease seems rare in this large population-based sample of patients with CJD. There is little evidence for an association between the risk of CJD and either animal exposure, or consumption of processed bovine meat or milk products for the period studied.

Relative sparing of extraocular muscles in myotonic dystrophy: an electrooculographic study

We studied 40 patients with myotonic dystrophy (MD) to investigate whether saccadic eye movement (SEM) abnormalities have a central or peripheral origin. SEMs were recorded by electrooculography and analyzed by a computer system. Six patients were followed up to 2-7 years. Slow SEMs were present in 70% of patients, while saccadic latency and accuracy were within normal ranges. Peak saccadic velocity (PSV) did not correlate with disease duration and muscular disability, and showed a significant reduction only in 1 patient during the follow-up. Muscular disability correlated significantly with age and disease duration and worsened in 4 patients over time. The doll's head maneuver elicited vestibular compensatory eye movements with high velocities. These findings suggest that the extraocular muscles are at least partially spared in MD and that supranuclear structures, most likely the burst cells in brainstem reticular formation, may contribute to the slowing of SEMs.

Clinical genetic analysis of Parkinson's disease in the Contursi kindred

We performed a clinical genetic analysis of a kindred originating in the town of Contursi in Salerno province, Italy, in which 60 individuals in 5 generations are known to have had Parkinson's disease (PD). Two previously reported autopsy cases showed typical PD with Lewy bodies. The inheritance pattern is apparently autosomally dominant with a segregation ratio of 40.1% for kindred members aged 50 years and older. The mean age at PD onset is 45.6 years (standard deviation, 13.48; range, 20-85) with a mean course to death of 9.2 years (standard deviation, 4.87; range, 2-20). Otherwise, clinical characteristics of PD in the kindred, including variance in onset age and incidence of tremor and levodopa responsiveness, are similar to those of PD in the community. The presence of tremor tended to be concordant in affected parent-child pairs, but there was no parent-child correlation for age at onset or intrasibship clustering of tremor or onset age. A suggestion of anticipation disappeared after adjustment for age-related ascertainment bias. The findings show that a presumably single mutation can produce a heterogeneous PD phenotype, even among siblings. This is consistent with the hypothesis that PD in the community may in fact be caused by such a mutation, but one producing a lower penetrance and older age at onset than those in this kindred.

Quantified-EEG in normal aging and dementias

The value of quantitative electroencephalography (q-EEG) in the differential diagnosis of multi-infarct dementia (MID) and dementia of Alzheimer's type (DAT) is controversial. To evaluate the possible diagnostic role of q-EEG in these two conditions we studied 18 healthy adults, 16 healthy elderly (HE), 29 DAT patients and 45 MID patients. MID patients showed a significant increase of delta activity on the occipital regions, a significant widespread increase of theta activity, a significant widespread decrease of alpha activity. DAT patients showed a significant widespread increase of delta and theta activity, a significant widespread decrease of alpha activity. Spectral profile analysis showed an asymptotic exponential peak frequency at 4.33 HZ, and the disappearance of dominant activity in DAT patients; a 1 Hz decrease of peak frequency with a preserved normal profile in MID patients. We conclude that q-EEG is a useful ancillary test to differentiate MID from DAT.

Central action of cinnarizine and flunarizine: a saccadic eye movement study

The mechanism of action of flunarizine (FZ) and cinnarizine (CZ) on the CNS is not fully understood. Computer analysis of saccadic eye movements (SEM) provides a sensitive and objective method for evaluating drug effect on the function of specific brain structures. This study aimed to assess the effect of a single oral dose of FZ (20 mg) and CZ (150 mg) on CNS function by means of computer analysis of SEM. Ten healthy volunteers were studied according to a double-blind, cross-over, placebo-controlled design. Peak saccadic velocity (PSV), which is related to the function of a specific group of burst neurons located in the brain stem, was significantly reduced by FZ. No significant effect of FZ on saccade accuracy (SA) and saccade latency (SL) was found. CZ did not produce significant effects on SEM, but a trend to decrease PSV. The possibility that a FZ central effect may be related to a stabilizing action on burst activity of neurons is discussed.

Familial amyloidotic polyneuropathy: description of an Italian kindred

Familial amyloidotic polyneuropathy (FAP) is a heterogeneous group of genetic disorders characterized by progressive systemic deposition of extracellular amyloid fibrils, mainly affecting the peripheral nervous system (PNS). These disorders, inherited as an autosomal dominant trait, have frequently been described in various ethnic groups, but have rarely been reported in Italy. A 42 year-old man came to our observation for loss of pain and temperature sense in his legs. Clinical and laboratory data pointed to an amyloidotic polyneuropathy. This led us to discover a large italian kindred in which 19 members were affected by FAP. The diagnosis, established in 8 members on the clinical and laboratory findings, was ana-catamnestic in other 11. In this kindred the onset of the disease ranges from 35 to 50 years of age and the course is progressive and often fatal. The early symptoms are mainly related to autonomic disturbances and to peripheral neuropathy. Cardiac and renal involvement occurs frequently and may be life-threatening.

Possible involvement of the base exchange enzymes in the phospholipid metabolism in LAN-2 cells

The incorporation of [14C] choline, [14C] ethanolamine, and [14C] serine by LAN-2 cells into their corresponding phospholipids was investigated in the presence or absence of TPA. The presence of TPA increased the amount of radioactivity incorporated into the phospholipids with a corresponding decrease in the amount of radioactivity in the cytosolic compartment compared to control cultures. There were no differences between TPA-exposed and control cells in the distribution of radioactivity in free choline, phosphorylcholine or CDP-choline of [14C] choline labeled cells. This indicates that the increased lipid labeling was not accompanied by enhanced labeling of the intermediates of the de novo pathway. These results suggest that a choline base exchange enzyme was stimulated in TPA exposed cells. In addition, the enhanced incorporation of serine by TPA into its corresponding phospholipid implies the stimulation of the serine base exchange enzyme which is responsible for phosphatidylserine synthesis in mammals. These observations suggest a

Pineal cysts: an incidental MRI finding?

The incidence of pineal cysts (PC) in "standard" MRI was reviewed. Seven cases of PC were found from 400 consecutive MRI examinations. PC did not produce clinically relevant symptoms in any of the patients. Our data, as well as those emerging from a critical review of the literature, suggest that PC are often asymptomatic and represent an incidental MRI finding.

Acute effect of flunarizine on saccadic eye movements

It has been postulated that flunarizine (FNZ) acts on the brain through a stabilizing effect on membrane electrical activity of neurones. It has been also suggested that neurogenic events characterized by an increased tendency of nerve cells to fire, could be involved in the pathogenesis of migraine and epilepsy. The study was aimed to assess the effect of a single oral dose of FNZ (20 mg) on CNS specific functions by means of computer analysis of saccadic eye movements. The study was performed on six healthy volunteers according to a double-blind, cross-over, placebo controlled design. FNZ produced a significant reduction only of peak saccadic velocity, thus suggesting a rather specific and selective effect on the burst cells of the para-median pontine reticular formation.