[Movement disorders]

Thanks to the application of modern techniques such as next-generation sequencing in the study of apparently non-inherited encephalopathies it has become possible to describe de novo pathogenic mutations in unsuspected genes and to define the phenotypes of these mutations. Interestingly, in most cases, their clinical signs and symptoms show a spectrum in which epileptic encephalopathy, neurodevelopmental disorder and hyperkinetic abnormal movement disorders overlap. Their pathophysiology is located in synapses (synaptopathies). This article offers a brief summary of these disorders and also includes a simple note, in honour of Dr Natalio Fejerman (1934-2018), on the so-called «benign polymorphic disorder of infancy».

A systematic review on the diagnosis and treatment of primary (idiopathic) dystonia and dystonia plus syndromes: report of an EFNS/MDS-ES Task Force

To review the literature on primary dystonia and dystonia plus and to provide evidence-based recommendations. Primary dystonia and dystonia plus are chronic and often disabling conditions with a widespread spectrum mainly in young people. Computerized MEDLINE and EMBASE literature reviews (1966-1967 February 2005) were conducted. The Cochrane Library was searched for relevant citations. Diagnosis and classification of dystonia are highly relevant for providing appropriate management and prognostic information, and genetic counselling. Expert observation is suggested. DYT-1 gene testing in conjunction with genetic counselling is recommended for patients with primary dystonia with onset before age 30 years and in those with an affected relative with early onset. Positive genetic testing for dystonia (e.g. DYT-1) is not sufficient to make diagnosis of dystonia. Individuals with myoclonus should be tested for the epsilon-sarcoglycan gene (DYT-11). A levodopa trial is warranted in every patient with early onset dystonia without an alternative diagnosis. Brain imaging is not routinely required when there is a confident diagnosis of primary dystonia in adult patients, whereas it is necessary in the paediatric population. Botulinum toxin (BoNT) type A (or type B if there is resistance to type A) can be regarded as first line treatment for primary cranial (excluding oromandibular) or cervical dystonia and can be effective in writing dystonia. Actual evidence is lacking on direct comparison of the clinical efficacy and safety of BoNT-A vs. BoNT-B. Pallidal deep brain stimulation (DBS) is considered a good option, particularly for generalized or cervical dystonia, after medication or BoNT have failed to provide adequate improvement. Selective peripheral denervation is a safe procedure that is indicated exclusively in cervical dystonia. Intrathecal baclofen can be indicated in patients where secondary dystonia is combined with spasticity. The absolute and comparative efficacy and tolerability of drugs in dystonia, including anticholinergic and antidopaminergic drugs, is poorly documented and no evidence-based recommendations can be made to guide prescribing.

GAMT deficiency: Features, treatment, and outcome in an inborn error of creatine synthesis

BACKGROUND

Guanidinoactetate methyltransferase (GAMT) deficiency is an autosomal recessive disorder of creatine synthesis. The authors analyzed clinical, biochemical, and molecular findings in 27 patients.

METHODS

The authors collected data from questionnaires and literature reports. A score including degree of intellectual disability, epileptic seizures, and movement disorder was developed and used to classify clinical phenotype as severe, moderate, or mild. Score and biochemical data were assessed before and during treatment with oral creatine substitution alone or with additional dietary arginine restriction and ornithine supplementation.

RESULTS

Intellectual disability, epileptic seizures, guanidinoacetate accumulation in body fluids, and deficiency of brain creatine were common in all 27 patients. Twelve patients had severe, 12 patients had moderate, and three patients had mild clinical phenotype. Twenty-one of 27 (78%) patients had severe intellectual disability (estimated IQ 20 to 34). There was no obvious correlation between severity of the clinical phenotype, guanidinoacetate accumulation in body fluids, and GAMT mutations. Treatment resulted in almost normalized cerebral creatine levels, reduced guanidinoacetate accumulation, and in improvement of epilepsy and movement disorder, whereas the degree of intellectual disability remained unchanged.

CONCLUSION

Guanidinoactetate methyltransferase deficiency should be considered in patients with unexplained intellectual disability, and urinary guanidinoacetate should be determined as an initial diagnostic approach.

Intracellular levels of the LIS1 protein correlate with clinical and neuroradiological findings in patients with classical lissencephaly

We report on the genotype-phenotype correlation in 7 patients with classical lissencephaly carrying a heterozygous subtle mutation in the LIS1 gene. Six patients, showed a mutation predicted to encode for a truncated protein, and one mutation altered a splicing site, resulting in skipping of exon 4. Western blot analysis performed on the lymphoblastoid cell line of 2 patients bearing truncating mutations indicated that the mutated allele did not produce a detectable amount of the LIS1 protein; whereas the analysis performed on the fibroblasts from the patient with a splice-site mutation was suggestive of partial protein synthesis from the mutated allele. Although clinical and magnetic resonance imaging findings of patients with truncating mutations did not differ from those observed in patients with a heterozygous deletion, the patient bearing the exon-skipping mutation had less severe clinical and brain involvement. Our data suggest that truncating mutations in the LIS1 gene are relatively common among patients with classical lissencephaly not bearing a heterozygous deletion at 17p13.3, and strengthen the relevance of correct intracellular dosage of the LIS1 protein in the neuronal migration process.

Acute necrotizing encephalopathy of childhood (infantile bilateral thalamic necrosis): two non-Japanese cases

This report describes two Spanish cases of acute necrotizing encephalopathy of childhood, a rare disease first described in Japan by Mizuguchi and colleagues. Similar cases have been reported from Taiwan and other countries of the Far East. Two cases have been reported from the UK and one from the USA. The disease affects young children and is characterized by acute encephalopathy after a viral illness, with seizures and decreased levels of consciousness. The hallmark of the disease is diffuse and symmetrical CNS lesions of both thalami, internal capsules, upper brainstem tegmentum, and cerebral white matter. The aetiology is unknown but an infectious or parainfectious process seems likely. Because of the predominant involvement of the thalami, we propose the term 'infantile bilateral thalamic necrosis', a more specific term and one which distinguishes the entity from other basal ganglia diseases in childhood.

New 2-[(5-methoxy-1-methylindolyl)]-alkylamine derivatives: the effect of branching and elongation of the side chain on MAO inhibition

A novel series of previously synthesised 2-[(5-methoxy-1-methylindolyl)]alkylamine derivatives were irreversible and time-dependent mechanism-based inhibitors of MAO. The effect of branching and elongation of the side chain was evaluated on the inhibitory potency towards MAO-A and MAO-B activities. The KI of the reversible step and the kinact of the irreversible one were determined in each case. The results obtained lead to the conclusion that neither the elongation nor the branching of the side chain improve the potency of the compounds as MAO inhibitors.

Transient movement disorders in children

Transient movement disorders are quite common in pediatrc practice, occurring mainly in infants. They are underdiagnosed but represent about 20% of cases of movement disorders (tics excluded) seen in a neuropaediatric department. Dystonia, tremor and myoclonus are the most common. Transient idiopathic dystonia of infancy is quite common, and the diagnosis can be suspected on clinical examination. Knowledge of these disorders avoids not only unnecessary tests and treatment, but also familial anxiety.

Kinetic studies of N-allenic analogues of tryptamine as monoamine oxidase inhibitors

A series of N-allenic analogues of tryptamine in which the side chain is located at the 2 position of the indole ring, but which differed in the ring and side-chain nitrogen substituents, were assayed kinetically as MAO A and MAO B inhibitors. All the compounds studied were mechanism-based inhibitors. The kinetic constants of each inhibition step Ki and ki, were determined for both MAO A and B. The data obtained indicated that these allenic derivatives show a greater selectivity and potency towards MAO A as inhibitors than the corresponding acetylenic derivatives.

Interactions of monoamine oxidase inhibitors, N-acetylenic analogues of tryptamine, with rat liver microsomal cytochrome P450

Interactions between some novel and potent monoamine oxidase inhibitors (MAOIs), acetylenic analogues of tryptamine, and rat liver microsomal cytochrome P450 (P450) as evidenced by visible spectra analysis were analysed. Compounds with a secondary aliphatic amine moiety throughout induced type II difference spectra and exhibited the highest affinity for P450, whereas tertiary amines induced type I spectral changes and showed diminished affinity. P450 dependent aniline hydroxylase activity was inhibited by all compounds in an irreversible time-dependent manner. Only tertiary aliphatic amines constituted the substrate for P450-dependent N-demethylase activity, with comparable kinetic parameters. The N-demethylated metabolites were identified by thin-layer chromatography and mass-spectrometric analyses. These findings describe the role of P450-dependent microsomal mono-oxygenase systems in the metabolism of some MAOI acetylenic tryptamine derivatives and the possible hepatic contribution to adverse interactions between MAOIs, endobiotics and sympathomimetic compounds.

The effect of side chain substitution at positions 2 and 3 of the heterocyclic ring of N-acetylenic analogues of tryptamine as monoamine oxidase inhibitors

N-Acetylenic analogues of tryptamine in which the side chain is located at position 2 of the indole ring are compared with those in which the side chain is located at position 3, in terms of their actions as inhibitors of monoamine oxidases A and B. IC50 values at 0 and 30 min of pre-incubation were determined. Time-dependence and irreversible inhibition confirmed that all of them behave as mechanism-based inhibitors. The kinetic constants of each inhibition step were determined for both monoamine oxidase forms and compared between them. In all cases the first-order rate constants for the covalent adduct formation were similar to inhibitor selectivity which is derived solely from differences in affinities for non-covalent binding to the A and B enzymes. Those compounds where the acetylenic side chain was substituted at position 2 of the heterocyclic ring and selective inhibitors of monoamine oxidase A were more potent than those with the side chain in position 3.

Kinetic and inhibition studies on catechol-O-methyltransferase affinity labelling by N-(3,4-dihydroxyphenyl)maleimide

Initial velocity and product inhibition studies have been performed on soluble catechol-O-methyltransferase which has been partially purified from pig liver. The results are consistent with an ordered reaction mechanism, in which S-adenosyl-L-methionine (AdoMet) is the leading substrate. The enzyme is irreversibly inhibited by maleimide derivatives in a biphasic manner, which suggests a differential reaction with two thiol groups. N-(3,4-Dihydroxyphenyl)maleimide, which has a reactive moiety (maleimide ring) and an affinity moiety (catechol ring), acts as an affinity labelling compound on the more reactive SH group; AdoMet and Mg2+ protect against this modification. Total protection of this SH group results in a pseudo-first-order inhibition of the enzyme, with the apparent rate constant being proportional to the inhibitor concentration. All the other maleimide derivatives studied inhibited the enzyme by reacting with one of the two SH groups in a non-specific manner. The reaction of the other, more reactive, SH group was either specific (active-site-directed) or non-specific, depending on the substituent present in the affinity moiety and also on the length of an intermediate chain of methylene groups present between this moiety and the reactive maleimide ring. In the presence of both AdoMet and Mg2+, 3,5-dinitrocatechol, a reversible inhibitor of the enzyme which is competitive with respect to the catechol substrate, protects the enzyme from inactivation by any of the maleimide derivatives. The adducts of these maleimide derivatives formed with dithiothreitol inhibit the enzyme reversibly, showing inhibition patterns that are consistent with the mechanism deduced from the initial velocity and product inhibition studies.

New 5H-pyridazino[4,5-b]indole derivatives. Synthesis and studies as inhibitors of blood platelet aggregation and inotropics

Some fused 5H-pyridazino[4,5-b]indoles (7-10), substituted in positions 1 and 4 by hydrazine and/or amino groups, have been synthesized. These new compounds present a planar topography, a dipole with an adjacent acidic proton, and a basic hydrogen-acceptor site opposite the dipole. These compounds have some resemblance to carbazeram and other pyridazino agents with cardiotonic activity. Some of the new compounds here described possess inotropic activity (Table I and II), with a complementary effect as inhibitors of platelet aggregation (Table III and IV). 1-Hydrazino-4-(3,5-dimethyl)-1-pyrazolyl-5H-pyridazino[4,5-b ]indole hydrochloride (7a.HCl) is the first compound described in the literature with activities as inhibitor of PDE-IV and as selective inhibitor of TXA2 synthetase (Table V).

New 5H-[1,3]thiazolo[3,2-a]pyrido[3,2-e]pyrimidine derivatives as diuretics

New 5H-[1,3]thiazolo[3,2-a]pyrido[3,2-e]pyrimidines 1 and 6,10-dihydro-5H-pyrido[3',2':5,6]pyrimido[2,1-c] [1,2,4]triazines 4 with 5-one, 5-thione or 5-hydrazono substituents and in some cases 1,2,3,4 or 8,9 hydrogenated are synthetized. The diuretic, natriuretic and kaliuretic activities of these compounds in Wistar rats at a dose of 24 mg/kg were estimated. A series of 24 possible derivatives of 1 and 4 possessing diuretic and saliuretic activities are investigated for structure-activity relationships in light of Fujita-Ban model. The Fujita-Ban group contributions have been calculated for different structural variations on the parent ring 1a. It is observed that the hydrogenation of pyridine, [1,3]thiazole or [1,2,4]triazine rings on 1 or 4 decrease the diuretic and saliuretic activities.

Inhibition of MAO by substituted tryptamine analogues

Three different acetylenic analogues of tryptamine, in which the side chain is attached at the 2 position of the heterocyclic ring, were studied as inhibitors of MAO-A and MAO-B. IC50 values were determined after 30 min preincubation of the enzyme and inhibitor, at 37 degrees C before assay. Irreversibility and time-dependence of the inhibition were also established in each case. The kinetic parameters defining non-covalent complex formation and covalent adduct formation were calculated for the mechanism-based inhibition of both MAO-A and MAO-B by these compounds.

CT appearance of low attenuation areas in basal ganglia in childhood: report of 23 cases

Low attenuation areas were seen at CT in the basal ganglia of 23 patients aged less than 15 years. The relationship between CT images and pathological findings is investigated and the differential diagnosis is made.

Dystonia as a presenting sign of subacute necrotising encephalomyelopathy in infancy

A case of subacute necrotising encephalomyelopathy is reported with such note worthy features as early onset, dystonic manifestations and the presence of low attenuation areas in the basal ganglia on computerised tomography of the brain. Laboratory findings were normal and the diagnosis was confirmed at postmortem examination.

[Episodes of apnea in an infant: unusual forms of epileptic seizures]

The authors report the observation of an infant who begins at the age of 7 months to present episodes of epileptic apnea with cyanosis, lost of consciousness, hypotony and sometimes ocular revulsion and distal myoclonia. From their onset there are several a day, more frequent during sleep than when awake. From the EEG point of view they are characterized by a 5-7 c/sec large and diffuse rhythm. The infant also presents epileptic myoclonias, tonic and partial seizures. She has a very slight evolutive encephalopathy, disclosed at the age of 4 months by a psychomotor retardation. No etiology has been proved. The CT scan shows during the evolution a cortico-subcortical atrophy. Every type of seizure was very resistant to different treatments. The apneas disappeared after ACTH therapy. The authors demonstrate the epileptic nature of these apneas which are very rarely observed after the neonatal period.

Fine structure based on the Golgi method of the abnormal cortex and heterotopic nodules in pachygyria

The structure of the four-layer abnormal cerebral cortex and of the heterotopic cerebral nodules in pachygyria has been studied by means of the Golgi method. The external cellular layer is formed by neurons closely mimicking, in morphology and distribution, those observed in layers V-VI of the normal cortex, although major abnormalities in orientation of pyramidal cells are a prominent abnormal feature. The internal cortical cellular layer is composed of several neuron types in which no distinctive layered organization can be detected. Heterotopic cerebral nodules are formed by neurons of the cortical types with random orientation of their cellular processes. Some extrinsic axons have been demonstrated, thus suggesting lack of isolation of heterotopic nodules.

[Electroencephalographic morphology of seizures in full-term newborn infants]

e studied the morphology of the electrical discharges of 63 newborns who presented an electrical or electro-clinical status of known aetiology. The seizures have been classified as: discharges of beta, alpha, theta and delta frequencies; discharges of diphasic spikes; discharges of "saw waves"; positive spikes or slow waves, burst-suppressions and extremely polymorph discharges. We confirm the existing opinion in the current literature that the discharges are really changeable and polymorphic, are modified during seizure and vary in morphology, voltage, frequency and polarity. A typical or characteristic pattern of the seizures of newborn does not exist although theta and delta frequencies are predominant. A correlation between voltage, frequency and duration of the electrical discharge seems to exist; the higher the frequency of the electrical discharge, the lower is its voltage and its duration and vice versa. The cortical immaturity of the newborn plays an important role in the morphological changes of the electrical discharges.

Chronic progressive encephalitis in children with x-linked hypogammaglobulinemia

This report is on six cases of a chronic relentlessly progressive encephalitis occurring in boys with congenital hypogammaglobulinemia presumably of the x-linked type, which are thought to represent a separate neurological entity. Intellectual deterioration, dysarthria, spasticity, ataxia, optic atrophy and an increase of lymphocytes in the cerebrospinal fluid, were the main clinical signs. The pathological picture was that of a viral encephalitis, but all virological investigations on brain biopsies and CSF were negative. The significance of intra-cisternal tubuloreticular inclusions in brain endothelial cells, similarities with chronic rubella encephalitis, and the role of the immunological deficiency are discussed. Sofar, the cause of this new type of encephalitis remains obscure.

Uncommon case of type II glycogenosis

The authors report an uncommon case of type II glycogenosis. An 8-year-old boy developed a slow progressive myopathy. Biopsy of skeletal muscle showed scarce lesions under the optic microscope but in 50% of the fibers the presence of vacuoles filled with glycogen under the electron microscope. Ultrastructural analysis of fibroblasts in culture showed numerous vacuoles filled with glycogen, characteristic of type II glycogenosis. Enzymatic analysis revealed that acid-alpha-glucosidase activity was normal in muscle tissues but deeply deficient in leukocytes and fibroblasts in culture. This is, as far as we know, the first case with such a discrepancy in the distribution of the enzymatic activity, and it underlines the necessity of investigating several tissues in atypical cases.

"Moya-moya' disease caused by cranial trauma

A case of "moya-moya" disease of a 12-year-old boy is reported. The clinical history started at 3 years 2 months after cranial trauma. The patient developed mental retardation, hemiparesis and seizures.

[Lissencephaly: agyria. A study using the Golgi technic]

A case of lissencephaly (agyria) is reported in which the Golgi stain was used to study the fronto-parietal cortex. The external cellular layer, the so-called true cortex, was shown to be made up of neurons from the 5th and 6th layers of the normal cortex. The neurons in the much less cellular layer were shown to be large pyramidal cells with well-developed dendritic branching and spines. The deeper cellular layer was a neuronal pool without well-defined layering. All the neural forms from the normal cortex were represented. In this layer the inner neurons showed a less advanced stage of development than did those in the outer groups. In the external cellular layer there was a disorganization of neuronal disposition as well. Otherwise typical large and medium-sized pyramidal cells from the outer third showed apical dendrites directed towards deeper structures, and the basal dendrites ran through the marginal layer. Neurons with doulbe dendritic branching and fusiform neurons were present in an abnormal rotated position. In both cases, the axons always showed a descending direction. These findings add to existing knowledge concerning the anatomy of the lissencephalic cortex, although the exact interpretation of the abnormalities found in the external cellular layer remains speculative.