[Psychiatric disorders in adult form of Niemann-Pick disease type C]

INTRODUCTION

Niemann-Pick type C disease (NPC) is a rare genetic disease with an extremely heterogeneous clinical presentation. The adult form of this disease is usually expressed with neurological symptoms; however, non-specific psychiatric disorders are often associated. This article presents a retrospective study on a cohort of NPC patients diagnosed in France with the objectives of researching the presence of psychiatric disorders and qualifying these disorders.

METHODS

After carrying out a research within hospital records, a questionnaire was sent to patients or their relatives and their doctors.

RESULTS

The cohort was made up of 22 patients. Fifty-two questionnaires were sent to 47 different doctors. We received 67% of answers from the doctors, with 42% of positive answers. The answer rate of the families was 27%. Among the 22 patients, we found the presence of psychiatric disorders in 86% of cases. Seventy-three percent of the patients presented behavior disorders. Among them, 27% exhibited psychomotor excitation or agitation, 23% aggressiveness, 18% intolerance to frustration, 27% sleep disorders and 23% apathy, listlessness and/or clinophilia. Fifty-five percent of patients presented psychotic symptoms, with 45% with delusions and 36% with hallucinations. Seventy-seven percent of patients presented with mood disorders: 36% suffered from depression and 27% from emotional lability or mood swings. Of the 22 patients, a diagnosis of psychiatric disease was made in 50% of cases. The main diagnoses were schizophrenia (27%) and depression (23%). The other diagnoses identified were acute delirium, dysthymia, infantile psychosis, intellectual disharmonic disability and personality disorder. The average age of emergence of the troubles was 17.1 years old for neurological symptoms and 20.9 years old for psychiatric symptoms. The median age was 18 years old for neurological symptoms and 20 years old for psychiatric ones. In 45% of cases, psychiatric occurred after neurological symptoms; in 27%, they occurred before and they were concomitant in 9%. In 50% of cases, psychiatric symptoms existed before the early diagnosis of NPC; in 9%, they occurred after and in 5%, they occurred during the diagnostic process. Fifty-five percent of the patients were followed by a psychiatrist, 50% of patients had been hospitalized at least once in a psychiatric department. Fifty-five percent of the patients received neuroleptics or antipsychotics, 41% received antidepressants, 41% received mood stabilizers or anticonvulsants, 45% received anxiolytics and 23% hypnotics.

DISCUSSION

Whilst a small cohort, the low incidence of NPC (1/120,000 to 1/150,000) and the scale of a single-center study make the findings important. In our cohort, we found psychiatric disorders in most of the patients. The symptoms were varied and non-specific, and mainly found in late-onset forms of the disease. This incidence of disorder is much higher than the literature suggests, generally describing psychiatric disorders in approximately one third of NPC adult form. On the other hand, our results on schizophrenia are consistent with the updated recommendations for the diagnosis and management of NPC. According to our results, a retrospective study to develop a suspicion index to aid diagnosis of NPC suggests that psychotic symptoms are underestimated in this disease. In our cohort, we also found a significant rate of psychiatric hospitalizations and psychotropic drugs prescription that had not been previously described in the international literature. We did not have sufficient data on the effectiveness of symptomatic treatment in NPC; the literature was contradictory. It should be noted that despite the high rate of psychiatric patients in our cohort, only half of patients consulted a psychiatrist and a few of them have regular follow-up. To conclude, our study is in line with the current literature that suggests an under-estimation of psychiatric disorders in NPC, but also a likely under-diagnosis of NPC in psychiatric departments. All this data encourage us to keep alerting psychiatrists to identifying this disease in order to promote early and optimal care.

[Inborn errors of metabolism in adult neurology]

Inborn errors of metabolism (IEM) are caused by mutations in genes coding for enzymes and other proteins involved in cell metabolism. Many IEM can be treated effectively. Although IEM have usually been considered pediatric diseases, they can present at any age, mostly with neurological and psychiatric symptoms, and therefore constitute an integral subspeciality of neurology. However, although they are increasingly being recognized, IEM remain rare, and the care for patients should be optimized in specialized reference centers. Since the number of different diseases is very large, the diagnostic approach needs to be rigorous, starting at the clinics and calling upon the additional help of neuroradiology, biochemistry and molecular biology. In practice, it is important for the neurologist to recognize: (1) when to start suspecting an IEM; and (2) how to correlate a given clinical presentation with one of the five major groups of diseases affecting the nervous system. These five groups may be classified as: (a) energy metabolism disorders such as respiratory chain disorders, pyruvate dehydrogenase deficiency, GLUT1 deficiency, fatty-acid β-oxidation defects, and disorders involving key cofactors such as electron transfer flavoprotein, thiamine, biotin, riboflavin, vitamin E and coenzyme Q10; (b) intoxication syndromes such as porphyrias, urea-cycle defects, homocystinurias, organic acidurias and amino acidopathies; (c) lipid-storage disorders such as lysosomal storage disorders (Krabbe disease, metachromatic leukodystrophy, Niemann - Pick disease type C, Fabry disease and Gaucher's disease), peroxisomal disorders (adrenomyeloneuropathy, Refsum disease, disorders of pristanic acid metabolism, peroxisome biogenesis disorders), Tangier disease and cerebrotendinous xanthomatosis; (d) metal-storage diseases such as iron, copper and manganese metabolic disorders; and (e) neurotransmitter metabolism defects, including defects of serotonin, dopamine and glycine metabolism.

Disorders of phospholipids, sphingolipids and fatty acids biosynthesis: toward a new category of inherited metabolic diseases

We wish to delineate a novel, and rapidly expanding, group of inborn errors of metabolism with neurological/muscular presentations: the defects in phospholipids, sphingolipids and long chain fatty acids biosynthesis. At least 14 disorders have been described so far. Clinical presentations are diverse but can be divided into (1) diseases of the central nervous system; (2) peripheral neuropathies; and (3) muscular/cardiac presentations. (1) Leukodystrophy and/or iron deposits in basal ganglia is a common feature of phospholipase A2 deficiency, fatty acid hydroxylase deficiency, and pantothenate kinase-associated neurodegeneration. Infantile epilepsy has been reported in GM3 synthetase deficiency. Spastic quadriplegia with ichthyosis and intellectual disability are the presenting signs of the elongase 4 deficiency and the Sjogren-Larsson syndrome caused by fatty aldehyde dehydrogenase deficiency. Spastic paraplegia and muscle wasting are also seen in patients with mutations in the neuropathy target esterase gene. (2) Peripheral neuropathy is a prominent feature in PHARC syndrome due to α/β-hydrolase 12 deficiency, and in hereditary sensory autonomic neuropathy type I due to serine palmitoyl-CoA transferase deficiency. (3) Muscular/cardiac presentations include recurrent myoglobinuria in phosphatidate phosphatase 1 (Lipin1) deficiency; cardiomyopathy and multivisceral involvement in Barth syndrome secondary to tafazzin mutations; congenital muscular dystrophy due to choline kinase deficiency, Sengers syndrome due to acylglycerol kinase deficiency and Chanarin Dorfman syndrome due to α/β- hydrolase 5 deficiency. These synthesis defects of complex lipid molecules stand at the frontier between classical inborn errors of metabolism and other genetic diseases involving the metabolism of structural proteins.

Natural history of Niemann-Pick disease type C in a multicentre observational retrospective cohort study

Niemann-Pick disease type C (NP-C) is a devastating genetic disorder characterised by progressive neurological deterioration. However, data on the progression of neurological manifestations, particularly across different patient age-of-disease onsets, are limited. This is an observational retrospective cohort study designed to assess the progression of neurological disease in patients with NP-C. Physicians were asked to retrospectively complete a web-based questionnaire for each patient, at diagnosis and at up to three follow-up visits. An NP-C-specific disability scale was used to measure disease progression. The scale comprised four key parameters of neurological disease progression; ambulation, manipulation, language and swallowing. Disease progression was evaluated based on the annual rate of change in each parameter and the composite score using a linear mixed model analysis, and by classifying patients according to the number of worsened parameters during the observation period. Data were collected from 57 patients. The rate of deterioration was similar across the four individual parameters of the disability scale. The mean (95% CI) annual disease progression was +0.12 (0.09, 0.15) units. Among patients with a time interval of at least 1 year between diagnosis and last visit (n=49), 42 (86%) patients had progressed disease and 7 (14%) patients had stable disease. Disease progression was consistently more rapid in patients diagnosed in early childhood, compared with those diagnosed in late childhood, or with juvenile or adult presentation. In conclusion, our findings showed a progression in all four parameters of the disability scale, representing a continuous, unbroken progression of neurological manifestations.

Aseptic meningitis and ischaemic stroke in Fabry disease

BACKGROUND

Fabry disease (OMIM 301 500) is an X-linked lysosomal storage disease. Neurological symptoms in Fabry disease mainly include stroke, acroparesthesia, cranial nerve palsies and autonomic dysfunction. We report on aseptic meningitis in Fabry patients.

METHODS

Clinical analysis, brain magnetic resonance imaging, cerebrospinal fluid analysis, treatment and outcome data were analysed in three cases of meningitis associated with Fabry disease.

FINDINGS

Mean age at meningitis onset was 26.6 (24-28) years. Headache was present in all cases and fever in two cases. Meningitis was always diagnosed before Fabry disease. A familial history of Fabry disease was present in two cases. Non-neurological symptoms caused by Fabry disease were present in all cases. All patients also suffered stroke and sensorineural hearing loss. Cerebrospinal fluid (CSF) analysis showed pleocytosis (mean, 36; range: 8-76 cells/mm(3)) and a high protein level (mean, 63; range, 47-70 mg/dl). C-reactive protein blood levels and erythrocyte sedimentation rate were raised. Diagnosis was assessed by low alpha-galactosidase A dosage and/or gene mutation analysis in all cases. All patients were treated with enzyme replacement therapy (ERT). In two cases, lumbar puncture was repeatedly performed and there was no normalisation of CSF under ERT alone, at 9 and 24 months of follow-up, respectively. One patient who suffered intracranial hypertension was treated efficiently with steroids, associated with azathioprine. The fact that Fabry disease could be an auto-inflammatory disorder is discussed.

INTERPRETATION

Fabry disease may cause aseptic meningitis.

Miglustat in patients with Niemann-Pick disease Type C (NP-C): a multicenter observational retrospective cohort study

Miglustat has been shown to stabilize disease progression in children, juveniles and adults with Niemann-Pick disease type C (NP-C), a rare genetic disorder characterized by progressive neurological deterioration. We report findings from a retrospective observational cohort study assessing the effects of miglustat on neurological disease progression in patients treated in the clinical practice setting. Data from all NP-C patients prescribed miglustat at 25 expert centers were evaluated using a disease disability scale. The scale analyzed four key parameters of neurological disease progression in NP-C (ambulation, manipulation, language, swallowing). Mean individual parameter scores and a composite score were calculated at baseline (time of diagnosis) and up to 4 follow-up visits. Overall, 66 patients were included (mean [SD] age at diagnosis, 9.7 [7.6] years, and at treatment start, 12.8 [9.5] years). The median (range) miglustat exposure was 1.46 (0.05-4.51) years. Mean annual progression was +0.11 score units/year from diagnosis to treatment start, indicating disease progression prior to therapy, and decreasing to -0.01 score units/year from treatment start to last clinic visit, indicating stabilization. Stabilization of neurological disease on miglustat was observed in all age groups, but the magnitude of the effect was greater in patients diagnosed in late childhood and in juveniles and adults. Stabilization of neurological disease was also observed in a subset of 19 patients with extended pre-treatment information. Overall, these data support previous clinical trial findings indicating clinically relevant beneficial effects of miglustat on neurological disease progression in patients with NP-C.

Secondary creatine deficiency in ornithine delta-aminotransferase deficiency

AIMS

Ornithine delta-aminotransferase (OAT) deficiency causes gyrate atrophy (GA) of the retina, as a consequence of high plasma ornithine concentrations. Because creatine synthesis requires the conversion of arginine and glycine into ornithine and guanidinoacetate, high ornithine concentration inhibits this reaction thus causing secondary creatine deficiency. The aim of this study was to evaluate the neuropsychological features and creatine metabolism in patients with GA.

METHODS

The study involved 7 GA patients, aged from 11 to 27 years who underwent neuropsychological evaluation and cerebral proton magnetic resonance spectroscopy (MRS).

RESULTS

Neurocognitive impairment was found in 5/7 patients, including mental retardation (3/7), school failure (1/7), major visuospatial dyspraxia (1/7), aggressive behavior (3/7) and epilepsy (2/7). Two patients had normal neuropsychological evaluation. Cerebral proton magnetic resonance spectroscopy revealed a profound creatine deficiency in all patients. MRS data were confirmed by decreased levels of creatine and/or guanidinoacetate in plasma and urine in all patients.

CONCLUSIONS

In our group of patients with GA, we found a high prevalence of neurological impairment, not reported so far, and possibly related to secondary creatine deficiency and hyperornithinemia. We propose to treat mentally retarded GA patients with high doses of creatine, as it may normalize brain creatine levels and help to reduce ornithine levels.

Cerebellar ataxia with elevated cerebrospinal free sialic acid (CAFSA)

In order to identify new metabolic abnormalities in patients with complex neurodegenerative disorders of unknown aetiology, we performed high resolution in vitro proton nuclear magnetic resonance spectroscopy on patient cerebrospinal fluid (CSF) samples. We identified five adult patients, including two sisters, with significantly elevated free sialic acid in the CSF compared to both the cohort of patients with diseases of unknown aetiology (n = 144; P < 0.001) and a control group of patients with well-defined diseases (n = 91; P < 0.001). All five patients displayed cerebellar ataxia, with peripheral neuropathy and cognitive decline or noteworthy behavioural changes. Cerebral MRI showed mild to moderate cerebellar atrophy (5/5) as well as white matter abnormalities in the cerebellum including the peridentate region (4/5), and at the periventricular level (3/5). Two-dimensional gel analyses revealed significant hyposialylation of transferrin in CSF of all patients compared to age-matched controls (P < 0.001)--a finding not present in the CSF of patients with Salla disease, the most common free sialic acid storage disorder. Free sialic acid content was normal in patients' urine and cultured fibroblasts as were plasma glycosylation patterns of transferrin. Analysis of the ganglioside profile in peripheral nerve biopsies of two out of five patients was also normal. Sequencing of four candidate genes in the free sialic acid biosynthetic pathway did not reveal any mutation. We therefore identified a new free sialic acid syndrome in which cerebellar ataxia is the leading symptom. The term CAFSA is suggested (cerebellar ataxia with free sialic acid).

The adolescent and adult form of cobalamin C disease: clinical and molecular spectrum

BACKGROUND

Cobalamin C disease is the most common inborn error of cobalamin metabolism with an autosomal recessive mode of inheritance and mutations within the MMACHC gene. Clinical features, including systemic, haematological and neurological abnormalities, usually occur in the first year of life. Adolescent and adult onset presentations are rare.

METHODS

We report on the clinical, molecular and imaging features in three patients aged 40, 42 and 42 years at the last follow-up. We examine these cases together with eight previously described cases to determine the clinical and molecular features of the disease in adults.

RESULTS

Mean age at onset of clinical symptoms was 26 years; clinical features included predominant neurological disturbances and thromboembolic complications. White matter abnormalities on brain MRI were sometimes observed. Most patients (eight of nine patients investigated) were compound heterozygotes for the 271dupA mutation and a missense mutation. Intramuscular or intravenous hydroxycobalamin therapy stopped the progression of the disease and resulted in a better clinical outcome and favourable biological status in 7/9 treated cases, while the two untreated patients died quickly.

CONCLUSIONS

As cobalamin C disease and related disorders of homocysteine metabolism are treatable conditions, homocysteinaemia should be included in the investigations of patients with progressive neurological deterioration, unexplained psychiatric disturbances or recurrent thromboembolic events.

Leukoencephalopathies associated with inborn errors of metabolism in adults

The discovery of a leukoencephalopathy is a frequent situation in neurological practice and the diagnostic approach is often difficult given the numerous possible aetiologies, which include multiple acquired causes and genetic diseases including inborn errors of metabolism (IEMs). It is now clear that IEMs can have their clinical onset from early infancy until late adulthood. These diseases are particularly important to recognize because specific treatments often exist. In this review, illustrated by personal observations, we give an overview of late-onset leukoencephalopathies caused by IEMs.

Movement disorders and inborn errors of metabolism in adults: a diagnostic approach

Inborn errors of metabolism (IEMs) may present in adolescence or adulthood with various movement disorders including parkinsonism, dystonia, chorea, tics or myoclonus. Main diseases causing movement disorders are metal-storage diseases, neurotransmitter synthesis defects, energy metabolism disorders and lysosomal storage diseases. IEMs should not be missed as many are treatable. Here we briefly review IEMs causing movement disorders in adolescence and adults and propose a simple diagnostic approach to guide metabolic investigations based on the clinical course of symptoms, the type of abnormal movements, and brain MRI abnormalities.

[Treatable hereditary neuro-metabolic diseases]

Hereditary metabolic diseases may appear during adolescence or young adulthood, revealed by an apparently unexplained neurological or psychiatric disorder. Certain metabolic diseases respond to specific treatments and should be identified early, particularly in emergency situations where rapid introduction of a treatment can avoid fatal outcome or irreversible neurological damage. The main diseases leading to an acute neurological syndrome in the adult are urea cycle disorders, homocysteine metabolisms disorders and porphyria. More rarely, Wilson's disease, aminoacid diseases, organic aciduria, or pyruvate dehydrogenase deficiency, beta-oxidation disordes or biotin metabolism may be involved. Most emergency situations can be screen correctly with simple tests (serum ammonia, homocysteine, lactate, urinary prophyrines, acylcarnitine pattern, amino acid and organic acid chromatography). For chronic situations, the main treatable diseases are Wilson's disease, homocysteine, cerebrotendinous xanthomatosis, Refsum's disease, vitamin E deficiency, Gaucher's disease, Fabry's disease, and neurotransmitter metabolism disorders. We present treatable metabolic disorders as a function of the different clinical situations observed in adults.

[Neurological presentations of lysosomal diseases in adult patients]

Lysosomal diseases represent a large group of genetic storage disorders characterized by a defect in the catabolism of complex molecules within the lysosome. Effective treatments are now possible for some of them given progresses in bone-marrow transplantation, enzyme replacement therapy and substrate reduction therapy. Neurologists and psychiatrists are concerned by these diseases because they can present in adolescence or adulthood with progressive neuropsychiatric signs. Here we focus on late-onset clinical forms which can be met in an adult neurology or psychiatric department. Lysosomal diseases were classified into 3 groups: (1) leukodystrophies (metachromatic leukodystrophy, Krabbe's disease and Salla's disease); (2) Neurodegenerative or psychiatric-like diseases (GM1 and GM2 gangliosidoses, Niemann Pick type C disease, sialidosis type I, ceroid-lipofuscinosis, mucopolysaccharidosis type III); (3) multisystemic diseases (Gaucher's disease, Fabry's disease, alpha and B mannosidosis, Niemann Pick disease type B, fucosidosis, Schindler/Kanzaki disease, and mucopolysaccharidosis type I and II. We propose a diagnostic approach guided by clinical examination, brain MRI, electrodiagnostic studies and abdominal echography.

Hereditary spastic paraparesis in adults associated with inborn errors of metabolism: a diagnostic approach

Spastic paraparesis is a general term describing progressive stiffness and weakness in the lower limbs caused by pyramidal tract lesions. This clinical situation is frequently encountered in adult neurology. The diagnostic survey is usually limited to searching for acquired causes (spinal cord compression, inflammatory, metabolic, infectious diseases) and the so-called 'hereditary spastic paraparesis'. Although poorly recognized by neurologists, spastic paraparesis is also one of the multiple presentations of inborn errors of metabolism (IEMs) in children and adults. Pyramidal signs are usually included in a diffuse neurological or systemic clinical picture; however, in some cases spastic paraparesis remains the only symptom for years. Since these metabolic causes are often treatable, it is essential to include them in the general diagnostic approach to spastic paraparesis. Here we review IEMs causing paraparesis in adults.

Epilepsy and inborn errors of metabolism in adults: a diagnostic approach

Inborn errors of metabolism (IEMs) represent poorly known causes of epilepsy in adulthood. Although rare, these are important to recognize for several reasons: some IEMs respond to specific treatments, some antiepileptic drugs interfering with metabolic pathways may worsen the clinical condition, and specific genetic counselling can be provided. We review IEMs potentially revealed by epilepsy that can be encountered in an adult neurology department. We distinguished progressive myoclonic epilepsies (observed in some lysosomal storage diseases, respiratory chain disorders and Lafora disease), from other forms of epilepsies (observed in disorders of intermediary metabolism, including porphyrias, creatine metabolism defects, glucose transporter (GLUT-1) deficiency, Wilson disease or succinic semialdehyde dehydrogenase deficiency). We propose a diagnostic approach and point out clinical, radiological and electrophysiological features that suggest an IEM in an epileptic patient.

Psychiatric manifestations revealing inborn errors of metabolism in adolescents and adults

Inborn errors of metabolism (IEMs) may present in adolescence or adulthood as a psychiatric disorder. In some instances, an IEM is suspected because of informative family history or because psychiatric symptoms form part of a more diffuse clinical picture with systemic, cognitive or motor neurological signs. However, in some cases, psychiatric signs may be apparently isolated. We propose a schematic classification of IEMs into three groups according to the type of psychiatric signs at onset. Group 1 represents emergencies, in which disorders can present with acute and recurrent attacks of confusion, sometimes misdiagnosed as acute psychosis. Diseases in this group include urea cycle defects, homocysteine remethylation defects and porphyrias. Group 2 includes diseases with chronic psychiatric symptoms arising in adolescence or adulthood. Catatonia, visual hallucinations, and aggravation with treatments are often observed. This group includes homocystinurias, Wilson disease, adrenoleukodystrophy and some lysosomal disorders. Group 3 is characterized by mild mental retardation and late-onset behavioural or personality changes. This includes homocystinurias, cerebrotendinous xanthomatosis, nonketotic hyperglycinaemia, monoamine oxidase A deficiency, succinic semialdehyde dehydrogenase deficiency, creatine transporter deficiency, and alpha and beta mannosidosis. Because specific treatments should be more effective at the 'psychiatric stage' before the occurrence of irreversible neurological lesions, clinicians should be aware of atypical psychiatric symptoms or subtle organic signs that are suggestive of an IEM. Here we present an overview of IEMs potentially revealed by psychiatric problems in adolescence or adulthood and provide a diagnostic strategy to guide metabolic investigations.

Peripheral neuropathy and inborn errors of metabolism in adults

Although they are classically viewed as paediatric diseases, it is now recognized that inborn errors of metabolism (IEMs) can present at any age from childhood to adulthood. IEMs can involve the peripheral nervous system, mostly as part of a more diffuse neurological or systemic clinical picture. However, in some cases, the neuropathy can be the unique initial sign. Here, based on our personal experience and on a comprehensive literature analysis, we review IEMs causing neuropathies in adults. Diseases were classified according to the predominant type of neuropathies into (1) acute neuropathies, (2) mononeuropathy multiplex, (3) chronic axonal polyneuropathies, (4) chronic demyelinating polyneuropathies, (5) small-fibre neuropathies, and (6) lower motor neuron disease.

Troubles neurologiques par carence en vitamine B12 déclenchés par le protoxyde d’azote

INTRODUCTION

Nitrous oxide is frequently used for anesthesia. It may cause spinal cord toxicity.

CASE REPORTS

We report two patients who presented gait disorders after nitrous oxide anesthesia. Physical examination revealed arms and legs pyramidal syndrome and abnormal proprioception, consistent with subacute combined degeneration of the spinal cord. Serum vitamin B12 level was extremely low. The patients improved with parenteral treatment with hydroxycobalamin.

CONCLUSIONS

The inactivation of methionine synthase and L methylmalonylcoA mutase by nitrous oxide has been previously demonstrated. Anesthesia-related exposure to nitrous oxide may induce neurologic disorders even in patients with no preliminary vitamin B12 deficiency.

Dihydropteridine reductase deficiency: Levodopa's long-term effectiveness without dyskinesia

We report an adult patient lacking endogenous synthesis of monoamines (dopamine, serotonin, and catecholamines) due to a severe dihydropteridine reductase (DHPR) deficiency. With levodopa and 5-hydroxytryptophan (5HTP) supplementation, the patient exhibited moderate mental retardation, acute episodes of parkinsonism, and episodes of depression. Despite the use of levodopa from age 3 months, he exhibited no dyskinesia or dopaminergic cell loss as suggested by normal PET imaging of the dopamine transporter.

[Neurological manifestations of type 1 Gaucher's disease: Is a revision of disease classification needed?]

INTRODUCTION

Gaucher's disease (GD), the most prevalent inherited lysosomal storage disorder, is caused by deficient glucocerebrosidase activity. The resulting accumulation of glucocerebrosides in lysosomes of macrophages leads to hepatosplenomegaly, anemia, thrombocytopenia, and various bone manifestations. Gaucher's disease is classified into 3 types based on the nature of its effects on the central nervous system. Type 1, the most common variant, is classically nonneuronopathic. However, the occurrence of Parkinsonism seems to be more frequent in type I Gaucher's disease than in the general population. Furthermore, heterozygotes for certain glucocerebrosidase gene mutations have a higher risk to develop Parkinson's disease.

OBSERVATIONS

We report our experience about 9 patients with Gaucher's disease and their association with neurological manifestations.

CONCLUSION

These recent data may discuss Gaucher's classification and the existence of a continuum between neurologic and non-neurologic forms of the disease.

Clinical approach to treatable inborn metabolic diseases: an introduction

In view of the major improvements in treatment, it has become increasingly important that in order for first-line physicians not to miss a treatable disorder they should be able initiate a simple method of clinical screening, particularly in the emergency room. We present a simplified classification of treatable inborn errors of metabolism in three groups. Group 1 includes inborn errors of intermediary metabolism that give rise to an acute or chronic intoxication. It encompasses aminoacidopathies, organic acidurias, urea cycle disorders, sugar intolerances, metal disorders and porphyrias. Clinical expression can be acute or systemic or can involve a specific organ, and can strike in the neonatal period or later and intermittently from infancy to late adulthood. Most of these disorders are treatable and require the emergency removal of the toxin by special diets, extracorporeal procedures, cleansing drugs or vitamins. Group 2 includes inborn errors of intermediary metabolism that affect the cytoplasmic and mitochondrial energetic processes. Cytoplasmic defects encompass those affecting glycolysis, glycogenosis, gluconeogenesis, hyperinsulinisms, and creatine and pentose phosphate pathways; the latter are untreatable. Mitochondrial defects include respiratory chain disorders, and Krebs cycle and pyruvate oxidation defects, mostly untreatable, and disorders of fatty acid oxidation and ketone bodies that are treatable. Group 3 involves cellular organelles and includes lysosomal, peroxisomal, glycosylation, and cholesterol synthesis defects. Among these, some lysosomal disorders can be efficiently treated by enzyme replacement or substrate reduction therapies. Physicians can be faced with the possibility of a treatable inborn error in an emergency, either in the neonatal period or late in infancy to adulthood, or as chronic and progressive symptoms--general (failure to thrive), neurological, or specific for various organs or systems. These symptoms are summarized in four tables. In addition, an extensive list of medications used in the treatment of inborn errors is presented.

[Adult onset hereditary leukoencephalopathies]

In clinical practice, the term "genetic leukoencephalopathy" refers to a group of genetic diseases whose common point is to give an aspect of diffuse leukoencephalopathy on MRI. With progress in diagnostic techniques including radiology, biochemistry or genetics, a large number of hereditary diseases causing leukoencephalopathy have been identified. Although generally beginning in childhood, these diseases often have more insidious clinical forms which can begin in adulthood. These forms remain poorly known. Some are accessible to treatment so their diagnosis appears essential. The diagnostic steps must be guided by clinical examination (neurological, ophthalmological and systemic), electromyography and MRI. The purpose of this review is to propose a classification of the genetic leukoencephalopathies and to give a progress report applicable in neurological practice.

[Isolated ptosis in a 58-year-old woman]

A 60-year-old woman who had experienced isolated ptosis for two years was seen when it had been fixed for one year. She had a personal and familial history of stromal corneal dystrophy. The diagnosis of mitochondrial cytopathy was made on the basis of clinical, electrophysiological, biological and histological findings. Surgical repair of the ptosis allowed visual recovery. The relationship between ptosis, corneal dystrophy and mitochondrial cytopathy is discussed.

Nerve growth factor (NGF) induces motoneuron apoptosis in rat embryonic spinal cord in vitro

Recent studies have demonstrated that nerve growth factor (NGF) induces apoptosis of several cell types in the central nervous system through its low-affinity p75 neurotrophin receptor (p75NTR). To test the effect of NGF on embryonic motoneuron survival, we developed an organotypic culture system which allowed the in vitro development of intact embryonic rat spinal cords. In our system, neural tubes were taken and cultured at E13, just before the onset of physiological motoneuron death. After 2 days in vitro (DIV), motoneurons underwent apoptosis over a time-course similar to that in vivo. In this system, the addition of NGF (200 ng/mL) for 2 days enhanced the number of apoptotic motoneurons by 37%. This pro-apoptotic effect was completely reversed by the blocking anti-p75NTR (REX) antibody which inhibits NGF binding to p75NTR. Other neurotrophins, e.g. brain-derived neurotrophic factor (BDNF), neurotrophin 3 (NT3) and neurotrophin 4/5 (NT4/5) did not have any effect, while glial cell-derived neurotrophic factor (GDNF) promoted motoneuron survival. Anti-BDNF blocking antibodies enhanced motoneuron death indicating that endogenous BDNF promotes motoneuron survival in explants. Our results demonstrate, for the first time, that NGF can induce embryonic motoneuron apoptosis through its receptor p75NTR.