[Peripartum cardiomyopathy: incidence, pathogenesis, diagnosis, treatment and prognosis]

INTRODUCTION

Peripartum cardiomyopathy (PPCM) is a rare and life-threatening disease of unknown aetiology. The primary objective of this review was to analysed aetiopathogeneses, clinical presentation and diagnosis, as well as pharmacological, perioperative and intensive care management and prognosis of this pathology.

METHODS

We undertook a systematic review of the literature using Medline, Google Scholar and PubMed searches.

RESULTS

Unlike other parts of the world in which cardiomyopathy are rare, dilated cardiomyopathy is a major cause of heart failure throughout Africa. Its aetiopathogenesis is still poorly understood, but recent evidence supports inflammation, viral infection and autoimmunity as the leading causative hypotheses. This diagnosis should be limited to previously healthy women who present with congestive heart failure (CHF) and decreased left ventricular systolic function in the last month of pregnancy or within 5 months after delivery. Recently, introduction of echocardiography has made diagnosis of PPCM easier and more accurate. Conventional treatment consists of diuretics, vasodilators, and sometimes digoxin and anticoagulants, usually in combination. Patients who fail to recover may require inotropic therapy. In resistant cases, newer therapeutic modalities such as immunomodulation, immunoglobulin and immunosuppression may be considered. Prognosis is highly related to reversal of ventricular dysfunction. Compared to historically higher mortality rates, recent reports describe better outcome, probably because of advances in medical care. Based on current information, future pregnancy is usually not recommended in patients who fail to recover normal heart function.

CONCLUSION

PPCM is a rare but serious form of cardiac failure affecting women in the last months of pregnancy or early puerperium. Its aetiopathogenesis is still poorly understood. Introduction of echocardiography has made diagnosis of PPCM easier and more accurate. Prognosis is highly related to reversal of ventricular dysfunction.

[Prognostic factors of pneumococcal meningitis. Retrospective study of 31 cases]

AIM

Our aim was to study the susceptibility of Streptococcus pneumoniae to antibiotics in patients with pneumococcal meningitis and to search for the prognosis factors in those patients.

METHODS

We have studied retrospectively 31 cases of pneumococcal meningitis. Comparaisons were performed with univariate analysis.

RESULTS

The mean age was 36.7 +/- 20.5 years (ranged: 9 and 78 years). The sex ratio was 3,4. The susceptibility of Streptococcus pneumoniae to penicillin G was affected in 10 cases (33% of isolated pneumococcus. The MIC to penicillin G was > or =2 in only one case. The hospital mortality was 26% (8/31). With univariate analysis, factors associated with death were: age > or =55 years (Ss p= 0,006, OR: 17.2 IC95%: 2.3-134), albuminorachie > or = 7 g/l (p = 0.002, OR: 22; IC95%: 1.9-2.51), shock (p = 0.031, OR: 6.7; IC95%: 1.05-42) and Glasgow Coma Score (GCS) < or =8 (p = 0.001, OR: 20; IC95%: 2.68-149).

CONCLUSION

No susceptibility to penicillin G is not associated with a worse outcome in patients with pneumococcal meningitis. An age > or =55 years, albuminorachie > or =7 g/l shock and Glasgow Coma Score < or =8 at admission were determinant of the prognosis in our study.

Safety and efficacy of colistin compared with imipenem in the treatmentof ventilator-associated pneumonia: a matched case–control study

OBJECTIVE

Our study aimed to determine the efficacy and safety of colistin in the treatment of ventilator-associated pneumonia (VAP) caused by pan-drug-resistant Pseudomonas aeruginosa or Acinetobacter baumanii.

DESIGN

Pairwise, retrospective exposed-unexposed study.

SETTING

Combined medical and surgical intensive care unit of Habib Bourguiba University Hospital (Sfax, Tunisia).

PATIENTS

Sixty patients with VAP caused by pan-drug-resistant A. baumanii or P. aeruginosa matched to 60 controls with VAP caused by A. baumanii or P. aeruginosa susceptible to imipenem. All patients had normal renal function at the onset of antibiotic therapy.

INTERVENTIONS

Case patients were treated by colistin intravenously and control patients were treated by imipenem intravenously.

MEASUREMENTS AND RESULTS

Baseline characteristics were similar between the colistin and imipenem groups. The mean duration of antibiotic therapy for VAP was 9.5+/-3.8 days (range 5-22 days) with colistin and 8.9+/-2.8 days (range 5-20 days) with imipenem (p=0.32). A favorable clinical response to antibiotic therapy for VAP occurred in 45 patients (75%) in the colistin group and in 43 patients (71.7%) in the imipenem group (p=0.68). The time to resolution of infectious parameters after the initiation of antibiotic therapy was not statistically different between the two groups. During the antibiotic course, none of the patients in either group developed renal failure.

CONCLUSIONS

We conclude that colistin can be a safe and effective option in the treatments of VAP caused by pan-drug-resistant P. aeruginosa or A. baumanii.

[Thrombotic microangiopathies. Incidence, pathogenesis, diagnosis, treatment and prognosis]

INTRODUCTION

The objective of this work was to review current data about the pathophysiology, clinical features, and treatment of thrombotic microangiopathies.

CURRENT KNOWLEDGE

Thrombotic microangiopathies are microvascular occlusive disorders characterized by systemic or intrarenal aggregation of platelets, thrombocytopenia, and mechanical injury to erythrocytes. In thrombotic thrombocytopenic purpura, systemic microvascular aggregation of platelets causes ischemia in the brain and other organs. In the hemolytic-uremic syndrome, platelet-fibrin thrombi occlude predominantly the renal circulation. Thrombotic microangiopathy is a rare disorder whose varied clinical manifestations result from the formation of platelet-rich thrombi within the microvasculature and consequent tissue ischemia. The clinical features are acute renal failure, microangiopathic hemolytic anemia and thrombocytopenia. This diagnosis is of considerable importance because of the possible fulminant clinical course. Some atypical forms may be unrecognized. Plasma exchange is the current reference treatment of thrombotic thrombocytopenic purpura. However, in the light of recent publications, either infusions of concentrates of purified enzyme or more intensive immunosuppressive therapy would be more specific.

[Traumatic unilateral renal artery thrombosis and protein C deficiency. A case report]

Post traumatic renal artery thrombosis is rarely described in the literature. This pathology can result from stretch injury to inelastic intima of the renal artery, or by the direct flow to the abdomen causing compression injury to the renal artery against the vertebral column. However, the association of this pathology with hematologic diseases (in particular protein C deficit) was never described. We report an observation of a 28-year-old man with an uneventful history who was admitted to the intensive care unit for traumatic head injury associated with post traumatic renal artery thrombosis requiring nephrectomy. The etiologic investigation of this thrombo-embolic complication reveals a protein C deficit. Our patient was improved under treatment. This original observation confirms that post traumatic renal artery thrombosis can be associated with hematologic diseases (in particular protein C deficit).

Les microangiopathies thrombotiques en réanimation

OBJECTIVES

To analyze the clinico-biological manifestations, identify the causes and evaluate the outcome of patients with severe thrombotic microangiopathies admitted in a Tunisian intensive care unit.

METHODS

Retrospective study over a period of 10 years (1995-2004) in an intensive care unit.

RESULTS

Were included in this study 9 cases with a mean age of 29.2+/-9 years (range 15-44 years). Fever was observed in 5 patients, neurological impairment in 5 and digestive manifestations in 6. Haemolytic anaemia, thrombocytopenia and acute renal failure were observed in 100% of the cases. In our study, the aetiologies of thrombotic microangiopathies were: complicated pregnancy in 6 cases, systemic lupus erythematosus in 1 case. In contrast, no aetiology was found in 2 patients. Plasma exchange was performed in 5 patients, while 4 patients received only plasma infusion. After an average stay of 18+/-12.5 days, evolution was marked by the death 3 patients.

CONCLUSION

The incidence of severe thrombotic microangiopathies is rare in Tunisian ICU. The clinical manifestations are not specific. Despite the improvement in the outcome by exogenous plasma supply, thrombotic microangiopathies with severe organ dysfunctions leading to hospitalization in the intensive care unit are associated with a high mortality rate.

Stéatose hépatique aiguë gravidique. À propos de 22 cas

OBJECTIVE

To report the clinical experience, biochemical findings, complications and maternal outcome in patients with acute fatty liver of pregnancy (AFLP).

PATIENTS AND METHODS

Retrospective study over a period of 11 years (1993-2003). The diagnosis of AFLP was confirmed by liver biopsy in 15 women. However, in 7 women a medical committee that took into account clinical symptoms, and laboratory findings assessed the diagnosis.

RESULTS

Were included in this study, 22 women with a mean age of 30+/-5.4 years. Only 22.7% of cases were primigravid. The mean gestational age was 36+/-2.76 weeks (range 31-41 weeks). The fetus was a male infant in 75% of cases. Ten women were admitted in the hospital without jaundice. However 15 women had developed an icterus since their hospital admission or during ICU stay. The mean SAPS II on the ICU admission was of 24.86+/-11.2 points. Biological disturbances observed were mainly: liver cytolysis in 91% of cases, a trend to hypoglycaemia in 86%, a hypoprotidemia in 66.7% and CIVD in 32%. During their ICU stay, 19 women (86.4%) developed one or several organ failures associated to the hepatic failure and 18 women required blood transfusion. After an average stay of 7.5 days, evolution was marked by the death of seven patients (31.8%). Factors correlated with a poor prognosis were: the delay of medical consultation, the development of jaundice, the development of encephalopathy, respiratory or a circulatory failure.

DISCUSSION AND CONCLUSION

AFLP is a rare but life-threatening complication. Furthermore AFLP shares features with other more common and less perilous illnesses. An early diagnosis and appropriate therapy of this pathology should improve the poor prognosis in our country.

Maladie cœliaque, thrombose veineuse cérébrale et déficit en protéine S, Une association fortuite ?

INTRODUCTION

Celiac disease is a pathology which is rarely associated with thrombosis complications. Cerebral vascular thrombosis has never been described in patients with a celiac disease.

OBSERVATION

We report an observation of a 21-year-old girl with a history of celiac disease who was hospitalized in the intensive care unit for convulsive status epilepticus secondary to a cerebral venous thrombosis. The etiologic investigation of this thrombo-embolic complication revealed protein S deficit. Our patient improved under symptomatic treatment.

COMMENT

This original observation confirms that celiac disease can be associated with cerebral venous thrombosis.

Prevalence of hospital-acquired infection in a Tunisian hospital

In order to estimate the prevalence of hospital-acquired infection (HAI) and research factors associated with its occurrence, a one-day prevalence survey was conducted at the Habib Bourguiba University Hospital, Tunisia. We studied 280 patients who had been present in the same ward for at least 48 h, and who had occupied a hospital bed between 17 April 2002 (midnight) and 18 April 2002 (midnight). The overall prevalence of HAI was 17.9%. The most frequently infected sites were the lungs (32%), surgical wounds (28%) and the urinary tract (20%). Microbiological documentation was available in only 28% of HAIs, and the most frequently isolated organisms were Gram-negative rods (80.8%). Results of multiple logistic regression analysis indicated that HAI is linked to the medical category, the use of intravascular devices and antibiotic prophylaxis. This survey provided information on the prevalence of HAI in Tunisian hospitals, the breakdown of infections, and HAI predisposing factors.

[Evaluation of the antibiotics consumption in a Tunisian university hospital]

PURPOSE

To estimate the consumption of antibiotics in our hospital and to determine the points at which will be targeted the recommendations of good practice of antibiotherapy.

PATIENTS AND METHODS

Our study is a one day prevalence study where antibiotic's prescriptions are analyzed by a group of 6 doctors referents in antibiotherapy.

RESULTS

During the study day, 443 patients were studied. Means age was 44.2 +/- 23.3 years (range: 1 and 102 years). 101 infections were diagnosed in 48 patients (10.8%). 192 patients (43.3%) received antibiotics. Antibiotherapy was curative in 44% of cases. The most prescribed antibiotics were gentamicin (85.2 DDD/1000 patients), metronidazole (79 DDD/1000 patients), and cefotaxime (73.9 DDD/1000 patients). According to the evaluation group, 30.7% of the antibiotic's prescription was considered unjustified. The antibioprophylaxis represents the category most often unjustified (49%). The molecules in which prescription was frequently considered unjustified are the ciprofloxacin (67%), the amoxicilline-clavulanate (40%) and the cefotaxime (40%).

CONCLUSION

Our results suggest that an action of good practice should be targeted at the antibioprophylaxis and should concern especially molecules in which prescription was frequently unjustified.

Phenotype and sarcoglycan expression in Tunisian LGMD 2C patients sharing the same del521-T mutation

Limb-girdle muscular dystrophy type 2C is an autosomal recessive muscular disorder caused by mutations in the gene encoding the gamma-sarcoglycan subunit. This gamma-sarcoglycanopathy is prevalent in Tunisia where only one homozygous mutation a 521-T deletion has been identified. The aim of this study was to carry out a comparative clinical and immunocytochemical analysis of Tunisian patients sharing the same gamma-sarcoglycan gene mutation. One hundred and thirty-two patients were classified as severe, moderate or mild according to a calculated severity score. Heterogeneous phenotypes between siblings were encountered in 75% of the families. The severity of the disease was not found to be related to the age of onset. Immunohistochemical studies of muscle biopsy showed a total absence of gamma-sarcoglycan, a normal or slightly reduced alpha and delta-sarcoglycans whereas the expression of beta-sarcoglycan was variable. The residual sarcoglycan expression was not related to the clinical phenotype. In conclusion, the phenotypic variability in sarcoglycanopathies in Tunisia seems to involve a modifying gene controlling the course of the disease.

[Hemolytic-uremic syndrome secondary to scorpion envenomation (apropos of 2 cases)]

HUS was recently described following scorpion sting. We report 2 cases of HUS in the intensive care unit of a university hospital. Two children aged respectively 10 months and 1 year were admitted in the ICU after severe scorpion envenomation (with coma and pulmonary oedema) having required dobutamine and mechanical ventilation. Evolution was marked with acute anaemia without bleeding requiring blood transfusion, acute renal failure, low platelets and signs of haemolysis. Our experience and the previously reported case suggest that scorpion sting could be added to the list of causes of the HUS.

Linkage of a new locus for autosomal recessive axonal form of Charcot-Marie-Tooth disease to chromosome 8q21.3

We report the clinical and genetic linkage analysis of a large Tunisian family with thirteen affected patients suffering from Charcot-Marie-Tooth disease with pyramidal involvement. The inheritance is autosomal recessive. The clinical phenotype is consistent in all patients. It is characterized by onset during the first decade, a progressive course and distal atrophy in all four limbs, associated with a mild pyramidal syndrome. Nerve biopsy in two patients showed severe axonal neuropathy. Genetic linkage excluded known loci of different genetic forms of Charcot-Marie-Tooth disease, familial spastic paraplegia and familial amyotrophic lateral sclerosis. A significant lod score was obtained with marker D8S286, confirming linkage to chromosome 8q21.3. The clinical syndrome observed in this family seems to correspond to a new genetic form of autosomal recessive Charcot-Marie-Tooth disease.

Perlecan, the major proteoglycan of basement membranes, is altered in patients with Schwartz-Jampel syndrome (chondrodystrophic myotonia)

Schwartz-Jampel syndrome (SJS1) is a rare autosomal recessive disorder characterized by permanent myotonia (prolonged failure of muscle relaxation) and skeletal dysplasia, resulting in reduced stature, kyphoscoliosis, bowing of the diaphyses and irregular epiphyses. Electromyographic investigations reveal repetitive muscle discharges, which may originate from both neurogenic and myogenic alterations. We previously localized the SJS1 locus to chromosome 1p34-p36.1 and found no evidence of genetic heterogeneity. Here we describe mutations, including missense and splicing mutations, of the gene encoding perlecan (HSPG2) in three SJS1 families. In so doing, we have identified the first human mutations in HSPG2, which underscore the importance of perlecan not only in maintaining cartilage integrity but also in regulating muscle excitability.

The gene encoding gigaxonin, a new member of the cytoskeletal BTB/kelch repeat family, is mutated in giant axonal neuropathy

Disorganization of the neurofilament network is a prominent feature of several neurodegenerative disorders including amyotrophic lateral sclerosis (ALS), infantile spinal muscular atrophy and axonal Charcot-Marie-Tooth disease. Giant axonal neuropathy (GAN, MIM 256850), a severe, autosomal recessive sensorimotor neuropathy affecting both the peripheral nerves and the central nervous system, is characterized by neurofilament accumulation, leading to segmental distension of the axons. GAN corresponds to a generalized disorganization of the cytoskeletal intermediate filaments (IFs), to which neurofilaments belong, as abnormal aggregation of multiple tissue-specific IFs has been reported: vimentin in endothelial cells, Schwann cells and cultured skin fibroblasts, and glial fibrillary acidic protein (GFAP) in astrocytes. Keratin IFs also seem to be alterated, as most patients present characteristic curly or kinky hairs. We report here identification of the gene GAN, which encodes a novel, ubiquitously expressed protein we have named gigaxonin. We found one frameshift, four nonsense and nine missense mutations in GAN of GAN patients. Gigaxonin is composed of an amino-terminal BTB (for Broad-Complex, Tramtrack and Bric a brac) domain followed by a six kelch repeats, which are predicted to adopt a beta-propeller shape. Distantly related proteins sharing a similar domain organization have various functions associated with the cytoskeleton, predicting that gigaxonin is a novel and distinct cytoskeletal protein that may represent a general pathological target for other neurodegenerative disorders with alterations in the neurofilament network.

A new locus for autosomal recessive limb-girdle muscular dystrophy in a large consanguineous Tunisian family maps to chromosome 19q13.3

Autosomal recessive limb-girdle muscular dystrophies represent a genetically heterogeneous group of diseases characterized by a progressive involvement of skeletal muscles. They show a wide spectrum of clinical courses, varying from very mild to severe. Eight loci responsible for autosomal recessive limb-girdle muscular dystrophies have been mapped and six defective genes identified. In this study, we report the clinical data, muscle biopsy findings and results of genetic linkage analysis in a large consanguineous Tunisian family with 13 individuals suffering from autosomal recessive limb-girdle muscular dystrophy. Clinical features include variable age of onset, proximal limb muscle weakness and wasting predominantly affecting the pelvic girdle, and variable course between siblings. CK rate was usually high in younger patients. Muscle biopsy showed dystrophic changes with normal expression of dystrophin and various proteins of the dystrophin-associated protein complex (sarcoglycan sub-units, dystroglycan, and sarcospan). Genetic linkage analysis excluded the known limb-girdle muscular dystrophies loci as well as ten additional candidate genes. A maximum LOD score of 4.36 at &theta;=0.00 was obtained with marker D19S606, mapping this new form of autosomal recessive limb-girdle muscular dystrophy to chromosome 19q13.3.

Linkage to chromosome 13q11-12 of an autosomal recessive cerebellar ataxia in a Tunisian family

OBJECTIVE

To report the clinical findings and the genetic linkage mapping of an autosomal recessive cerebellar ataxia associated to peripheral neuropathy, showing an early onset cerebellar ataxia with retained tendon reflexes (EOCA) phenotype.

BACKGROUND

EOCA is a clinical syndrome delimited by Harding distinguished from Friedreich's ataxia (FA) mainly by the preservation of tendon reflexes. Molecular genetic study of patients with EOCA has demonstrated genetic heterogeneity. A form of autosomal recessive spastic ataxia has been described in Charlevoix Saguenay area in Quebec (ARSACS); the gene responsible has been mapped to chromosome 13q.

METHODS

Genetic linkage analysis was performed on 18 members of a large family including 8 of 9 members with EOCA. After exclusion of FA and ataxia with vitamin E deficiency loci as well as loci of autosomal dominant cerebellar ataxias, we performed a linkage analysis to markers of 13q11-12 region.

RESULTS

The 9 affected members of this family showed stereotyped clinical features with cerebellar ataxia, pyramidal syndrome, and a variable degree of axonal peripheral neuropathy. Linkage was detected between the disease locus and the microsatellite marker D13S232. Surrounding markers to D13S232 confirmed the linkage and showed the homozygosity of the affected members.

CONCLUSION

The family reported here showed the same locus as autosomal recessive spastic ataxia Charlevoix Saguenay disease.

Shorter telomeres in dystrophic muscle consistent with extensive regeneration in young children

Muscular dystrophies are characterised by continuous cycles of degeneration and regeneration resulting in an eventual diminution of the muscle mass and extensive fibrosis. In somatic cells chromosomal telomeres shorten with each round of cell division and telomere length is considered to be a biomarker of the replicative history of the cell. We have previously shown that human myoblasts have a limited proliferative capacity, and that normal skeletal muscle has a very low level of nuclear turnover. However, in patients suffering from muscular dystrophy the satellite cells will be forced to make repeated rounds of cell division, driving the cells towards senescence. In this study we have used the telomere length to quantify the intensity of the muscle cell turnover in biopsies from dystrophic patients of different ages. Our results show that as soon as the first clinical symptoms become apparent the muscle has already undergone extensive regeneration and the rate of telomere loss is 14 times greater than that observed in controls. This confirms that the decline in regenerative capacity is due to the premature senescence of the satellite cells induced by their excessive proliferation during muscle repair.

Electrophysiology and nerve biopsy: comparative study in Friedreich's ataxia and Friedreich's ataxia phenotype with vitamin E deficiency

The authors report a comparative study of peripheral nerve conductions and nerve biopsy and somatosensory evoked potentials between 15 patients with Friedreich's ataxia and 15 patients with Friedreich's ataxia phenotype with selective vitamin E deficiency. The patients in the two groups are of similar age, age of onset, and clinical phenotype. Peripheral motor nerve action potential amplitude, and conduction velocities are within normal ranges in the two groups. In the Friedreich's ataxia group there is an early and severe peripheral sensory axonal neuronopathy, characterised by an important reduction of the amplitude of sensory action potential, and important loss of myelinated fibres with complete disappearance of large myelinated fibres without any regenerative process. In the Friedreich's ataxia phenotype with selective vitamin E deficiency group there is slight-to-moderate axonal sensory neuropathy with normal to moderate decrease of large myelinated fibre density and important regeneration in nerve biopsy. Somatosensory evoked potentials are markedly involved in the two groups asserting a severe involvement of somatosensory pathway in lumbar, thoracic and cervical spinal cord. These findings suggest that the pathological mechanism involved in the two diseases are different: central peripheral axonopathy in Friedreich's ataxia and central distal axonopathy in Friedreich's ataxia phenotype with selective vitamin E deficiency.

LGMD 2E in Tunisia is caused by a homozygous missense mutation in beta-sarcoglycan exon 3

Four of the currently recognized autosomal recessive limb-girdle muscular dystrophies (LGMD type 2C-F) are caused by mutations in the genes encoding components of the sarcoglycan complex. LGMD 2C, caused by mutations in gamma-sarcoglycan, is prevalent in northern Africa, especially in Tunisia, where this type of muscular dystrophy was originally described. Although the disease initially was assumed to be genetically homogeneous in this region, linkage to the alpha-sarcoglycan locus (LGMD 2D) has also been found. We have now identified the first Tunisian family with beta-sarcoglycanopathy (LGMD 2E), further adding to the genetic heterogeneity of autosomal recessive LGMD in this population. Direct sequencing of the beta-sarcoglycan gene revealed a homozygous mutation (G272-->T, Arg91Leu) in exon 3. This change affects the same arginine residue in the immediate extracellular domain of the protein that was mutated to a proline (G272-->C, Arg91Pro) in a Brazilian family with a severe form of the disease. Immunohistochemical analysis for the sarcoglycan complex demonstrates absence of the known components of the complex in both of these families. We postulate that the immediate extracellular domain of beta-sarcoglycan may be important for the assembly and/or maintenance of this complex, potentially mediated by disulfide-bond formation to another sarcoglycan via the single cysteine residue in that domain.

Atypical ataxia telangiectasia with early childhood lower motor neuron degeneration: a clinicopathological observation in three siblings

We report three brothers belonging to a consanguineous family and suffering from ataxia telangiectasia with severe early neurogenic amyotrophy. Pathological examination of the brain and spinal cord in one of them showed Purkinje cell loss with empty baskets and numerous axonal spheroids, dorsal column demyelination with astrocytic proliferation and severe anterior horn cell degeneration. We consider these pathological findings to be related to Louis-Bar disease. Anterior horn cell changes may be one of the early pathological features in ataxia telangiectasia.

Homozygosity mapping of giant axonal neuropathy gene to chromosome 16q24.1

Giant axonal neuropathy (GAN) is a rare autosomal recessive disorder described as a symmetrical distal neuropathy, with peripheral axons dilated by accumulation of 10 nm neurofilaments (NF) and a severe course of the disease. The observation of kinky or curly hairs is not a constant finding. The GAN1 locus was localized by homozygosity mapping to chromosome 16 q24.1 in a 3 (4) cM interval flanked by the markers D16S3073 and D16S505 (D16S511) in three non-related Tunisian families, showing a genetic homogeneity in these families. Two point lod-score calculation between the linked haplotype and the disease locus was 14.2 at theta(max) = 0. The patients share a slow course of the disease. The differences in the course of the disease between Tunisian and non-Tunisian patients suggest a possible genetic heterogeneity, which is why the present linkage has been referred to as GAN1. The biochemical defect in GAN1 should help to understand the mechanisms involved in NF accumulations as in other neurological diseases (ALS, SMA).

Replicative potential and telomere length in human skeletal muscle: implications for satellite cell-mediated gene therapy

In this study, we have evaluated the ability of human satellite cells isolated from subjects aged from 5 days to 86 years to proliferate in culture. Cells were cultivated until they became senescent. The number of cell divisions was calculated by counting the number of cells plated in culture compared to the number of cells removed following proliferation. Telomere length, which is known to decrease during each round of cell division, has been used to analyze the in vitro replicative capacity and in vivo replicative history of human satellite cells at isolation. The rate of telomere shortening in myonuclei of these muscle biopsies was also examined. Our results show that both proliferative capacity and telomere length of satellite cells decreases with age during the first two decades but that the myonuclei of human skeletal muscle are remarkably stable because telomere length in these myonuclei remains constant from birth to 86 years. The lack of shortening of mean terminal restriction fragments (TRF) in vivo confirms that skeletal muscle is a stable tissue with little nuclear turnover and therefore an ideal target for cell-mediated gene therapy. Moreover, our results show that it is important to consider donor age as a limiting factor to obtain an optimal number of cells.

Friedreich's ataxia with isolated vitamin E deficiency: a neuropathological study of a Tunisian patient

The neuropathological findings in a Tunisian patient with Friedreich's ataxia with vitamin E deficiency are reported. The main histological changes are: (1) spinal sensory system demyelination with neuronal atrophy, axonal spheroids and corpora amylacea; (2) neuronal lipofuscin accumulation in the third cortical layer of the cerebral cortex, thalamus, lateral geniculate body, twelfth and ambiguus nuclei, spinal horns and posterior root ganglia. Ultrastructurally, the lipopigments were of uniform granularity without lipid droplets.

Limb-girdle muscular dystrophy 2C: clinical aspects

The LGMD2C linked to chromosome 13q and related to a 35 KDa dystrophin-associated glycoprotein deficiency, is very similar to Duchenne muscular dystrophy with an autosomal recessive inheritance. It is characterized by a variability of the age of onset, the severity of the evolution and the severity of myopathic changes at the muscle biopsy. This variability was also present in the expression of the alpha-sarcoglycan between the same sibships and between different families.

Recessive Schwartz-Jampel syndrome (SJS): confirmation of linkage to chromosome 1p, evidence of genetic homogeneity and reduction of the SJS locus to a 3-cM interval

Schwartz-Jampel syndrome (SJS), or chondrodystrophic myotonia, is a rare autosomal recessive disorder characterized by generalized myotonia resulting in a particular, recognizable facies and osteoarticular abnormalities. Some of us have recently shown genetic linkage of SJS to a locus on 1p34-p36.1 in five families. Here, we show by homozygosity mapping and segregation analysis that eight new families are most likely linked to the SJS locus on chromosome 1, confirming the localization of SJS to chromosome 1p and suggesting genetic homogeneity. Recombination events reduced the SJS locus from a genetic interval of 8 to 3 cM, which should facilitate the identification of the SJS gene. Low clinical variability was observed between the studied families, except for osteoarticular abnormalities. Since the severity and the location of osteoarticular abnormalities varied from one individual to another, even in the same families, other factors than the SJS gene itself, genetic or epigenetic, might contribute to the phenotype.

Localization of the Schwartz-Jampel syndrome (SJS) locus to chromosome 1p34-p36.1 by homozygosity mapping

Schwartz-Jampel syndrome (SJS, MIM 255800), also known as chondrodystrophic myotonia, is a rare autosomal recessive disorder characterized by generalized myotonia, skeletal abnormalities and facial dysmorphism. Using homozygosity mapping, we localized the SJS locus to chromosome 1p34-p36.1 in a 8 cM interval flanked by markers D1S199 and D1S234. Families of different ethnic backgrounds (Tunisia and South Africa) showed genetic linkage to the same locus. Moreover, one Algerian family also demonstrated evidence of genetic linkage to 1p34-p36.1. Taken altogether, our results suggest genetic homogeneity, at least in the group of families analyzed.

Ataxia with vitamin E deficiency: refinement of genetic localization and analysis of linkage disequilibrium by using new markers in 14 families

Ataxia with vitamin E deficiency (AVED) is an autosomal recessive disease characterized clinically by neurological symptoms with often striking resemblance to those of Friedreich ataxia. This disorder has been reported previously as familial isolated vitamin E deficiency. We have mapped recently the AVED locus to a 5-cM confidence interval on chromosome 8q by homozygosity mapping in six Mediterranean families. We have now analyzed six new and two previously described families and demonstrate genetic homogeneity despite important clinical variability and wide geographic origins. Analysis of nine new tightly linked microsatellite markers, including four characterized in this study, revealed a predominant but not unique mutation in northern African populations, where this condition is more frequent. Haplotype analysis but also classical recombinations allowed us to refine the AVED position to a 1-cM interval. A YAC contig over this interval was constructed from marker STSs and YAC fingerprint data, in order to facilitate the search of the AVED gene.

Linkage of Miyoshi myopathy (distal autosomal recessive muscular dystrophy) locus to chromosome 2p12-14

Miyoshi myopathy (MM) is a young-adult-onset, autosomal recessive distal muscular dystrophy initially affecting the plantar flexors. We analyzed 12 MM families, five with consanguineous marriage, for chromosomal linkage using polymorphic microsatellite DNA markers to map the MM gene. A significant lod score was obtained with the 2p12-14 locus D2S291 (Zmax = 15.3 at theta = 0). Two additional 2p12-14 markers, D2S286 (Z = 10.7 at theta = 0) and D2S292 (Z = 7.2 at theta = 0.05), also gave significant lod scores. These markers will be useful for diagnosis of symptomatic and presymptomatic patients, prenatal and carrier diagnosis of family members carrying MM, and ultimately identification of a gene responsible for MM.

Friedreich's ataxia-vitamin E responsive type. The chromosome 8 locus

The most common autosomal recessive ataxia is Friedreich's ataxia (FA), characterized mainly by an early onset, absent tendon reflexes, deep sensory loss, cerebellar and Babinski signs. Screening the patients from families with classical FA features, we found that some families were excluded from the FA locus on chromosome 9, and are associated to isolate vitamin E deficiency. The similarity of the clinical data between FA with and without vitamin E deficiency was remarkable. The disorder with vitamin E deficiency often confused with FA, is currently known as linked to chromosome 8q. Therefore it is important to test vitamin E levels in all patients suspected to have FA, since the alpha tocopherol supplementation may be efficient in early stages of the disease.

Clinical and pathological study of three Tunisian siblings with L-2-hydroxyglutaric aciduria

This report describes three brothers belonging to a consanguineous family suffering from a progressive neurological disorder associated with L-2-hydroxyglutaric aciduria. Clinically this disorder is characterized by childhood onset, pyramidal signs, cerebellar and pseudobulbar syndromes and epilepsy. Pathological examination of the brain in the oldest patient, who died at the age of 30 years, showed bilateral and diffuse spongiosis with notable cystic cavitations of the cerebral white matter without abnormal storage in neurons and glial cells. We consider that these findings are related to L-2 hydroxyglutaric aciduria. To our knowledge this present case represents the first to be reported with neuropathological examination.

[Congenital fibrolipoma of the mesencephalic protuberation area]

BACKGROUND

Congenital origin of brain fibrolipoma is still debated. A case of such a tumor is presented.

CASE REPORT

A female newborn presented with severe hypotonia and macrocephaly that were seen since birth. She died at the age of 2 days. Post-mortem examination showed hydrocephaly due to a tumor located in the mesencephalo-protuberantial region. Histological features of this tumor were those of a fibrolipoma.

CONCLUSION

The presence of this brainstem tumor at birth confirms its congenital origin.

Clinical and genetic analysis of a Tunisian family with autosomal dominant cerebellar ataxia type 1 linked to the SCA2 locus

Autosomal dominant cerebellar ataxias (ADCA) type 1 are a clinically and genetically heterogeneous group of neurodegenerative disorders. We report a large Tunisian ADCA type 1 family in which 17 patients (mean age at onset +/- SD = 35.6 +/- 15.3 years) were examined. There was mean anticipation of 10.3 +/- 15.4 years in this family; anticipation was greater in paternal (28 +/- 8.2 years) than in maternal (2.7 +/- 10.9 years) transmission. Linkage analysis performed with microsatellite markers linked to the spinal cerebellar ataxia 1 (SCA1) locus on chromosome 6p and the SCA2 locus on chromosome 12q excluded linkage to SCA1, but there was close linkage with marker D12S105 (Zmax = 2.51 at theta = 0.00). This result was confirmed by multipoint analysis, which generated a maximal lod score of 3.46 at this locus. Multipoint analysis and haplotype reconstruction reduced the interval containing the SCA2 locus to 6.4 cM, a narrowing of the 35-cM interval in a previously described Cuban SCA2 family with a clinical picture similar to that of our family, including a high frequency of postural and action tremor.

Linkage of recessive familial amyotrophic lateral sclerosis to chromosome 2q33-q35

Amyotrophic lateral sclerosis (ALS) usually presents as a sporadic disorder of motor neurons. However, familial forms of ALS have been described--autosomal dominant forms (ALS1, ALS3), clinically indistinguishable from the sporadic form, and autosomal recessive forms with early onset and slower progression of symptoms (ALS2). To localize the gene for one of the autosomal recessive forms of ALS, we applied linkage analysis to a large inbred family from Tunisia. A lod score maximum of Zmax = 8.2 at theta = 0.00 was obtained with marker D2S72 located on chromosome 2q33-q35. The fine mapping of this region suggested that the ALS2 locus lies in the 8 cM segment flanked by D2S155 and D2S115.

Expression of myosin isoforms and of desmin, vimentin and titin in Tunisian Duchenne-like autosomal recessive muscular dystrophy

Morphological, morphometrical, histoenzymological, immunocytochemical and biochemical analysis were performed on muscle biopsies taken from patients suffering from tunisian autosomal recessive Duchenne-like muscular dystrophy (TDLMD) selected both by Duchenne-like clinical criteria and by the presence of normal dystrophin. Data were compared to that obtained from DMD biopsies characterized by the absence of dystrophin. The distribution of myosin heavy chain isoforms, desmin, vimentin and titin were determined in type I and type II muscle fibers. The protein pattern appeared to be less affected in TDLMD than in DMD biopsies. The regenerating fibers were mainly but not exclusively type IIC; a noticeable percentage of both type I and type II fibers coexpressed fast and slow MHC isoforms in TDLMD. This percentage was lower than in DMD. The expression of embryonic, fetal, and fast/slow myosin isoforms in type IIC fibers in TDLMD and DMD suggest different fiber type transformations in these two diseases.

Biochemical and immunocytochemical analysis in chronic proximal spinal muscular atrophy

Immunocytochemical and biochemical analyses were carried out on patients affected by chronic SMA. Three groups of patients were identified. In group I, the muscle presented a fascicular atrophy; a high percentage of atrophic type II fibers; and fibers expressing fast, slow, embryonic, and fetal myosin isoforms. In group II, the muscle was characterized by atrophic fibers and normal/hypertrophic fibers expressing only slow myosin isoforms. In group III, the muscle was characterized by fiber type grouping and fibers coexpressing fast and slow myosin isoforms but never embryonic or fetal MHC isoforms. The muscles of groups I and III contained both fast and slow myosins whereas group II muscles were predominantly slow by immunocytochemical analysis or only slow by biochemical analysis. In view of these results, immunocytochemical and histochemical analyses could help to classify chronic SMA and help to understand the different pathogenic processes which seem to be related to the maturational stage of the muscle at the age of onset of the disease.

Friedreich's ataxia phenotype not linked to chromosome 9 and associated with selective autosomal recessive vitamin E deficiency in two inbred Tunisian families

Friedreich's ataxia (FA) is an autosomal recessive neurodegenerative disorder, the disease locus (FRDA) of which has been assigned to 9q13-q21.1 by genetic linkage analysis in affected families. We report two large inbred Tunisian families with FA manifestations that did not show the expected linkage. The disease locus could be excluded from a large (12 cMo) region around FRDA. This is the first report providing evidence for nonallelic genetic heterogeneity for the FA clinical phenotype. On subsequent analysis, all patients had very low levels of serum vitamin E whereas the parents and healthy sibs had normal vitamin E levels. This establishes that the selective vitamin E deficiency with normal fat absorption is an autosomal recessive trait, which is associated in the two families reported here with the FA phenotype.

Linkage of a locus (CMT4A) for autosomal recessive Charcot-Marie-Tooth disease to chromosome 8q

Autosomal recessive Charcot-Marie-Tooth (CMT) disease (CMT4) is a complex group of severe childhood motor and sensory neuropathies, characterized by an early age of onset with rapidly progressive distal limb weakness and atrophy. One subgroup designated CMT4 type A (CMT4A) was selected from a series of Tunisian CMT4 families according to the following electrophysiological and pathological criteria: slow motor nerve conduction velocity (MCV), severe hypomyelination upon nerve biopsy with basal lamina onion bulbs and no myelin outfolding. In an attempt to localize the CMT4A locus, we studied four inbred families with 13 affected patients. Significant evidence for linkage was found for several markers from chromosome 8q13-21.1 (D8S279, D8S164, D8S286, D8S84, D8S275 and D8S167). An overall two point peak lod score of z(theta) = 9.19 at theta = 0.00 (95% confidence limit 0.00-0.08) was obtained for D8S164. No evidence of genetic heterogeneity was found. The chromosomal localization of one form of CMT4 will have important implications in clarifying the nosology of this complex group of disorders.

Localization of Friedreich ataxia phenotype with selective vitamin E deficiency to chromosome 8q by homozygosity mapping

Friedreich ataxia and ataxia with selective vitamin E deficiency (AVED) share very similar clinical phenotypes. We have mapped the AVED locus to proximal 8q with only three large consanguinous Tunisian families, representing to our knowledge the first use of homozygosity mapping for primary linkage analysis. Subsequently, three additional families showed linkage with the same markers. A maximum lod score of 17.9 was obtained at theta = 0 for the haplotype D8S260-D8S510, consisting of the two closest markers. With only 6 families, the AVED locus is therefore mapped precisely as illustrated by the lod-1 confidence interval of 2.4 cM on either side of D8S260-D8S510. Isolation of a yeast artificial chromosome contig > 800 kilobases (kb) showed that D8S260 and D8S510 are less than 400 kb apart.

Linkage of Tunisian autosomal recessive Duchenne-like muscular dystrophy to the pericentromeric region of chromosome 13q

Autosomal recessive Duchenne-like muscular dystrophy (DLMD) is a severe dystrophic myopathy. The incidence is unknown because of its clinical similarity to Duchenne muscular dystrophy (DMD). Three highly inbred DLMD families from Tunisia were analysed for chromosomal linkage using 135 polymorphic microsatellite markers. A significant lod score of z = 9.15 at theta = 0.03 was found with the 13q12 locus D13S115. Two additional 13q12 markers, D13S143 and D13S120, also gave significant lod scores. Therefore, the primary DLMD defect gene lies in the pericentrometric region of chromosome 13q.