[Study of correlation between radiological aspect of pulmonary hydatid cyst and postoperative course]. / Étude de corrélation entre les aspects radiologiques des kystes hydatiques pulmonaires et les suites opératoires.

Pulmonary Hydatid Cyst (PHC) may represent a real therapeutic challenge. Surgery remains the treatment of choice and postoperative course may be complicated in some cases. Several factors can be involved like the cyst's size and location. We aimed to study the existence of correlation between the radiological aspect of the PHC and the postoperative course through a retrospective study including 267 patients. Different radiological aspect of PHC found on the X-ray and/or computed tomography of the chest were classified according to Zidi et al. CLASSIFICATION: Analytical study showed that there is minor chance to have complications with simple cyst (P<0.05 and OR<1), while type VI cyst were more likely to cause complications (P=0.007 and OR=2.6). Considering these results, more attention should be paid to type VI of PHC to prevent postoperative complications. A multicentric study will be more precise to study correlation between different characteristics of the PHC and postoperative course.

[Hydatid cysts of the liver ruptured into the thorax (about five cases)]. / Kystes hydatiques du foie rompus dans le thorax (à propos de cinq cas).

INTRODUCTION: Hydatid cyst of the liver remains a serious public health problem in Tunisia. This benign affection can sometimes cause fatal complications such as cyst rupture into the thorax. CLINICAL CASES: We report 5 cases of patients who experienced intrathoracic rupture of hydatic cyst of liver. There were four rural women and an urban man. Patients were between 60 and 75 years of age. We present 2 cases of cyst rupture into pleura, 3 cases of hydatid bronchial fistula and 3 cases of biliothoracic fistulas. Surgical treatment was performed by laparotomy in 3 cases, thoracic approach in one case and by thoracoabdominal approach in the other case. We deplore one case of early death by hemorrhagic shock. CONCLUSION: Authors emphasize the complexity of the management of hydatic cyst of liver ruptured into the thorax. Surgical treatment remains responsible of high perioperative morbidity and mortality. Early diagnostic and improvement of reanimation measures are important to improve the prognosis of this serious complication.

[Spontaneous regression of epithelial thymic tumours]. / Tumeurs épithéliales thymiques de régression spontanée.

INTRODUCTION: Spontaneous regression of an epithelial thymic tumour has been reported but seems extremely rare. Its mechanism is unknown. CASE REPORT: We report two cases of epithelial thymic tumour, either histologically proven or highly suspected on imaging, that regressed spontaneously (partially in one patient and totally in the other). CONCLUSION: Spontaneous regression of an epithelial thymic tumour is very rare but this possibility could lead to clinical and radiological monitoring rather than surgery in selected patients.

The gene encoding alsin, a protein with three guanine-nucleotide exchange factor domains, is mutated in a form of recessive amyotrophic lateral sclerosis.

Amyotrophic lateral sclerosis (ALS) and primary lateral sclerosis (PLS) are neurodegenerative conditions that affect large motor neurons of the central nervous system. We have identified a familial juvenile PLS (JPLS) locus overlapping the previously identified ALS2 locus on chromosome 2q33. We report two deletion mutations in a new gene that are found both in individuals with ALS2 and those with JPLS, indicating that these conditions have a common genetic origin. The predicted sequence of the protein (alsin) may indicate a mechanism for motor-neuron degeneration, as it may include several cell-signaling motifs with known functions, including three associated with guanine-nucleotide exchange factors for GTPases (GEFs).

Novel mutations in spastin gene and absence of correlation with age at onset of symptoms.

Autosomal dominant hereditary spastic paraplegia is genetically heterogeneous, with at least five loci identified by linkage analysis. Recently, mutations in spastin were identified in SPG4, the most common locus for dominant hereditary spastic paraplegia that was previously mapped to chromosome 2p22. We identified five novel mutations in the spastin gene in five families with SPG4 mutations from North America and Tunisia and showed the absence of correlation between the predicted mutant spastin protein and age at onset of symptoms.

Linkage of a commoner form of recessive amyotrophic lateral sclerosis to chromosome 15q15-q22 markers.

Autosomal recessive familial amyotrophic lateral sclerosis (RFALS) is a rare form of ALS that usually presents at an early age with slow progression of symptoms. RFALS is clinically and genetically heterogeneous and the locus of RFALS type 3 was mapped to 2q33 (ALS2) in a single family. We now report linkage of a more-common form of RFALS to chromosome 15q15-q22 markers (ALS5) and show further genetic locus heterogeneity in RFALS. ALS5 is the locus for most families with RFALS and appears to be present in both North African and European populations.

A novel mutation in the sterol 27-hydroxylase gene of a Pakistani family with autosomal recessive cerebrotendinous xanthomatosis.

Cerebrotendinous xanthomatosis (CTX) is a rare autosomal recessive disorder of lipid storage with prominent neurologic features. The disease is associated with mutations in CYP27, which encodes mitochondrial sterol 27-hydroxylase, an enzyme that catalyzes the oxidation of sterol intermediates during bile acid synthesis. The loss of this enzyme results in accumulation of cholestanol in the nervous system and other tissues. Six different mutations have been previously described in CTX. We analyzed a Pakistani family, which included four affected individuals with clinical characteristics of CTX, for mutations in CYP27. The exons of CYP27 in the family DNA were amplified by polymerase chain reaction (PCR) and analyzed for mutations by band shifts (single stranded conformational polymorphism [SSCP]) and DNA sequencing. The PCR product for exon 4 showed an SSCP change in this family. The DNA of affected individuals showed an abnormal mobility pattern interpreted as homozygous for the mutation. One non-affected sibling was homozygous for the normal migrating pattern, whereas the parents and another non-affected sibling were heterozygous. The sequence of exon 4 of affected individuals showed a substitution of C to T in codon 237, thus substituting arginine to a stop codon. This mutation would terminate the translation, which may result in a protein half the size of the wild type rendering it practically inactive.

Familial amyotrophic lateral sclerosis.

Amyotrophic lateral sclerosis is sporadic in ninety percent of cases and familial (FALS) in ten percent. Both forms of FALS whether transmitted as an autosomal dominant (DFALS) or as an autosomal recessive (RFALS) trait is genetically heterogeneous. The locus for one form of RFALS maps to chromosome 2q33. Fifteen percent of DFALS families have mutations in the gene for Cu, Zn superoxide dismutase (SOD1) gene which is coded on chromosome 21. These mutations result in decreased SOD1 activity and shortened half-life of the protein in most instances. Transgenic mice overexpressing mutated SOD1 protein develop an ALS-like disease which suggests that the degeneration of motor neurons in DFALS is caused by the gain of a novel toxic function by mutated SOD1 rather than by the decrease of SOD1 activity. Possible mechanisms of the novel neurotoxic function of mutated SOD1 are discussed.

Molecular genetic basis of familial ALS.

Familial amytrophic lateral sclerosis (FALS) is transmitted in a mendelian fashion as an autosomal dominant (DFALS) or an autosomal recessive (RFALS) trait. Both DFALS and RFALS are genetically heterogeneous. Fifteen percent of DFALS families have mutations in the gene for Cu, Zn superoxide dismutase (SOD1) which is coded on chromosome 21. The locus for one form of RFALS maps to chromosome 2q33. Forty-six mutations in the SOD1 gene have been reported in DFALS families. These mutations result in decreased SOD1 activity and shortened half-life of the protein in most instances. Transgenic mice overexpressing mutated SOD1 protein develop an ALS-like disease which suggests that the degeneration of motor neurons in DFALS is caused by the gain of a novel toxic function by mutated SOD1 rather than by the decrease of SOD1 activity. Several possible mechanisms of the novel neurotoxic function of mutated SOD1 are discussed.

Linkage of scapuloperoneal spinal muscular atrophy to chromosome 12q24.1-q24.31.

Scapuloperoneal (SP) syndromes are heterogeneous neuromuscular disorders which are characterized by weakness in the distribution of shoulder girdle and peroneal muscles. SP syndromes can resemble facioscapulohumeral muscular dystrophy (FSH) due to scapular weakness or Charcot-Marie-Tooth disease (CMT) due to atrophy of peroneal muscles. Both neurogenic and myopathic SP syndromes have been described. Locus for the myopathic form of SP syndrome (scapuloperoneal muscular dystrophy, SPMD) has recently been assigned to chromosome 12q. We previously described a large New England kindred exhibiting an autosomal dominant neurogenic SP syndrome (scapuloperoneal spinal muscular atrophy, SPSMA). Disease expression was more severe and progressive in successive generations, which suggested genetic anticipation. We performed genetic linkage analysis of this family with microsatellite markers and excluded the loci for FSH, CMT, SPMD and SMA (spinal muscular atrophy) in our family. Linkage in our SPSMA family (lod score > 3) was established to seven microsatellite markers that map to chromosome 12q24.1-q24.31. The highest lod score with two-point linkage analysis was 6.67 (theta = 0.00) with marker D12S353. Multipoint analysis gave maximum lod scores of 7.38 between D12S354 and D12S79, and also 7.38 between D12S369 and NOS1 (neuronal nitric oxide synthase). The gene for SPSMA lies within the 19 cM interval between D12S338 and D12S366. This report establishes a locus for the neurogenic form of SP syndrome approximately 20 cM telomeric to the one described for the myopathic form of SP syndrome.

Hereditary spastic paraplegia: advances in genetic research. Hereditary Spastic Paraplegia Working group.

Hereditary spastic paraplegia (HSP) is a diverse group of inherited disorders characterized by progressive lower-extremity spasticity and weakness. Insight into the genetic basis of these disorders is expanding rapidly. Uncomplicated autosomal dominant, autosomal recessive, and X-linked HSP are genetically heterogeneous: different genes cause clinically indistinguishable disorders. A locus for autosomal recessive HSP is on chromosome 8q. Loci for autosomal dominant HSP have been identified on chromosomes 2p, 14q, and 15q. One locus (Xq22) has been identified for X-linked, uncomplicated HSP and shown to be due to a proteolipoprotein gene mutation in one family. The existence of HSP families for whom these loci are excluded indicates the existence of additional, as yet unidentified HSP loci. There is marked clinical similarity among HSP families linked to each of these loci, suggesting that gene products from HSP loci may participate in a common biochemical cascade, which, if disturbed, results in axonal degeneration that is maximal at the ends of the longest CNS axons. Identifying the single gene defects that cause HSPs distal axonopathy may provide insight into factors responsible for development and maintenance of axonal integrity. We review clinical, genetic, and pathologic features of HSP and present differential diagnosis and diagnostic criteria of this important group of disorders. We discuss polymorphic microsatellite markers useful for genetic linkage analysis and genetic counseling in HSP.

Human alpha-tocopherol transfer protein: gene structure and mutations in familial vitamin E deficiency.

Familial vitamin E deficiency (AVED) causes ataxia and peripheral neuropathy that resembles Friedreich's ataxia. AVED is thought to be caused by a defect in the transport of vitamin E in liver cells, which is the probable function of alpha-tocopherol transfer protein (alphaTTP). We have cloned the cDNA and several genomic phage clones covering the entire human alphaTTP gene and determined the junctions between the five exons and four introns that composed the gene for human alphaTTP. Three mutations in three unrelated North American families with AVED were identified. Two mutations, 485delT and 513insTT, cause a frame shift and a premature stop codon and the third mutation 574G-->A would substitute Arg192 to His in alphaTTP. The 2 patients with a severe form of AVED were homozygous with 485delT and 513insTT, respectively, while the patient with a mild form of the disease was compound heterozygous with 513insTT and 574G-->A. These findings have identified the underlying genetic defect in AVED and have confirmed the role of alphaTTP in AVED.

Familial amyotrophic lateral sclerosis.

Amyotrophic lateral sclerosis (ALS) is inherited in ten percent of cases as a Mendelien trait. Familial ALS (FALS) is genetically heterogeneous and transmitted either as an autosomal dominant (DFALS) or an autosomal recessive (RFALS) trait. Fifteen percent of DFALS families have mutations in the gene for Cu,Zn superoxide dismutase (SOD1) which is coded on chromosome 21. These mutations result in decreased SOD1 activity and shortened half-life of the protein in most instances. Several observations suggest that the degeneration of motor neurons in DFALS is caused by the gain of a novel toxic function by mutated SOD1 rather than by the decrease of SOD1 activity. Possible mechanisms of the novel neurotoxic function of mutated SOD1 are discussed. The role of eventual neurofilament involvement in the pathogenesis of ALS is also discussed. The locus for one form of RFALS has been mapped to chromosome 2q33. FALS can also be associated with dementia and the gene locus for one form of hereditary ALS-dementia syndrome maps to chromosome 17q21-22.

Linkage of a locus for autosomal dominant familial spastic paraplegia to chromosome 2p markers.

'Pure' autosomal dominant familial spastic paraplegia (SPG) is a neurodegenerative disease which clinically manifests as spasticity of the lower limbs. Dominantly inherited SPG is known to be clinically heterogenous and has been classified into late-onset and early-onset types, based on the age of onset of symptoms. We tested five autosomal dominant SPG families for genetic linkage and established linkage to chromogene 2p markers (Z(theta) = 3.65) with evidence of genetic locus heterogeneity. Three late-onset SPG families and one early-onset SPG family had high posterior probability of linkage (P > 0.94) to chromosome 2p, while the fifth family (a very early-onset family) was not linked to chromosome 2 and showed high probability of linkage to chromosome 14q. These data provide a basis for a classification of SPG according to chromosome location rather than age of onset of symptoms.

Linkage of 'pure' autosomal recessive familial spastic paraplegia to chromosome 8 markers and evidence of genetic locus heterogeneity.

'Pure' familial spastic paraplegias (FSP) are neurodegenerative disorders that are clinically characterized by progressive spasticity of the lower limbs and are inherited as autosomal dominant (DFSP) or autosomal recessive (RFSP) traits. The primary defect in FSP is unknown. Genetic linkage analysis was applied to five RFSP families from Tunisia. In four of these five families tight linkage of the RFSP locus was established to the chromosome 8 markers, D8S260, D8S166, D8S285, PLAT, and D8S279. The RFSP locus in the fifth family was not linked to these markers which provided evidence of genetic locus heterogeneity in RFSP. Identification of the RFSP gene on chromosome 8 will help in understanding the genetic factors in motor neuron degeneration.

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.

Motor neuron degeneration in mice that express a human Cu,Zn superoxide dismutase mutation.

Mutations of human Cu,Zn superoxide dismutase (SOD) are found in about 20 percent of patients with familial amyotrophic lateral sclerosis (ALS). Expression of high levels of human SOD containing a substitution of glycine to alanine at position 93--a change that has little effect on enzyme activity--caused motor neuron disease in transgenic mice. The mice became paralyzed in one or more limbs as a result of motor neuron loss from the spinal cord and died by 5 to 6 months of age. The results show that dominant, gain-of-function mutations in SOD contribute to the pathogenesis of familial ALS.