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Biomedical subjects

F Hentati

Publications and source records attributed to F Hentati.

At least 73 records · Page 4Linked to original sources
PubMed1996

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.

Age of Onset↗
PubMed1995

Mutations in the dystrophin-associated protein gamma-sarcoglycan in chromosome 13 muscular dystrophy.

Severe childhood autosomal recessive muscular dystrophy (SCARMD) is a progressive muscle-wasting disorder common in North Africa that segregates with microsatellite markers at chromosome 13q12. Here, it is shown that a mutation in the gene encoding the 35-kilodalton dystrophin-associated glycoprotein, gamma-sarcoglycan, is likely to be the primary genetic defect in this disorder. The human gamma-sarcoglycan gene was mapped to chromosome 13q12, and deletions that alter its reading frame were identified in three families and one of four sporadic cases of SCARMD. These mutations not only affect gamma-sarcoglycan but also disrupt the integrity of the entire sarcoglycan complex.

Amino Acid Sequence↗
PubMed1995

Physical and genetic mapping of the CMT4A locus and exclusion of PMP-2 as the defect in CMT4A.

We have previously localized one form of the autosomal recessive Charcot-Marie-Tooth disease type 4 (CMT4A) to a 5-cM region of chromosome 8q13-q21. We now report the formation of a 7-Mb YAC contig spanning the region. This contig was used to map nine additional microsatellites and six STSs to this region, and subsequent haplotype analysis has narrowed the CMT4A flanking interval to less than 1 cM. In addition, using SSCP and our physical map, we have demonstrated that the myelin protein PMP-2, mapped by FISH to this region, is not the defect in CMT4A.

Adaptor Proteins, Signal Transducing↗
PubMed1995

Ataxia with isolated vitamin E deficiency is caused by mutations in the alpha-tocopherol transfer protein.

Ataxia with isolated vitamin E deficiency (AVED) is an autosomal recessive neurodegenerative disease which maps to chromosome 8q13. AVED patients have an impaired ability to incorporate alpha-tocopherol into lipoproteins secreted by the liver, a function putatively attributable to the alpha-tocopherol transfer protein (alpha-TTP). Here we report the identification of three frame-shift mutations in the alpha TTP gene. A 744delA mutation accounts for 68% of the mutant alleles in the 17 families analysed and appears to have spread in North Africa and Italy. This mutation correlates with a severe phenotype but alters only the C-terminal tenth of the protein. Two other mutations were found in single families. The finding of alpha TTP gene mutations in AVED patients substantiates the therapeutic role of vitamin E as a protective agent against neurological damage in this disease.

Africa, Northern↗
PubMed1995

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.

Adolescent↗
PubMed1995

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.

Child↗
PubMed1995

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.

Africa, Northern↗
PubMed1994

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.

Adolescent↗
PubMed1994

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.

Adolescent↗
PubMed1994

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.

Adolescent↗
PubMed1994

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.

Adolescent↗
PubMed1994

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.

Chromosome Mapping↗
PubMed1994

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.

Adolescent↗
PubMed1994

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.

Adult↗
PubMed1994

Phenotype and functional profile of T cells expressing gamma delta receptor from patients with active Behçet's disease.

OBJECTIVE: Our aim was to investigate the TCR gamma delta+ subset in Behçet's disease (BD) inflammatory sites, which better reflects changes associated with the pathologic process than peripheral blood. METHODS: Forty-five patients with active BD, 10 patients with recurrent aphthous ulcers, 12 patients with rheumatoid arthritis, 5 patients with noninflammatory neurologic diseases and 15 healthy individuals were studied. Three monoclonal antibodies TCR delta 1, BB3, and A13 were used to assess the percentage of TCR gamma delta+ in peripheral blood mononuclear cells (PBMC), in bronchoalveolar lavage and cerebrospinal fluid (CSF). CD11a/CD18 was used to study adhesion molecules. TCR gamma delta+ cells isolated by immunomagnetic separation were tested for cytolytic activity against K562 target cells after interleukin 2 stimulation. RESULTS: The PBMC TCR gamma delta BB3+ subset was significantly increased in BD. In BD inflammatory sites, TCR gamma delta+ cells were also present, composed mainly of A13+ cells from these sites also expressed CD11a marker. TCR gamma delta+ cells from inflammatory sites displayed a higher cytotoxic activity than controls, mediated by the A13+ subset. CONCLUSION: The accumulation of cytotoxic TCR gamma delta+ cells at the sites of inflammation suggests their involvement in the local injury process.

Adult↗