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Biomedical subjects

M Kefi

Publications and source records attributed to M Kefi.

11 recordsLinked to original sources

Genetic heterogeneity within a consanguineous family involving the LGMD 2D and the LGMD 2C genes.

The sarcoglycanopathies are a group of autosomal recessive limb girdle muscular dystrophies (AR-LGMD 2) characterised by mutations in gene encoding one of the sarcoglycan subunits. Mutations in SGCA, SGCB, SGCG and SGCD genes are associated with LGMD 2D, 2E, 2C and 2F, respectively. We report three Tunisian patients belonging to the same consanguineous family sharing similar LGMD 2 phenotype but heterogeneous sarcoglycans immunohistochemical patterns. Linkage analysis suggests linkage with the LGMD 2D locus for the two siblings and with LGMD 2C locus for the third patient. Mutation analysis revealed two distinct mutations. A del521T homozygous mutation in exon 6 of the SGCG gene (LGMD 2C), widely distributed in Tunisian patients, was found in one patient, whereas a 157G>A homozygous mutation in exon 2 of the SGCA gene (LGMD 2D) was found in the two siblings. The presence of two distinct genetic forms, LGMD 2C and LGMD 2D in a consanguineous family raises the problem of the complexity of genetic counselling in inbred populations.

Adult↗

Allelic heterogeneity of GNE gene mutation in two Tunisian families with autosomal recessive inclusion body myopathy.

Autosomal recessive hereditary inclusion body myopathy (AR-HIBM), with sparing of the quadriceps, is characterized by adult-onset, with weakness and atrophy of distal lower limb muscles, and typical histopathological findings in muscle biopsy. AR hIBM is associated with mutations in the UDP-N-acetylglucosamine 2-epimerase/N-acetylmannosamine kinase (GNE) gene on chromosome 9p12-13 . We report two unrelated Tunisian families with clinical and pathological features of AR HIBM. One distinct homozygous GNE missense mutation, M712T, previously reported in Middle Eastern Jewish patients, and a newly identified one, L379H, were found in one patient from each family. We conclude that AR HIBM in Tunisia shows an allelic genetic heterogeneity.

Adult↗

Aprataxin gene mutations in Tunisian families.

The authors report clinical and genetic study of 13 patients from three unrelated Tunisian families with an early onset cerebellar ataxia associated with oculomotor apraxia. Cerebellar ataxia with oculomotor apraxia 1 (AOA1) represents a clinically heterogeneous disease caused by mutations in the aprataxin gene. Two novel mutations were identified, the complete deletion of the gene, which seems to not correlate with an increased severity of the disease, and a splice mutation on the acceptor splice site of exon 7.

Adolescent↗

[Lateral gaze palsy and progressive scoliosis in 4 Tunisian families].

In 1975, Sharpe and Silversides described a neurological entity in a Chinese family. Clinical picture was characterized by paralysis of horizontal gaze, pendular nystagmus and progressive scoliosis. To date, 43 cases have been reported. The pathogenesis remains unclear. The Authors report four Tunisian families with 12 affected individuals. The age of patients ranges from 6 to 34 Years. All examined patients have complete lateral gaze palsy, pendular nystagmus and progressive scoliosis. Blood routine tests, cerebrospinal fluid (CSF), evoked potentials, electromyography (EMG), muscle biopsy, CT scan and cerebral MRI were normal. Autosomal recessive (AR) mode of inheritance is the most probable pattern.

Adolescent↗

Fukutin-related protein gene mutated in the original kindred limb-girdle MD 2I.

The authors mapped an autosomal recessive form of limb-girdle MD on chromosome 19q13.3 (LGMD2I), further narrowed down the candidate region to 1.1 Mb, and identified one new homozygous mutation in the fukutin-related protein (FKRP) gene on patients of the original Tunisian family. Immunohistochemical and immunoblot analysis showed abnormal expression of alpha-dystroglycan and laminin-alpha2 supporting the hypothesis that FKRP has a role in the interaction between the extracellular matrix components.

Amino Acid Substitution↗

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.

Adolescent↗

Effect of vitamin E supplementation in patients with ataxia with vitamin E deficiency.

Ataxia with vitamin E (Vit E) defciency (AVED) is an autosomal recessive disorder caused by mutations of the alpha tocopherol transfer protein gene. The Friedreich ataxia phenotype is the most frequent clinical presentation. In AVED patients, serum Vit E levels are very low in the absence of intestinal malabsorption. As Vit E is a major antioxidant agent, Vit E deficiency is supposed to be responsible for the pathological process. Twenty-four AVED patients were fully investigated (electromyography, nerve conduction velocity (NVC) studies, somatosensory evoked potentials, cerebral computed tomography scan, sural nerve biopsy, genetic studies) and supplemented with Vit E (800 mg daily) during a 1-year period. Clinical evaluation was mainly based on the Ataxia Rating Scale (ARS) for cerebellar ataxia assessment and serum Vit E levels were monitored. Serum Vit E levels normalized and ARS scores decreased moderately but significantly suggesting clinical improvement. Better results were noted with mean disease duration < or = 15 years. Reflexes remained abolished and posterior column disturbances unchanged. Vitamin E supplementation in AVED patients stabilizes the neurological signs and can lead to mild improvement of cerebellar ataxia, especially in early stages of the disease.

Adult↗