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C Ozdemir

Publications and source records attributed to C Ozdemir.

At least 37 records · Page 2Linked to original sources
PubMed2000

Deletion pattern in the dystrophin gene in Turks and a comparison with Europeans and Indians.

Patterns of dystrophin gene deletions in DMD/BMD patients were compared in four populations: Turks (n = 146 deletions), Europeans (n = 838), North Indians (n = 89), and Indians from all over India (n = 103). Statistical tests revealed that there are differences in the proportions of small deletions. In contrast, the distribution of deletion breakpoints and the frequencies of specific deletions commonly observed in the four populations are not significantly different. The variations strongly suggest that sequence differences exist in the introns, and the differences are in agreement with genetic distances among populations. The similarities suggest that some intronic sequences have been conserved and that those will trigger recurrent deletions, since it is unlikely that gene flow would disperse the deleted chromosomes, which vanish from the gene pool in a few generations.

DNA Mutational Analysis↗
PubMed1999

Chromosome 17p-linked myasthenias stem from defects in the acetylcholine receptor epsilon-subunit gene.

OBJECTIVE: To identify and to characterize functionally the mutational basis of congenital myasthenic syndromes (CMS) linked to chromosome 17p. BACKGROUND: A total of 37 patients belonging to 13 CMS families, 9 of them consanguineous, were investigated. All patients were linked previously to the telomeric region of chromosome 17p. Two candidate genes in this region encode synaptobrevin 2, a presynaptic protein, and the epsilon-subunit of the acetylcholine receptor (AChR). Direct sequencing of the synaptobrevin 2 gene revealed no mutations. The authors thus searched for mutations in the epsilon-subunit gene of AChR. METHODS: Direct sequencing of the AChR epsilon-subunit, restriction analysis, allele-specific PCR, and expression studies in human embryonic kidney cells were performed. RESULTS: The authors identified two previously characterized and five novel epsilon-subunit gene mutations, all homozygous, in the 13 kinships. Two of the novel mutations are truncating (epsilon723delC and epsilon760ins8), one is a missense mutation in the signal peptide region (epsilonV-13D), one is a missense mutation in the N-terminal extracellular domain (epsilonT51P), and one is a splice donor site mutation in intron 10 (epsilonIVS10+2T-->G). Unaffected family members have no mutations or are heterozygous. Expression studies indicate that the four novel mutations in the coding region of the gene and the most likely transcript of the splice-site mutation, which skips exon 10, are low-expressor or null mutations. CONCLUSIONS: Chromosome 17p-linked congenital myasthenic syndromes are caused by low-expressor/null mutations in the AChR epsilon-subunit gene. Mutations in this gene are a common cause of CMS in eastern Mediterranean countries.

Adolescent↗
PubMed1999

Electrical myotonia in heterozygous carriers of recessive myotonia congenita.

We investigated electrophysiologically the unaffected parents of patients with recessive myotonia congenita. We studied 18 families, in nine of which the diagnosis was confirmed by molecular genetics. Brief myotonic discharges were present in at least one parent in 67% of the families. Fathers were more likely than mothers to show these discharges. The difficulty in distinguishing very mildly affected parents with dominant myotonia congenita from the heterozygous carriers of recessive myotonia congenita is stressed.

Action Potentials↗
PubMed1998

The use of botulinum toxin in localizing neuromyotonia to the terminal branches of the peripheral nerve.

In 2 patients with neuromyotonia, nerve blocks had no effect on the abnormal activity, while intramuscular injection of the botulinum toxin abolished the discharges in one and greatly diminished them in the other. Botulinum toxin thus helps to localize the origin of the neuromyotonic discharges to the terminal regions of the peripheral nerve in those cases where the more proximal portions cannot be held responsible.

Adult↗
PubMed1998

The dominant chloride channel mutant G200R causing fluctuating myotonia: clinical findings, electrophysiology, and channel pathology.

Clinical, electrophysiological, and molecular findings are reported for a family with dominant myotonia congenita in which all affected members have experienced long-term fluctuations of the symptom of myotonia. In some patients myotonia is combined with myalgia. The myotonia-causing mutation in this family is in the gene encoding the muscular chloride channel, hCIC-1, predicting the amino acid exchange G200R. We have constructed recombinant DNA vectors for expression of the mutant protein in tsA201 cells and investigation of the properties of the mutant channel. The most prominent alteration was a +100-mV shift of the midpoint of the activation curve. Therefore, within the physiological range the open probability of the mutant channel is markedly smaller than in wild-type. This shift is likely to be responsible for the myotonia in the patients. The fluctuating symptoms of this chloride channelopathy are discussed with respect to short-term fluctuations of myotonia in the sodium channelopathy of potassium-aggravated myotonia.

Adolescent↗
PubMed1998

Transient weakness and compound muscle action potential decrement in myotonia congenita.

Twenty-five Turkish patients with recessive myotonia congenita (RMC), 16 of whom had genetic confirmation, were studied. Nineteen had transient weakness. In the upper extremities, onset age of transient weakness was usually in the early teens. All untreated RMC patients had a compound muscle action potential decrement of > or =25%, usually above 50%, with repetitive nerve stimulation at 10/s for 5 s. Patients with other nondystrophic diseases with myotonia, except 1 patient with dominant myotonia congenita, had no transient weakness and a CMAP decrement below 25%.

Action Potentials↗
PubMed1997

The fate of alloplastic materials placed under a burn scar: an experimental study.

The behavior, under burn scars, of three different alloplastic materials, silicone, Medpor and Proplast, was compared in an animal model. A standard burn wound was created in rats, and 3 months later silicone, medpor and proplast alloplasts were placed under the burn scar. The rats were followed for another 3 months and ulceration and/or alloplast exposure rates were evaluated. At the end of this period specimens were examined histologically for the thickness of the fibrous capsule around the implant, thickness of the overlying tissue, tissue ingrowth and vascularization of the implants. Ulceration and exposure occurred in 2 of the 12 Medpor, 2 of the 12 Proplast and none of the 12 silicone implants. Fibrous capsule was significantly thicker around the silicone implants. Tissue ingrowth and vascularization were most prominent in Medpor implants while thickness of the overlying tissue was maximum in Proplast implants. These findings suggest that complications with silicone implants may be less than with other porous implants when used under burn scarred tissue.

Analysis of Variance↗
PubMed1997

Segmental distribution of muscle weakness in SMA III: implications for deterioration in muscle strength with time.

We examined 26 spinal muscular atrophy type III (SMA III) patients with SMNt deletions, searching for possible segmental distribution of muscle weakness. In those with disease duration of < or = 11 years, the weakest muscles were upper lumbar innervated ones in the lower extremities. In the upper extremities, early involvement of triceps muscle suggested the possibility of lower cervical (C7) onset. Electrophysiologically, weaker muscles had a more severe reduction in the recruitment pattern, particularly in the lower extremities. However, severe reduction in recruitment was sometimes also observed in clinically strong muscles. In patients with disease duration of > or = 16 years and regardless of disease duration, in those with disease onset at < or = 3 years of age, weakness and severe electrophysiological changes were more widespread. These findings may suggest a progression in muscle weakness with time. When compared to 12 patients with Becker muscular dystrophy (BMD), early stage SMA III with weak iliopsoas-strong gluteus maximus stood in contrast to BMD with weak gluteus maximus-strong iliopsoas.

Adolescent↗
PubMed1997

Mapping of the familial infantile myasthenia (congenital myasthenic syndrome type Ia) gene to chromosome 17p with evidence of genetic homogeneity.

Familial infantile myasthenia is an autosomal recessive disorder, recently classified as congenital myasthenic syndrome type Ia. Onset of symptoms is at birth to early childhood with significant myasthenic weakness and possible respiratory distress, followed later in life by symptoms of mild to moderate myasthenia. Thirty-six patients of 12 families, seven of them consanguineous, were used to map the familial infantile myasthenia gene. A combination of linkage search through the genome, DNA pooling and homozygosity mapping were employed resulting in the localisation of this disease locus to the telomeric region of chromosome 17p. A maximum lod score of 9.28 at theta = 0.034 was obtained between the disease locus and marker locus D17S1537. Haplotype analysis showed all families to be consistent with linkage to this region thus providing evidence for genetic homogeneity of familial infantile myasthenia. Multipoint linkage analysis mapped the disease gene in the approximately 4.0 cM interval between marker loci D17S1537 and D17S1298 with a maximum multipoint lod score of 12.07. Haplotype analysis and homozygosity by descent in affected individuals of the consanguineous families revealed results in agreement with the confinement of the familial infantile myasthenia region within the interval between marker loci D17S1537 and D17S1298.

Chromosome Mapping↗
PubMed1994

Andersen's syndrome: potassium-sensitive periodic paralysis, ventricular ectopy, and dysmorphic features.

Andersen's syndrome is a clinically distinct form of potassium-sensitive periodic paralysis associated with cardiac dysrhythmias. The subtle nature of the cardiac and dysmorphic features may delay the recognition of this syndrome and its potentially lethal cardiac dysrhythmias. The genetic defect in Andersen's syndrome is not genetically linked to other forms of potassium-sensitive periodic paralysis and is probably distinct from the long QT syndrome locus.

Abnormalities, Multiple↗
PubMed1993

Emery-Dreifuss muscular dystrophy with unusual features.

Two families with Emery-Dreifuss muscular dystrophy (EMD) are described. Several unusual features for EMD are emphasized. One of the patients had severe neuromuscular disability with inability to walk during early childhood. This patient also had mild bifacial paresis. His brothers had the typical slow progression of EMD. In some of the patients, muscle weakness distribution was more widespread than has usually been reported, with prominent involvement of finger extensors. It is suggested that there is a wide phenotypic spectrum in EMD. In both families, the disease segregated with markers spanning the EMD locus in Xq28.

Adolescent↗
PubMed1992

DNA analysis in Turkish Duchenne/Becker muscular dystrophy families.

The molecular genetics of Duchenne/Becker muscular dystrophy was investigated in 81 affected Turkish families. Deletions were detected by multiplex polymerase chain reaction assays and cDNA Southern analyses. The distribution of the deletions along the gene and their correlation to clinical phenotype were different from the studies reported on other populations. Moreover, DNA polymorphisms in mothers were determined using 8 DNA probes and three CA repeat sequences, and a high degree of informativeness was observed.

Chromosome Deletion↗
PubMed1989

Neurologic involvement in Behçet's syndrome. A prospective study.

We investigated the prevalence and type of neurologic involvement in Behçet's syndrome in a prospective protocol. Of 323 consecutive patients with Behçet's syndrome seen during a 12-month period, 46 underwent neurologic evaluation because of headaches and/or neurologic symptoms and signs. Only 17 (5.3%) were found to have involvement of the nervous system. Hemispheric lesions were as common as brain-stem involvement. Headaches were of no clinical importance unless accompanied by other neurologic findings. Computed tomographic scans were of little diagnostic help. After 12 +/- 4 (SD) months of follow-up, only three patients showed worsening of their neurologic findings.

Adult↗
PubMed1989

[The viral etiology of amyotrophic lateral sclerosis].

Roles of immunologic factors and slow virus infections in the aetiopathogenesis of amyotrophic lateral sclerosis (ALS) have recently gained significance. For this purpose, presence of poliovirus type I, measles and herpes simplex (HSV) type I antibodies were determined in the sera of ALS patients by complement fixation technique. Significant increase in antibody titers for poliovirus type I and HSV type I were determined in sera of ALS patients in comparison with controls and patients with other neurologic disorders.

Adult↗