C Transversion (c + transversion)

Distribution by Scientific Domains
Medical Sciences50%
Life Sciences50%

Selected Abstracts

Five novel inactivating mutations in the thyroid peroxidase gene responsible for congenital goiter and iodide organification defect,,

HUMAN MUTATION, Issue 3 2003
Carina M. Rivolta
Abstract Thyroid peroxidase (TPO) defects, typically transmitted as autosomal recessive traits, result in hypothyroid goiters with failure to convert iodide into organic iodine. We analyzed the TPO gene in 14 unrelated patients with clinical evidence of iodide organification defects. Seven of the affected individuals harbored mutations in the TPO gene; one was compound heterozygous, the others were simply heterozygous for TPO mutations. Five novel mutations have been identified, one of which was found to be a single nucleotide deletion, while the other four were single nucleotide substitutions. A frameshift mutation c.387delC was detected in exon 5 which leads to an early termination signal in exon 7 (p.N129fsX208). Two missense mutations were identified in exon 8. The first, a c.920A>C transversion that results in a p.N307T substitution, was found in two patients. The second, a c.1297G>A transition, results in p.V433M. A c.1496C>T transition was detected in exon 9 that caused the substitution p.P499L. Finally, in exon 14 a c.2422T>C transition was identified, causing a p.C808R change. In addition, the previously reported GGCC duplication in exon 8 (c.1186underscore;1187insGGCC; p.R396fsX472) was also detected in two affected individuals, one of whom was a compound heterozygous (p.R396fsX472/p.V433M). © 2003 Wiley-Liss, Inc. [source]

Mutations in the PAX9 gene in sporadic oligodontia

ORTHODONTICS & CRANIOFACIAL RESEARCH, Issue 3 2010
E Pawlowska
To cite this article: Pawlowska E, Janik-Papis K, Poplawski T, Blasiak J, Szczepanska J: Mutations in the PAX9 gene in sporadic oligodontia Orthod Craniofac Res 2010;13:142,152 Structured Abstract Authors,,, Pawlowska E, Janik-Papis K, Poplawski T, Blasiak J, Szczepanska J Objectives,,, Oligodontia, a congenital lack of six or more teeth, is often associated with mutations in the PAX9 gene; therefore, we searched for mutations in this gene. Design,,, In the present work, we sequenced fragments of the PAX9 gene in individuals with sporadic oligodontia. Next, we genotyped some mutations we found in patients with oligodontia and individuals without tooth agenesis. Setting and Sample Population,,, DNA sequencing was performed in the material isolated from peripheral blood lymphocytes of six unrelated patients with sporadic, non-syndromic oligodontia. These patients were selected based upon explorative cluster analysis. Genotyping was performed in 38 patients with oligodontia and 100 control individuals. Material and Methods,,, Direct sequencing and restriction fragment length polymorphism PCR were employed. Results,,, We detected two homozygotic substitutions, IVS2-109G>C and IVS2-54A>G, in intron 2 in three patients. Another homozygotic substitution in intron 2, IVS2-41A>G, was revealed in two patients. Two patients had an IVS3+40G>A homozygotic change in intron 3 and 4 patients displayed a 717C>T transition in exon 4 (silent mutation). One patient had a heterozygotic 718G>C transversion, resulting in a missense Ala240Pro substitution. We detected also several other intronic substitutions. Further genotyping of the IVS2-54A>G, IVS2-109G>C, and IVS2-41A>G mutations suggested that they can display polymorphic changes. Conclusion,,, The IVS2-54A>G, IVS2-109G>C, and IVS2-41A>G mutations of the PAX9 gene may represent polymorphism associated with sporadic oligodontia. [source]

Nijmegen breakage syndrome gene (NBS1) alterations and its protein (nibrin) expression in human ovarian tumours

ANNALS OF HUMAN GENETICS, Issue 5-6 2002
J. PLISIECKA-HA
We looked for NBS1 gene (602667) alterations and changes in nibrin expression in 162 human gynaecological tumours, mostly ovarian. Exons 6,8 and 10 of the NBS1 gene were evaluated by the SSCP and direct sequencing method. Nibrin expression was detected immunohistochemically with the use of the p95NBS1 (Ab-1) antibody. The 657del5 mutation (Slavic mutation) was found in two of 117 carcinomas studied (1.7%) , in both cases it was present in the germline; one of these tumours showed loss of heterozygosity (LOH) for the 657del5 mutation and loss of nibrin expression. We have found three types of novel germline intron variants: (1) two concomitant transitions (G to A) at bases 14009 and 14256; (2) C to T transition at base 13998; (3) G to C transversion at base 20035. Among the carcinomas studied, the intron variants were associated with a clear cell histological type (p = 0.004). Our results may suggest that NBS1 gene alterations contribute to the development of rare ovarian carcinomas. LOH for 657del5 in tumour tissue may support the hypothesis that the NBS1 gene functions as a tumour suppressor. [source]

Is the mitochondrial complex I ND5 gene a hot-spot for MELAS causing mutations?

ANNALS OF NEUROLOGY, Issue 1 2003
Danae Liolitsa PhD
We identified two novel heteroplasmic mitochondrial DNA point mutations in the gene encoding the ND5 subunit of complex I: a 12770A,G transition identified in a patient with MELAS (mitochondrial encephalomyopathy with lactic acidosis and stroke-like episodes) and a 13045A,C transversion in a patient with a MELAS/Leber's hereditary optic neuropathy/Leigh's overlap syndrome. Biochemical analysis of muscle homogenates showed normal or very mildly reduced complex I activity. Histochemistry was normal. Our observations add to the evidence that mitochondrial ND5 protein coding gene mutations frequently associate with the MELAS phenotype, and it highlights the role of complex I dysfunction in MELAS. Ann Neurol 2003 [source]