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At least 199 records · Page 11Linked to original sources
PubMed2000

Novel frameshift mutations in the RP2 gene and polymorphic variants.

Mutations in the RP2 gene located on Xp11.23 are associated with X-linked retinitis pigmentosa (XLRP), a severe form of progressive retinal degeneration which leads to complete loss of vision in affected males. To date, 14 different mutations in the RP2 gene have been reported to cause XLRP, the majority of which lead to a coding frameshift within the gene and predicted truncation of the protein product. We here report two novel frameshift mutations in RP2 identified in XLRP families by PCR-SSCP and direct sequencing, namely 723delT and 796-799del. Four single nucleotide polymorphisms (SNPs) within the coding region of RP2 are also described (105A>T, 597T>C, 844C>T, 1012G>T), the first polymorphisms to be reported within this gene of unknown function, two of which alter the amino acid sequence. The current study extends the XLRP mutation profile of RP2 and highlights non-pathogenic coding sequence variations which may facilitate both functional studies of the gene and analysis of intragenic allelic contribution to the phenotype.

Alternative Splicing↗
PubMed2001

Novel frameshift mutations in CRX associated with Leber congenital amaurosis.

Mutations in CRX, a photoreceptor-specific transcription factor, can cause Leber congenital amaurosis (LCA), cone-rod dystrophy (CORD), and retinitis pigmentosa (RP), all of which feature severe visual impairment. Upon screening 55 patients with Leber congenital amaurosis, 75 patients with cone-rod dystrophy, 13 with cone dystrophy, and 36 with recessive or isolate RP for changes in the CRX sequence, we found two patients with Leber congenital amaurosis who carried heterozygously one of two novel frameshift mutations. The first mutation, Tyr191(1-bp del), was a de novo change and the second change, Pro263(1-bp del) was inherited from the proband's affected father. Both mutations are predicted to encode mutant versions of CRX with altered carboxy termini. We also found a previously reported missense mutation, Arg41Gln, heterozygously in a 47-year-old patient with a form of RP. The missense change Val242Met was found in an isolate case of CORD and no controls; however, its pathogenicity remains uncertain because only limited segregation analysis was possible. A nonpathogenic missense change, Ala158Thr, was found to be a variant present at relatively high frequency among African-Americans.

DNA↗
PubMed1996

The defective secretion of a naturally occurring alpha-1-antichymotrypsin variant with a frameshift mutation.

A newly found variant alpha-1-antichymotrypsin (ACT), ACT Isehara-2, has a deletion of two bases (AA) at codon 391 near the carboxyl terminus. This frameshift mutation caused a change in the amino acid sequence and generated 10 extra amino acids (408 amino acids total) [Tsuda, M., Sei, Y., Matsumoto, M., Kamiguchi, H., Yamamoto, Y., Shinohara, Y., Igarashi, T. & Yamamura, M. (1992) Hum. Genet. 91. 467-468]. The serum ACT levels in three unrelated heterozygotes with this mutant ACT gene were 37% 49% and 54% that of the normal individuals. To examine the reduced serum levels, the normal ACT and the mutant ACT created by site-directed mutagenesis were transfected into COS-7 cells for comparison. The value for the retention rate (intracellular ACT/total ACT) was apparently higher in the cells expressing mutant ACT Isehara-2 than those bearing the normal gene. In the pulse-chase experiments, the secretion of the synthesized mutant ACT into the medium was not observed, whereas the normal ACT was mostly secreted as a 64-kDa form. The endoglycosidase H digestion and an electron microscopic analysis indicated that the retained mutant ACT was present in the endoplasmic reticulum. These results provide the biochemical basis for the decreased serum ACT level of individuals with ACT Isehara-2, and suggest the importance of the carboxyl-terminal region for its secretion.

Amino Acid Sequence↗
PubMed2001

A frameshift mutation in MC1R and a high frequency of somatic reversions cause black spotting in pigs.

Black spotting on a red or white background in pigs is determined by the E(P) allele at the MC1R/Extension locus. A previous comparison of partial MC1R sequences revealed that E(P) shares a missense mutation (D121N) with the E(D2) allele for dominant black color. Sequence analysis of the entire coding region now reveals a second mutation in the form of a 2-bp insertion at codon 23 (nt67insCC). This mutation expands a tract of six C nucleotides to eight and introduces a premature stop codon at position 56. This frameshift mutation is expected to cause a recessive red color, which was in fact observed in some breeds with the E(P) allele present (Tamworth and Hereford). RT-PCR analyses were conducted using skin samples taken from both spotted and background areas of spotted pigs. The background red area had transcript only from the mutant nt67insCC MC1R allele, whereas the black spot also contained a transcript without the 2-bp insertion. This indicates that black spots are due to somatic reversion events that restore the frame and MC1R function. The phenotypic expression of the E(P) allele is highly variable and the associated coat color ranges from red, red with black spots, white with black spots, to almost completely solid black. In several breeds of pigs the phenotypic manifestation of this allele has been modified by selection for or against black spots.

Alleles↗
PubMed1991

Adaptive reversion of a frameshift mutation in Escherichia coli.

Mutation rates are generally thought not to be influenced by selective forces. This doctrine rests on the results of certain classical studies of the mutations that make bacteria resistant to phages and antibiotics. We have studied a strain of Escherichia coli which constitutively expresses a lacI-lacZ fusion containing a frameshift mutation that renders it Lac-. Reversion to Lac+ is a rare event during exponential growth but occurs in stationary cultures when lactose is the only source of energy. No revertants accumulate in the absence of lactose, or in the presence of lactose if there is another, unfulfilled requirement for growth. The mechanism for such mutation in stationary phase is not known, but it requires some function of RecA which is apparently not required for mutation during exponential growth.

Adaptation, Biological↗
PubMed2003

[Suppression of nonsense and frameshift mutations obtained by different methods for inactivating the translation termination factor eRF3 in yeast Saccharomyces cerevisiae].

Mutations in genes of omnipotent nonsense suppressors SUP35 and SUP45 in yeast Saccharomyces cerevisiae encoding translation termination factors eRF3 and eRF1, respectively, and prionization of the eRF3 protein may lead to the suppression of some frameshift mutations (CPC mutations). Partial inactivation of the translation termination factor eRF3 was studied in strains with unstable genetically modified prions and also in transgenic yeast S. cerevisiae strains with the substitution of the indigenous SUP35 gene for its homolog from Pichia methanolica or for a recombinant S. cerevisiae SUP35 gene. It was shown that this partial inactivation leads not only to nonsense suppression, but also to suppression of the frameshift lys2-90 mutation. Possible reasons for the correlation between nonsense suppression and suppression of the CPC lys2-90 mutation and mechanisms responsible for the suppression of CPC mutations during inactivation of translation termination factors are discussed.

Codon, Nonsense↗
PubMed2005

Two novel frameshift mutations of the EBP gene in two unrelated Thai girls with Conradi-Hünermann-Happle syndrome.

Conradi-Hünermann-Happle syndrome, also known as X-linked dominant chondrodysplasia punctata (CDPX2), is characterized by skeletal abnormalities, cutaneous anomalies and cataracts. CDPX2 is caused by mutations in the emopamil-binding protein (EBP). We report two unrelated Thai female patients with clinically typical CDPX2, in which we discovered two novel and de novo frameshift mutations: 506-507delAG and 540-541delCC. This study demonstrates that EBP is the gene responsible for CDPX2 across different populations and extends the total number of confirmed mutations to 55.

Base Sequence↗
PubMed2006

MEN1 family with a novel frameshift mutation.

Multiple endocrine neoplasm type 1 (MEN1) syndrome predisposes to the development of endocrine and non-endocrine tumors with an autosomal dominant pattern of inheritance. Different mutations have been found throughout the gene with a variable phenotype expression. The proband, a Caucasian man, was admitted to our department in 2001, at the age of 51 because of a 1-yr history of diarrhoea and hypertension. He reported a previous intestinal resection for bowel occlusion with a histological diagnosis of unspecified mesenchymal neoplasia. He had also undergone a left adrenalectomy for a large nonfunctioning adrenal adenoma. Subsequently, he had suffered from gastralgia and melena; a gastroduodenoscopy showed an erosive gastritis. His family history was negative for endocrine disorders. On physical examination, multiple abdominal cutaneous lipomas and facial angiofibromas were observed. Biochemical screening revealed a primary hyperparathyroidism and an increase in circulating levels of PRL, chromogranin-A, gastrin and glucagon. The whole body computed tomography (CT) scan, the 111In-octreotide scan and the pituitary magnetic resonance imaging (MRI) did not reveal any abnormality. The presence of small neuroendocrine tumors was suspected by a positron emission tomography uptake in the epigastric region. The endoscopic ultrasound revealed a pancreatic lesion sized 1.1 cm that is under evaluation. Direct DNA sequencing analysis of the proband MEN1 gene revealed the 579delG frameshift mutation in the exon 3. The genetic screening of the family revealed the same mutation in 3 out of 5 offspring. The biochemical screening revealed some features of the MEN1 syndrome in all three of them. In conclusion, a novel frameshift MEN1 mutation was found in kindred with an apparently negative family history. Our experience confirms that MEN1 syndrome is a complex and underestimated condition, unless specifically investigated by trained specialists.

Adult↗
PubMed2000

Localized reversible frameshift mutation in the flhA gene confers phase variability to flagellin gene expression in Campylobacter coli.

Phase variation of flagellin gene expression in Campylobacter coli UA585 was correlated with high-frequency, reversible insertion and deletion frameshift mutations in a short homopolymeric tract of thymine residues located in the N-terminal coding region of the flhA gene. Mutation-based phase variation in flhA may generate functional diversity in the host and environment.

Bacterial Proteins↗
PubMed2005

The frameshift mutation in Nod2 results in unresponsiveness not only to Nod2- but also Nod1-activating peptidoglycan agonists.

NOD2/CARD15 is the first characterized susceptibility gene in Crohn disease. The Nod2 1007fs (Nod2fs) frameshift mutation is the most prevalent in Crohn disease patients. Muramyl dipeptide from bacterial peptidoglycan is the minimal motif detected by Nod2 but not by Nod2fs. Here we investigated the response of human peripheral blood mononuclear cells (PBMCs) from Crohn disease patients not only to muramyl dipeptide but also to several other muramyl peptides. Most unexpectedly, we observed that patients homozygous for the Nod2fs mutation were totally unresponsive to MurNAc-L-Ala-D-Glu-meso-diaminopimelic acid (DAP) (M-Tri(DAP)), the specific agonist of Nod1, and to Gram-negative bacterial peptidoglycan. In contrast, PBMCs from a patient homozygous for the Nod2 R702W mutation, also associated with Crohn disease, displayed normal response to Gram-negative bacterial peptidoglycan. In addition, the blockage of the Nod1/M-Tri(DAP) pathway could be partially overcome by co-stimulation with the Toll-like receptors agonists lipoteichoic acid or lipopolysaccharide. Investigation into the mechanism of this finding revealed that Nod2fs did not act as a dominant-negative molecule for the Nod1/M-Tri(DAP) pathway, implying that the blockage is dependent upon the expression or activity of other factors. We demonstrated that PBMCs from Nod2fs patients express high levels of the peptidoglycan recognition protein S, a secreted protein known to interact with muramyl peptides. We proposed that through a scavenger function, peptidoglycan recognition protein S may dampen M-Tri(DAP)-dependent responses in Nod2fs patients. Together, our results identified a cross-talk between the Nod1 and Nod2 pathways and suggested that down-regulation of Nod1/M-Tri(DAP) pathway may be associated with Crohn disease.

Acetylmuramyl-Alanyl-Isoglutamine↗
PubMed1999

New frameshift mutation in the 5alpha-reductase type 2 gene in a Brazilian patient with 5alpha-reductase deficiency.

Male pseudohermaphroditism caused by steroid 5alpha-reductase deficiency is an autosomal recessive disorder. The enzyme steroid 5alpha-reductase 2 (encoded by the SRD5A2 gene) catalyses the conversion of testosterone to dihydrotestosterone, which is required for normal differentiation of the external male genitalia. This report describes the molecular analysis of the 5alpha-reductase type 2 gene in a Brazilian patient who was raised as a female, underwent a reversal of gender role behavior, and is now a married man. This patient is a compound heterozygote bearing an A-->G mutation within exon 2, changing codon 126 from Glu to Arg on one allele and a novel single base deletion (418delT) causing a frameshift mutation at codon 140 in the same exon, on the other allele. This last mutation probably leads to the synthesis of a truncated protein, because a premature termination signal is created at codon 159.

3-Oxo-5-alpha-Steroid 4-Dehydrogenase↗
PubMed2004

Discordant phenotypes in first cousins with UBE3A frameshift mutation.

Mutations have been found in the UBE3A gene (E6-AP ubiquitin protein ligase gene) in many Angelman syndrome (AS) patients with no deletion, no uniparental disomy, and no imprinting defect. UBE3A mutations are more frequent in familial than in sporadic patients and the mutations described so far seem to cause similar phenotypes in the familial affected cases. Here we describe two first cousins who have inherited the same UBE3A frameshift mutation (duplication of GAGG in exon 10) from their asymptomatic mothers but present discordant phenotypes. The proband shows typical AS features. Her affected cousin shows a more severe phenotype, with asymmetric spasticity that led originally to a diagnosis of cerebral palsy. Proband's brain MRI shows mild cerebral atrophy while her cousin's brain MRI shows severe brain malformation. This family demonstrates that, although brain malformation is unusual in AS, presence of a brain malformation does not exclude the diagnosis of AS. Also, this UBE3A mutation was transmitted from the cousin's grandfather to only two sisters among eight full siblings, raising the hypothesis of mosaicism for this mutation.

Female↗
PubMed2000

Abnormal nephron development associated with a frameshift mutation in the transcription factor hepatocyte nuclear factor-1 beta.

BACKGROUND: The transcription factor hepatocyte nuclear factor (HNF)-1 beta functions as a homodimer or as a heterodimer with the structurally related protein HNF-1 alpha. Both are expressed sequentially in rat kidney development, with HNF-1 beta being detected from the earliest inductory phases. HNF-1 beta gene mutations are associated with a unique disorder characterized by maturity-onset diabetes of the young (MODY) and early-onset and progressive nondiabetic renal dysfunction, which may lead to chronic renal failure. METHODS: The HNF-1 beta gene was screened for mutations in six subjects with early-onset diabetes and a history of renal dysfunction in the subjects or their families. RESULTS: A novel frameshift mutation in exon 4 of the HNF-1 beta gene and a deletion of CCTCT at codons 328 to 329 were detected in one subject. She was diagnosed as diabetic at the age of 21 in her second pregnancy. Glucose tolerance rapidly deteriorated over 18 months as a result of beta-cell dysfunction. The HNF-1 beta mutation arose de novo on a paternal chromosome and cosegregated with renal abnormalities in her family. The proband had bilateral small cysts in normal-sized kidneys and a reduced creatinine clearance of 66 mL/min (NR 80-120). Her first pregnancy was terminated at 17 weeks following an ultrasound diagnosis of bilateral, nonfunctioning cystic kidneys. Her first-born child had a small multicystic, dysplastic right kidney and a dysplastic left kidney with a reduced creatinine clearance (40 mL/min per 1.73 m2). Histologic examination of the large (5.8 vs. 1.4 g), polycystic fetal kidneys showed no normal nephrogenesis. CONCLUSIONS: These studies indicate that HNF-1 beta plays a central role in normal kidney development and pancreatic beta-cell function, and suggest that one mechanism by which HNF-1 beta gene mutations may cause renal dysfunction are by their effects on nephron development.

Abortion, Induced↗
PubMed1991

Frameshift mutations in the bacteriophage Mu repressor gene can confer a trans-dominant virulent phenotype to the phage.

Virulent mutations in the bacteriophage Mu repressor gene were isolated and characterized. Recombination and DNA sequence analysis have revealed that virulence is due to unusual frameshift mutations which change several C-terminal amino acids. The vir mutations are in the same repressor region as the sts amber mutations which, by eliminating several C-terminal amino acids, suppress thermosensitivity of repressor binding to the operators by its N-terminal domain (J. L. Vogel, N. P. Higgins, L. Desmet, V. Geuskens, and A. Toussaint, unpublished data). Vir repressors bind Mu operators very poorly. Thus the Mu repressor C terminus, either by itself or in conjunction with other phage or host proteins, tunes the DNA-binding properties at the repressor N terminus.

Amino Acid Sequence↗
PubMed2006

Frameshift mutation in GJA12 leading to nystagmus, spastic ataxia and CNS dys-/demyelination.

Mutations in GJA12 have been shown to cause Pelizaeus-Merzbacher-like disease (PMLD). We present two additional patients from one family carrying a homozygous frameshift mutation in GJA12. Both presented initially with nystagmus. The older girl developed ataxia first, then progressive spastic ataxia. The younger boy suffered from severe sensory neuropathy. Magnetic resonance imaging (MRI) of both children showed progressive demyelination in addition to dysmyelination, and also characteristic brainstem abnormalities. In children with nystagmus, ataxia and dysmyelination, mutation analysis of GJA12 should be considered early, especially if inheritance is autosomal recessive.

Ataxia↗
PubMed1997

An Escherichia coli topB mutant increases deletion and frameshift mutations in the supF target gene.

We have improved a system to examine forward mutations that occurred in the supF gene of Escherichia coli placed on a multicopy plasmid. Using this system, we determined the mutational specificity for a topB deletion mutator in which topoisomerase III is hampered. The frequency of supF- mutations in topB strain was 4.9 x 10(-7), that is essentially the same as that in wild-type strain, 3.1 x 10(-7). Half the number of the supF- mutations were large deletions, where a specific deletion among a 10-base pair direct repeat dominated, but other types of deletions were also found. Most of the deletions were associated with the presence of directly repeated sequences capable of accounting for their endpoints. Frameshift mutations in topB strain also significantly increased compared with those of wild-type (17 vs. 2%). Base substitutions comprised 27% of the events, specificity of which in topB strain was the same as that in wild-type strain. The present data suggest that topB is a novel class of mutator that strongly induces repeated sequence dependent deletion mutagenesis and high frequencies of frameshift mutagenesis.

Base Sequence↗
PubMed1998

Early and severe neurological features in a Wilson disease patient compound heterozygous for two frameshift mutations.

UNLABELLED: We describe a patient with Wilson disease who presented at 11 years of age with neurological symptoms and subsequent rapid progression of neurological impairment but absent hepatic manifestations. Molecular analysis showed compound heterozygosity for two frameshift mutations, 2299insC and 214delAT, which most likely result in an absent or inactive protein product. Mutation-phenotypic analysis indicates that this genotype does not explain the severe phenotype, suggesting the presence of modifying factors. CONCLUSION: Wilson disease may present even in childhood or adolescence with neurological abnormalities in the absence of hepatic manifestations.

Child↗
PubMed1995

Frameshift mutation in codon 176 of the p53 gene in rat esophageal epithelial cells transformed by benzo[a]pyrene dihydrodiol.

Mutations in the p53 tumor suppressor gene have been associated with exposure to environmental chemical carcinogens. Cultured rat esophageal epithelial cells were transformed in vitro by treatment with benzo[a]pyrene dihydrodiol (BP-DHD). A BP-DHD-transformed cell line and control cell lines were analyzed for mutations in the p53 gene and in the Ha-ras gene by single-strand conformation polymorphism analysis of polymerase chain reaction-amplified products and direct DNA sequencing. The deletion of one cytosine in codons 174-176 (TGCCCCCAC-->TGCCCCAC) of the p53 gene was found only in the BP-DHD-transformed cell line. The BP-DHD-transformed cells were highly invasive and tumorigenic when transplanted into syngeneic rats, whereas control lines either were nontumorigenic or formed epithelial cysts. BP-DHD-transformed cells and control lines were negative for mutations in the Ha-ras gene. Our results suggest that the tumorigenic potential of the BP-DHD-transformed cell line is associated with a frameshift mutation in codon 176 of the p53 gene but not with mutations in the Ha-ras gene. The G/C-rich codons 174-176 in the rat p53 gene may be specific targets for BP-DHD.

Animals↗