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PubMed2001

Multifunctional regulatory proteins that control gene expression in both the nucleus and the cytoplasm.

The multistep pathway of eukaryotic gene expression involves a series of highly regulated events in the nucleus and cytoplasm. In the nucleus, genes are transcribed into pre-messenger RNAs which undergo a series of nuclear processing steps. Mature mRNAs are then transported to the cytoplasm, where they are translated into protein and degraded at a rate dictated by transcript- and cell-type-specific cues. Until recently, these individual nuclear and cytoplasmic events were thought to be primarily regulated by different RNA- and DNA-binding proteins that are localized either only in the nucleus or only the cytoplasm. Here, we describe multifunctional proteins that control both nuclear and cytoplasmic steps of gene expression. One such class of multifunctional proteins (e.g., Bicoid and Y-box proteins) regulates both transcription and translation whereas another class (e.g., Sex-lethal) regulates both nuclear RNA processing and translation. Other events controlled by multifunctional proteins include assembly of spliceosome components, spliceosome recycling, RNA editing, cytoplasmic mRNA localization, and cytoplasmic RNA stability. The existence of multifunctional proteins may explain the paradoxical involvement of the nucleus in an RNA surveillance pathway (nonsense-mediated decay) that detects cytoplasmic signals (premature termination codons). We speculate that shuttling multifunctional proteins serve to efficiently link RNA metabolism in the cytoplasmic and nuclear compartments.

Animals↗

PubMed2003

Missplicing resulting from a short deletion in the reelin gene causes reeler-like neuronal disorders in the mutant shaking rat Kawasaki.

The shaking rat Kawasaki (SRK) is an autosomal recessive mutant that exhibits reeler-like abnormal locomotor behaviors. The murine reeler mutants arise from several mutations in the specific gene called reelin, which result in defects of Reelin expression or secretion in the cerebral cortex and other regions of CNS. To address the issue of whether the SRK mutation also arises from a mutation in reelin, we analyzed the reelin gene in SRK. Northern analysis of reelin mRNA from normal rats showed that rat reelin was expressed as a approximately 12-kb transcript in both the cerebrum and the cerebellum, whereas reelin expression was markedly reduced in the SRK brains. In situ hybridization analysis showed that reelin mRNA in the SRK brains was expressed in Cajal-Retzius cells in the marginal zone of the cerebral cortex and outer granular cells in the cerebellar cortex in similar manners to normal controls, but its expression was considerably reduced. On Western blotting and immunohistochemical analyses using antibodies specific for the Reelin protein, no immunoproduct was recognized in the cerebral and cerebellar cortices. From the cDNA sequences, we found a 64-base heterologous sequence in SRK reelin, which contains a termination codon in the reading frame. Furthermore, genomic DNA analysis revealed that a 10-base deletion, which contains a predicted splice donor site, occurred in the SRK genomic reelin gene, resulting in "read through" into the following intron in SRK. Thus, the SRK mutation is another type of mutation that lacks expression of the functional Reelin protein and, therefore, causes the reeler phenotype.

Animals↗

PubMed2001

Targeted disruption of Col11a2 produces a mild cartilage phenotype in transgenic mice: comparison with the human disorder otospondylomegaepiphyseal dysplasia (OSMED).

Transgenic mice were prepared by homologous recombination with a Col11a2 targeting gene in which an inverted neomycin-resistant gene was inserted between restriction sites in exons 27 and 28. The targeted allele was transcribed in shortened mRNAs, which could be detected by Northern blotting. However, translation of the full-length Col11a2 chain was unable to occur because of the presence of premature termination codons within the inverted neomycin-resistant gene. Analysis of pepsin-resistant collagen chains from rib cartilage of homozygous mice demonstrated the lack of synthesis of intact alpha2(XI) chains. However, pepsin-resistant collagen chains of either alpha1(XI) or alpha1(V) were still detected on sodium dodecyl sulfate polyacrylamide gel electrophoresis. Therefore, alpha2(XI) chains are not essential for the assembly of some molecular forms of triple-helical type V/XI collagen. The phenotype was milder than in the cho/cho mouse in which, as the result of mutation, translation of the full-length alpha1(XI) chain fails to occur and the mice die at birth (Li et al., 1995). Homozygous mice without expression of an alpha2(XI) chain had a smaller body size, receding snouts, and deafness. Nasal bones in the homozygous transgenic mice were specifically shorter and dimpled on their external surfaces. Chondrocytes in growth plates of all long bones were markedly disorganized and failed to align in columns. Analysis of growth plates from transgenic mice by in situ hybridization showed expression of alpha1(II) and alpha1(XI) but not of alpha1(I) or alpha1(V) which, in contrast, were expressed in the developing bone and in the bone collar. Expression of alpha1(X) specifically in the hypertrophic cartilage was observed in normal and transgenic mice. No obvious osteoarthritis was observed throughout the life of homozygous mice up to 1 year of age, although minor morphologic anomalies in the articular cartilages were discernible. The mild phenotype is consistent with similar mutations in the COL11A2 gene seen in patients with nonocular Stickler syndrome and some patients with otospondylomegaepiphyseal dysplasia (OSMED), as well as in patients with a nonsyndromic form of deafness called DFNA13.

Animals↗

PubMed1990

Nonsense suppression in Dictyostelium discoideum.

We describe the generation of Dictyostelium discoideum cell lines that carry different suppressor tRNA genes. These genes were constructed by primer-directed mutagenesis changing a tRNA(Trp)(CCA) gene from D. discoideum to a tRNA(Trp)(amber) gene and changing a tRNA(Glu)(UUC) gene from D. discoideum to a tRNA(Glu)(ochre) as well as a tRNA(Glu)(amber) gene. These genes were stably integrated into the D. discoideum genome together with a reporter gene. An actin 6::lacZ gene fusion carrying corresponding translational stop signals served as a reported. Active beta-galactosidase is expressed only in D. discoideum strains that contain, in addition to the reporter, a functional suppressor tRNA. Both amber suppressors are active in D. discoideum without interfering significantly with cell growth and development. We failed, however, to establish cell lines containing a functional tRNA(Glu)(ochre) suppressor. This may be due to the fact that nearly every message from D. discoideum known so far terminates with UAA. Therefore a tRNA capable of reading this termination codon may not be compatible with cell growth.

Base Sequence↗

PubMed1993

Characterization of two new CD18 alleles causing severe leukocyte adhesion deficiency.

Leukocyte adhesion deficiency (LAD) is an autosomal recessive disease caused by heterogeneous mutations within the gene encoding the common beta subunit (CD18) of the three leukocyte integrins LFA-1 (CD11a/CD18), Mac-1 (CD11b/CD18), and p150,95 (CD11c/CD18). Based on the level of expression of CD18 on patient leukocytes, two phenotypes of LAD have been defined (severe and moderate) which correlate with the severity of the disease. We have investigated the molecular basis of the disease in two unrelated severe patients (HS and ZJO). Both patients share a complete absence of CD18 protein precursor and cell surface expression, but they differ in the level of CD18 mRNA, which is normal in HS and undetectable by Northern blot in ZJO. Determination of the primary structure of the patient HS CD18 mRNA revealed a 10-base pair deletion between nucleotides 190-200 (CD18 exon 3), which eliminates residues 41-43 and causes a frameshift into a premature termination codon 17 base pairs downstream from the deleted region. The 10-base pair frameshift deletion maps to a region of the CD18 gene where aberrant mRNA processing has been detected in HS and two other unrelated LAD patients. In the ZJO patient, amplification of lymphoblast CD18 mRNA demonstrated the presence of a non-sense mutation in the third nucleotide of the triplet encoding Cys534 (TGC-->TGA), within exon 12. Both genetic abnormalities were also detected at the genomic level, and affect the restriction pattern of their corresponding genes, thus enabling the detection of the mutant alleles among healthy heterozygous alleles in family studies. The identification of two new LAD CD18 alleles, either carrying a non-sense mutation (ZJO) or a partial gene deletion (HS), further illustrates the heterogeneity of the genetic alterations in LAD.

Alleles↗

PubMed2003

Serrated adenomas and mixed polyposis caused by a splice acceptor deletion in the mouse Smad4 gene.

Serrated adenomas, hyperplastic polyps, and admixed hyperplastic/adenomatous polyps form a distinct group of colorectal tumors, the molecular genetic basis of which is still poorly understood. We describe a novel mouse model for serrated adenomas and mixed polyposis, here referred to as Sad (serrated adenomas), caused by a spontaneously risen splice site mutation in the murine Smad4 gene. The Sad chromosomal region was identified by genetic linkage and loss of heterozygosity (LOH) analysis. Subsequently, several candidate genes were investigated by expression and mutation analysis. By use of genetic linkage and LOH analysis, we mapped the Sad candidate to mouse chromosome 18, 44-48 cM, syntenic to human chromosome band 18q21. Within this chromosomal interval, the Smad2, Smad4, and Smad7 genes were analyzed for the presence of a disease-causing mutation in affected animals. A single nucleotide (nt) deletion was identified in the intron 5/exon 6 splice acceptor site of the Smad4 gene. The single base deletion results in a frameshift and an early termination codon through activation of a cryptic splice site 4 nt downstream in exon 6. The resulting mRNA is unstable, and the Sad mutation is thus likely to represent a null allele. Identification of a Smad4 mutation in the Sad mouse model provides further support for the involvement of the Smad genes, and thus the TGFB pathway, in the serrated/hyperplastic route to colorectal cancer.

Adenomatous Polyps↗

PubMed2003

Differentiating pathogenic mutations from polymorphic alterations in the splice sites of BRCA1 and BRCA2.

About 4% of all BRCA1 and BRCA2 alterations reported to the Breast Information Core database are splice site variants. Only a limited number of them have been studied at the RNA level. By BRCA1 and BRCA2 mutation analysis of breast/ovarian cancer families, we identified two novel and eight previously reported potential splice site mutations, never characterized at the cDNA level before. RT-PCR was performed to determine whether these variants disrupted correct splicing. To ensure efficient detection of transcripts containing premature termination codons, a nonsense-mediated mRNA decay inhibitor was added to the lymphoblastoid cell lines of the patients before RNA extraction. We found that BRCA1 IVS3+3A>C, 4304G>A (in the last codon of exon 12), and IVS19+2delT and BRCA2 IVS6+1G>A, IVS23-2A>G, and IVS24+1G>A lead to aberrant transcripts in lymphocytes. Therefore, they were considered to be true pathogenic mutations, predisposing carriers to cancers of the hereditary breast/ovarian cancer syndrome. BRCA2 IVS24-16T>C is a frequent polymorphism in linkage disequilibrium, with a polymorphic stop codon in exon 27, K3326X. BRCA1 IVS2-14C>T and BRCA2 IVS9-5insT and IVS25+9A>C represent rare variants, not disrupting normal splicing in blood lymphocytes. However, some of the alterations may act differently, qualitatively and/or quantitatively, in breast or ovarian tissues. The data provided in this paper allowed more accurate risk estimation of patients and relatives carrying the mutations described herein and have facilitated genetic counseling. Furthermore, our study is important for a better understanding of splicing mechanisms and revealed new patterns of alternative splicing in BRCA1 and BRCA2.

Adult↗

PubMed2002

Intron retention and frameshift mutations result in severe pyruvate carboxylase deficiency in two male siblings.

This paper describes the molecular characterization of two male siblings displaying the complex (Type B) form of pyruvate carboxylase (PC) deficiency in which severe neonatal lactic acidosis and redox abnormalities results in death within the first few weeks of life. The two male siblings were found to be compound heterozygous for a TAGG deletion at the exon15/intron15 splice site (IVS15+2-5delTAGG) and a dinucleotide deletion in exon 16 (2491-2492delGT) of the PC gene. We also demonstrate through RT-PCR and sequencing of aberrant transcripts that the IVS15+2-5delTAGG results in the retention of intron 15 during pre-mRNA splicing. In addition, both deletions are predicted to result in a frameshift to generate a premature termination codon such that the encoded mRNA could be subject to nonsense mediated decay.

Alternative Splicing↗

PubMed2003

Pseudoexon activation in the DMD gene as a novel mechanism for Becker muscular dystrophy.

We report the characterization of two deep intronic mutations in the Duchenne muscular dystrophy (DMD) gene of two unrelated Becker muscular dystrophy (BMD) patients, causing the aberrant inclusion of a pseudoexon in the mature transcripts. These two mutations were identified by the use of RT-PCR on transcripts isolated from muscle. The first abnormally large transcript resulting from a 58-bp insertion between exon 62 and exon 63 was identified in a BMD patient with mental retardation. The origin of this transcript was a mutation in intron 62 (IVS62-285A>G), which resulted in the occurrence of a high quality donor splice site. The IVS25+2036A>G in intron 25 was identified in a subclinical BMD patient with high CK levels. The mutation reinforces the strength of a pre-existing acceptor splice site, resulting in activation of an intronic pseudoexon of 95 bp. By using DHPLC, the patient's mother was found to be a somatic mosaic. The insertion of these newly recognized extra exons leads to premature termination codons, but we could observe that some degree of normal splicing was taking place in both patients. The detection of these residual full length transcripts is consistent with the clinical presentation and dystrophin analyses. This is the first report of pseudoexon activation as a mechanism for Becker muscular dystrophy, and this reveals further the diversity of genetic abnormalities causing BMD.

Adult↗

PubMed2004

Nonclassical splicing mutations in the coding and noncoding regions of the ATM Gene: maximum entropy estimates of splice junction strengths.

Ataxia-telangiectasia (A-T) is an autosomal recessive neurological disorder caused by mutations in the ATM gene. Classical splicing mutations (type I) delete entire exons during pre-mRNA splicing. In this report, we describe nine examples of nonclassical splicing mutations in 12 A-T patients and compare cDNA changes to estimates of splice junction strengths based on maximum entropy modeling. These mutations fall into three categories: pseudoexon insertions (type II), single nucleotide changes within the exon (type III), and intronic changes that disrupt the conserved 3' splice sequence and lead to partial exon deletion (type IV). Four patients with a previously reported type II (pseudoexon) mutation all shared a common founder haplotype. Three patients with apparent missense or silent mutations actually had type III aberrant splicing and partial deletion of an exon. Five patients had type IV mutations that could have been misinterpreted as classical splicing mutations. Instead, their mutations disrupt a splice site and use another AG splice site located nearby within the exon; they lead to partial deletions at the beginning of exons. These nonclassical splicing mutations create frameshifts that result in premature termination codons. Without screening cDNA or using accurate models of splice site strength, the consequences of these genomic mutations cannot be reliably predicted. This may lead to further misinterpretation of genotype-phenotype correlations and may subsequently impact upon gene-based therapeutic approaches.

Ataxia Telangiectasia↗

PubMed1992

Novel Tay-Sachs disease mutations from China.

We describe three HEXA mutations associated with infantile Tay-Sachs disease (TSD) in three unrelated nonconsanguineous Chinese families. Novel mutations were found in two of these families. The third is a previously reported mutation (G-->A transition at nt 1444) (Nakano et al., 1988). Direct sequencing of PCR products identified a novel insertion of an A after nt 547 in family 1. This change generates an early termination codon 6 bp downstream from the insertion site. Allele-specific oligonucleotide hybridization confirmed homozygosity in the proband. Single strand conformational polymorphism analysis and direct sequencing of amplified exon 13 revealed a T-->C transition at nt 1453 with the corresponding amino acid substitution W485R in the second family. This mutation creates an Fnu4HI restriction site. The proband is homozygous for this allele. When the site-specific mutagenized alpha cDNA carrying the T-->C transition at nt 1453 was expressed in COS 1 cells hexosaminidase S activity was not detectable above background. A G-->A transition at nt 1444 (exon 13) corresponding to the E482K substitution was found in the third family. This mutation occurs at a CpG dinucleotide. It has been reported in an Italian TSD proband and causes defective intracellular transport of the alpha-subunit from the rough endoplasmic reticulum to the Golgi apparatus.

Animals↗

PubMed1992

An unusual genotype in an Ashkenazi Jewish patient with Tay-Sachs disease.

The Ashkenazi Jewish population is enriched for carriers of a fatal form of Tay-Sachs disease, a recessive inherited disorder caused by mutations in the alpha-chain of the lysosomal enzyme beta-hexosaminidase A. Approximately 20% of the Ashkenazi carriers harbor a splice junction defect while about 78% bear a 4 base pair (bp) insertion. However, the Ashkenazi Jewish patient used in the original description of the 4 bp insertion carried this lesion in only 1 allele and was negative for the splice junction mutation. We cloned the insertion negative allele and by sequence analysis of the exons found a point mutation in exon 11 that results in substitution of Trp392 with a premature termination codon. Nine Ashkenazi Jewish carriers that tested negative for the major and minor mutations as well as for a lesion causing an adult form of Tay-Sachs disease did not carry the base change defect, suggesting that it may be a recent and/or rare mutation. This finding also indicates that screening the Ashkenazi population solely by recombinant DNA methods for the splice junction, 4 bp insertion, and adult mutations may result in occasional false negatives.

Alleles↗

PubMed1994

Mutations in PAX3 associated with Waardenburg syndrome type I.

Waardenburg syndrome (WS) types I, II, and III (McKusick #14882, #19351, and #19350) are related autosomal dominant disorders characterized by sensorineural hearing loss, dystopia canthorum, pigmentary disturbances, and other developmental defects. Disease causing PAX3 mutations have been identified in a few families from each of the three disease subtypes, WS-I, WS-II, and WS-III. In others, although the mutations have not been pinpointed, linkage with the PAX3 locus on chromosome 2q35 has been demonstrated. The PAX3 protein is a transcription factor that contains both a paired-domain and a homeodomain DNA binding motif and appears to play a key role during embryogenesis. In this report, we describe two mutations in the human PAX3 gene that cause WS type I. One mutation is a deletion/frameshift in the paired-domain of PAX3 and results in a protein without functional DNA binding domains. The second mutation is a single-base substitution and results in a premature termination codon in the homeodomain of PAX3. This is the first demonstration of a mutation in the homeodomain DNA binding motif in this protein resulting in WS and one of the few examples of a mutation in a homeodomain of any protein that results in human disease.

Amino Acid Sequence↗

PubMed1995

Identification of a novel mutation causing aspartylglucosaminuria reveals a mutation hotspot region in the aspartylglucosaminidase gene.

Aspartylglucosaminuria (AGU) is a recessively inherited metabolic disorder caused by the deficiency of a lysosomal enzyme, aspartylglucosaminidase. The worldwide most common mutation causing the disease is the AGUFin, enriched in Finland; all the other known AGU mutations are family-specific. We developed exon-specific primers to facilitate mutation search directly from the genomic DNA and identified a novel mutation, designated AGUFin minor, in seven Finnish AGUFin compound heterozygote patients. This deletion/frameshift mutation creates a premature translational termination codon and was shown to result in severely reduced transcript levels as quantified by the solid-phase minisequenching method. Genealogical data on this novel mutation suggest its relatively recent introduction into the population. The AGU mutations identified so far have been reported to be evenly distributed throughout the 1 kb coding region of the AGA cDNA. We identified a mutation hotspot region of 40 bp within the 12.5 kb AGA gene containing two previously identified mutations and the novel AGUFin minor mutation characterized in this study.

Acetylglucosamine↗

PubMed1995

Identification of five novel inactivating mutations in the human thyroid peroxidase gene by denaturing gradient gel electrophoresis.

Thyroid peroxidase (TPO) is the key enzyme in the synthesis of thyroid hormones. Defects in the TPO gene are reported to be the cause of congenital hypothyroidism due to a Total Iodide Organification Defect (TIOD). This type of defect, where iodide taken up by the thyroid gland cannot be oxidized and bound to protein, is the most common hereditary inborn error causing congenital hypothyroidism in the Netherlands. Denaturing Gradient Gel Electrophoresis (DGGE) of PCR amplified genomic DNA was used to screen for mutations in the TPO gene of TIOD patients from nine apparently unrelated families, and seven different mutations were detected. Three frameshift mutations were found: a 20 bp duplication in exon 2, a 4 bp duplication in exon 8, and an insertion of a single nucleotide (C) at pos. 2505 in exon 14. In addition, four single nucleotide substitutions were identified: one single-base mutation resulted in a premature termination codon (C-->T at pos. 1708 in exon 10), two single-base substitutions changed an amino acid in highly conserved regions of the gene (Tyr-->Asp in exon 9 and Glu-->Lys in exon 14). The fourth single-base mutation located at the exon 10/intron 10 border altered a conserved Gly into Ser and could also affect splicing. Nine TIOD patients from five families were compound heterozygotes and six patients from four families were homozygous for one of the mentioned mutations in the TPO gene.

Base Sequence↗

PubMed1995

Homozygosity for a null allele of the insulin receptor gene in a patient with leprechaunism.

Mutations in the insulin receptor gene can cause genetic syndromes associated with extreme insulin resistance. We have investigated a patient with leprechaunism (leprechaun/Qatar-1) born of a consanguineous marriage. Postnatally, the proband had episodes of severe hypoglycemia and hyperinsulinernia, with blood glucose levels ranging from 0.9 to 9.9 mmol/L. The C peptide concentration with 1880 nmol/L, and the total insulin concentration was 1409 mU/L. The patient died outside the hospital at the age of four months. All 22 exons of the patient's insulin receptor gene were screened for mutations using denaturing gradient gel electrophoresis. Thereafter, the nucleotide sequences of selected exons were determined directly. The patient was homozygous for a mutation in exon 13; thirteen base pairs were deleted and replaced by a 5 b.p. sequence. This mutation shifts the reading frame and introduces a premature chain termination codon downstream in exon 13. Thus, the mutant allele is predicted to be a null allele that encodes a truncated receptor lacking both transmembrane and tyrosine kinase domains.

Alleles↗

PubMed2005

Identification of 29 novel and nine recurrent fibrillin-1 (FBN1) mutations and genotype-phenotype correlations in 76 patients with Marfan syndrome.

Marfan syndrome (MFS) is an autosomal-dominant disorder of the fibrous connective tissue that is typically caused by mutations in the gene coding for fibrillin-1 (FBN1), a major component of extracellular microfibrils. The clinical spectrum of MFS is highly variable and includes involvement of the cardiovascular, skeletal, ocular, and other organ systems; however, the genotype-phenotype correlations have not been well developed. Various screening methods have led to the identification of about 600 different mutations (FBN1-UMD database; www.umd.be). In this study we performed SSCP and/or direct sequencing to analyze all 65 exons of the FBN1 gene in 116 patients presenting with classic MFS or related phenotypes. Twenty-nine novel and nine recurrent mutations were identified in 38 of the analyzed patients. The mutations comprised 18 missense (47%), eight nonsense (21%), and five splice site (13%) mutations. Seven further mutations (18%) resulted from deletion, insertion, or duplication events, six of which led to a frameshift and subsequent premature termination. Additionally, we describe new polymorphisms and sequence variants. On the basis of the data presented here and in a previous study, we were able to establish highly significant correlations between the FBN1 mutation type and the MFS phenotype in a group of 76 mutation-positive patients for whom comprehensive clinical data were available. Most strikingly, there was a significantly lower incidence of ectopia lentis in patients who carried a mutation that led to a premature termination codon (PTC) or a missense mutation without cysteine involvement in FBN1, as compared to patients whose mutations involved a cysteine substitution or splice site alteration.

Amino Acid Sequence↗

PubMed2006

Intronic alterations in BRCA1 and BRCA2: effect on mRNA splicing fidelity and expression.

Germline mutations in the human breast cancer susceptibility genes BRCA1 and BRCA2 account for the majority of hereditary breast and ovarian cancer. In spite of the large number of sequence variants identified in BRCA1 and BRCA2 mutation analyses, many of these genetic alterations are still classified as variants of unknown significance (VUS). In this study, we evaluated 12 BRCA1/2 intronic variants in order to differentiate their pathogenic or polymorphic effects on the mRNA splicing process. We detected the existence of aberrant splicing in three BRCA1 variants (c.301-2delA/IVS6-2delA, c.441+1G>A/IVS7+1G>A, and c.4986+6T>G/IVS16+6T>G) and two BRCA2 variants (c.8487+1G>A/IVS19+1G>A and c.8632-2A>G/IVS20-2A>G). All but one of the aberrant transcripts arise from mutations affecting the conserved splice acceptor or donor sequences and all would be predicted to result in expression of truncated BRCA1 or BRCA2 proteins. However, we demonstrated that four of these splice-site mutations (i.e., c.301-2delA, c.441+1G>A, c.4986+6T>G, and c.8632-2A>G) with premature termination codons were highly unstable and were unlikely to encode for abundant expression of a mutant protein. Three variants of BRCA1 (c.212+3A>G/IVS5+3A>G, c.593+8A>G/IVS9+8A>G, and c.4986-20A>G/IVS16-20A>G) and four variants of BRCA2 (c.516-19C>T/IVS6-19C>T, c.7976-4_7976_3delTT/IVS17-4delTT, c.8487+19A>G/IVS19+19A>G, and c.9256- 18C>A/IVS24- 18C>A) in our studies show no effects on the normal splicing process, and they are considered to be benign polymorphic alterations. Our studies help to clarify the aberrant splicing in BRCA1 and BRCA2 as well as provide information that can be used clinically to help counsel breast/ovarian cancer prone families.

Antimetabolites, Antineoplastic↗