Dataset Information

BRCA2 T2722R is a deleterious allele that causes exon skipping.

ABSTRACT: Patients with a strong family history of breast cancer are often counseled to receive genetic screening for BRCA1 and BRCA2 mutations, the strongest known predictors of breast cancer. A major limitation of genetic testing is the number of inconclusive results due to unclassified BRCA1 and BRCA2 sequence variants. Many known deleterious BRCA1 and BRCA2 mutations affect splicing, and these typically lie near intron/exon boundaries. However, there are also potential internal exonic mutations that disrupt functional exonic splicing enhancer (ESE) sequences, resulting in exon skipping. Using previously established sequence matrices for the scoring of putative ESE motifs, we have systematically examined several BRCA2 mutations for potential ESE disruption mutations. These predictions revealed that BRCA2 T2722R (8393C-->G), which segregates with affected individuals in a family with breast cancer, disrupts three potential ESE sites. Reverse-transcriptase polymerase chain reaction analysis confirms that this mutation causes exon skipping, leading to an out-of-frame fusion of BRCA2 exons 17 and 19. This represents the first BRCA2 missense mutation shown to be a predicted deleterious protein-truncating mutation and suggests a potentially useful method for determining the clinical significance of a subset of the many unclassified variants in BRCA1 and BRCA2.

SUBMITTER: Fackenthal JD

PROVIDER: S-EPMC379197 | biostudies-literature | 2002 Sep

REPOSITORIES: biostudies-literature

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BRCA2 T2722R is a deleterious allele that causes exon skipping.

Fackenthal James D JD Cartegni Luca L Krainer Adrian R AR Olopade Olufunmilayo I OI

American journal of human genetics 20020719 3

Patients with a strong family history of breast cancer are often counseled to receive genetic screening for BRCA1 and BRCA2 mutations, the strongest known predictors of breast cancer. A major limitation of genetic testing is the number of inconclusive results due to unclassified BRCA1 and BRCA2 sequence variants. Many known deleterious BRCA1 and BRCA2 mutations affect splicing, and these typically lie near intron/exon boundaries. However, there are also potential internal exonic mutations that d ...[more]

PMID: 12145750

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Project description:Schizophrenia is a heterogeneous psychiatric disorder characterized by positive symptoms such as hallucinations and delusions, negative symptoms such as anhedonia and flat affect, and cognitive impairment. Recently, glucuronate (GlucA) levels were reported to be significantly higher in serum of patients with schizophrenia than those in healthy controls. The accumulation of GlucA is known to be related to treatment-resistant schizophrenia, since GlucA is known to promote drug excretion by forming conjugates with drugs. However, the cause of GlucA accumulation remains unclear. Aldo-keto reductase family one member A1 (AKR1A1) is an oxidoreductase that catalyzes the reduction of GlucA. Genetic loss of AKR1A1 function is known to result in the accumulation of GlucA in rodents. Here, we aimed to explore genetic defects in AKR1A1 in patients with schizophrenia, which may result in the accumulation of GlucA. We identified 28 variants of AKR1A1 in patients with schizophrenia and control subjects. In particular, we identified a silent c.753G > A (rs745484618, p. Arg251Arg) variant located at the first position of exon 8 to be associated with schizophrenia. Using a minigene assay, we found that the c.753G > A variant induced exon 8 skipping in AKR1A1, resulting in a frameshift mutation, which in turn led to truncation of the AKR1A1 protein. Using the recombinant protein, we demonstrated that the truncated AKR1A1 completely lost its activity. Furthermore, we showed that AKR1A1 mRNA expression in the whole blood cells of individuals with the c.753G > A variant tended to be lower than that in those without the variants, leading to lower AKR activity. Our findings suggest that AKR1A1 carrying the c.753G > A variant induces exon skipping, leading to a loss of gene expression and enzymatic activity. Thus, GlucA patients with schizophrenia with the c.753G > A variant may show higher GlucA levels, leading to drug-resistant schizophrenia, since drug excretion by GlucA is enhanced.

Dataset Information

BRCA2 T2722R is a deleterious allele that causes exon skipping.

Publications

BRCA2 T2722R is a deleterious allele that causes exon skipping.

Similar Datasets

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