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The Lambda Select cII Mutation Detection System
Published on: April 26, 2018
Mutations in the TSC2 gene: analysis of the complete coding sequence using the protein truncation test (PTT)
1Department of Pathology, University of Cambridge, UK.
Human Molecular Genetics
|September 1, 1997
Summary
The protein truncation test (PTT) identified TSC2 gene mutations in 28% of families with tuberous sclerosis (TSC). This method offers a 60% detection rate for TSC2 mutations, proving effective for TSC genetic screening.
Area of Science:
- Genetics
- Molecular Biology
- Medical Research
Background:
- Tuberous sclerosis (TSC) is a genetic disorder caused by mutations in the TSC1 or TSC2 genes.
- TSC2 gene mutations account for approximately 50% of familial TSC cases.
- Previous studies identified large germline deletions (<5%) and small intragenic mutations in TSC2.
Purpose of the Study:
- To analyze mRNA from 18 unrelated TSC cases for TSC2 gene mutations using the protein truncation test (PTT).
- To evaluate the effectiveness of PTT as a screening method for TSC2 mutations.
Main Methods:
- mRNA from lymphoblastoid cell lines of 18 TSC patients was analyzed.
- Three overlapping PCR products covering the entire TSC2 coding sequence were generated.
- PCR products were translated and analyzed by SDS-PAGE to detect protein truncation shifts (PTT).
Main Results:
- Six PTT shifts were identified, with five indicating mutations predicted to produce truncated proteins.
- Specific mutations included deletions in exons 11, 12, 36, 37, and a transversion in exon 23.
- Confirmed mutations were found in 28% of families studied; an estimated 60% detection rate was achieved.
Conclusions:
- The protein truncation test (PTT) is an effective method for detecting TSC2 mutations.
- PTT offers a higher detection rate and requires less effort compared to other screening methods like SSCP.
- Alternative splicing of TSC2 exon 10 may represent a normal variant.
