SAMD12 Intronic Repeat Expansion Detection for BAFME Diagnosis
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Solution Overview
Problem
Despite comprehensive mutational analyses, the causative mutations for benign adult familial myoclonic epilepsy (BAFME) linked to specific genetic regions have not been identified, particularly within the 8q24 locus.
Innovation Solution
The identification of noncoding TTTCA and TTTTA pentanucleotide repeat expansions in the SAMD12 gene, as well as similar expansions in TNRC6A and RAPGEF2, are found to be causative mutations for BAFME, suggesting these expansions play a crucial role in hyperexcitability through RNA-mediated toxicity mechanisms.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If comprehensive mutational analyses of all exons of 38 genes are performed, then the coverage of genetic analysis is improved, but the causative mutations remain unidentified
Solution Approach 1:
The patent divides the genetic analysis into two segments: (1) analysis of coding regions (exons) of 38 genes, and (2) analysis of noncoding regions including intronic repeat expansions. This segmentation allows comprehensive coverage while identifying the specific causative mechanism - intronic TTTCA/TTTTA repeat expansions - that was missed by conventional exon-only analysis.
Solution Approach 2:
The patent transitions from analyzing only the traditional one-dimensional coding sequences to incorporating another dimension - noncoding intronic regions with repeat expansions. This dimensional expansion of genetic analysis space reveals the causative mutations located in introns of SAMD12, TNRC6A, and RAPGEF2 genes.
2Measurement precision
If repeat expansion detection is performed in multiple genes (SAMD12, TNRC6A, RAPGEF2), then the diagnostic accuracy for BAFME is improved, but the complexity of the testing procedure increases
Solution Approach 1:
The patent identifies a universal diagnostic marker - intronic TTTCA/TTTTA repeat expansions - that functions across multiple genes (SAMD12, TNRC6A, RAPGEF2) associated with BAFME. This universal mechanism allows a single detection approach to serve multiple diagnostic purposes, improving accuracy while managing complexity through standardized methodology.
Solution Approach 2:
The patent uses repeat expansion detection as an intermediary marker that mediates the diagnosis of BAFME across different genetic loci. Rather than requiring separate analyses for each gene, the repeat expansion serves as a common intermediary target that simplifies the diagnostic workflow while maintaining high accuracy.
3Measurement precision
If the repeat expansion size is used to calculate anticipated age at onset, then the predictive capability is improved, but the uncertainty in prediction increases
Solution Approach 1:
The patent utilizes the repeat expansion size as a variable parameter that correlates with age at onset. By measuring the number of repeat units in the intronic regions, the method provides a quantitative parameter change that predicts disease timing, enabling personalized prognosis while acknowledging the statistical nature of the correlation.
Data Source
AI summary
A method for determining a hyperexcitability in a subject comprising detecting a repeat expansion of TTTCA, TTTTA, or a complementary sequence thereof in a nucleic acid sample from the subject.