Accelerate Therapeutic Development of Genetic Diseases From SNP Functional Analysis to Drug Candidate

Functional validation of genetic variants associated with rare diseases 

An estimated ~30M or 1 in 10 Americans suffer from a rare disease (classified as such impacting fewer two hundred thousand individuals¹). Of 7000 catalogued rare diseases, up to 80% appear likely to be genetic in origin. FDA-approved therapies currently address fewer than 5% of these. The evolution of whole exome sequencing (WES) and other genotyping methods have expanded understanding of rare diseases in terms of sequence variation at the genome level^{2, 3, 4} However, for most genetic variants, insight into their functional role in the etiology of disease is lacking. This impedes the development of informative diagnostics and therapeutics. Validation of monogenic rare disease targets⁶ therefore requires 1) identification of sequence variants associated with disease and 2) the development of evidence that a specific genetic variant or SNP has a function in its pathophysiology. To meet this challenge, the cell-based platform created by Multispan enables the analysis of the impact of genetic variation on biological pathway activity in rare diseases. 

Tools for therapeutics development targeting rare diseases 

A major goal of rare disease research is to inform therapeutic intervention to cure or alleviate the effects of disease. Figure 1 outlines how Multispans’s approach feeds the development of high throughput screening (HTS) assays, animal models and other tools to support efforts to develop new therapeutics. In addition to classical therapeutic modalities (small molecules, antibodies) tools such as siRNA, CRISPR and Protac are beginning to be used to target rare diseases, either to downregulate activity or expression of a target, or in the case of CRISPR, to introduce a “corrected” copy of a mutated gene Collectively, these tools have the potential to extend the range of targets that may be considered as druggable. Since mutations that give rise to rare diseases may have either a gain (GOF)-or loss-of-function (LOF) effect on the target^5,6, our expertise with this spectrum of therapeutic approaches paired with screening tools and animal models provides a flexible platform for targeting a specific disease. Indeed, Multispan has decades of accumulated expertise with targets impacted by both GOF and LOF mutations. For example, mutations in the GPCR rhodopsin can lead to the development of autosomal dominant retinitis pigmentosa⁷. A spectrum of GOF and LOF mutations also play a role in more than sixty other rare diseases currently associated with GPCRs^{7, 8}. 

The Multispan platform 

Multispan’s platform takes the experimental approaches⁹ with our deep expertise in cell biology and assay development to address the following key questions about a potential target (Figure 2) 

1. What is known about the biological function of the target including its role in biological pathways and potential downstream effectors?
2. What is known about the association between the target and pathophysiology of disease given that this may be indirect? 
3. Does genetic variation affect the primary structure, expression levels, cellular location, tissue expression of the target in disease-affected tissues?
   
4. How does the biological activity of the normal and rare disease target compare in cellular assays?

We use targeted functional rescue to compare the cellular biology of variant and normal forms of the gene together with pathway dissection tools such as ASO, mRNA, CRISPR and Protac^9,10. We combine data from these analyses, multi-omics assays and publicly available clinical, genetic and functional data analysis to provide a deep understanding of the effects of genetic variants on biological activity. These findings can identify potential biomarkers for further analysis, inform development of diagnostics as well as biochemical and/or cellular assays as well as tissue and animal models to inform downstream preclinical studies.