None approved for ASO; Bisphosphonates used for symptom management
Osteogenesis imperfecta (OI), commonly known as brittle bone disease, is a group of genetic disorders of connective tissue characterized by bones that break easily, often from little or no apparent cause. The most common forms are caused by dominant mutations in the COL1A1 or COL1A2 genes, which encode the two chains of type I collagen — the major structural protein of bone, skin, tendons, and other connective tissues.
OI ranges from mild (Type I, with few fractures and near-normal stature) to lethal (Type II, with death in the perinatal period due to respiratory failure from rib fractures). Intermediate forms (Types III and IV) cause moderate to severe bone fragility, progressive skeletal deformity, short stature, and variable hearing loss. Other features can include blue sclerae, dentinogenesis imperfecta, and joint hypermobility.
The disease mechanism in dominant OI is typically dominant-negative: the mutant collagen chain is incorporated into the collagen triple helix but disrupts its structure, producing collagen fibers that are weaker than normal. A single mutant chain can compromise the entire triple helix (which requires two COL1A1 chains and one COL1A2 chain), meaning that the mutant protein actively interferes with the function of the normal protein produced from the other allele.
Allele-selective gene silencing with ASOs offers a promising therapeutic approach for dominant-negative OI. By designing an ASO that specifically targets the mutant COL1A1 mRNA for RNase H-mediated degradation while sparing the wild-type transcript, the cell would produce collagen exclusively from the normal allele. Although this would reduce total collagen production by half, collagen made entirely from normal chains is structurally sound — and haploinsufficiency of COL1A1 causes mild OI (Type I), which is far less severe than the dominant-negative forms.
Preclinical studies have demonstrated the feasibility of allele-selective ASO approaches for OI. ASOs designed to discriminate between mutant and wild-type COL1A1 transcripts based on the specific mutation sequence have shown selective knockdown in cell culture and animal models, with improvements in collagen quality and bone strength.
Pequliar designs allele-selective ASO candidates for osteogenesis imperfecta, targeting the patient’s specific COL1A1 or COL1A2 mutation for selective degradation of the mutant transcript. The platform optimizes ASO sequences for mismatch discrimination between the mutant and wild-type alleles, scores candidates for binding affinity and off-target safety, and provides synthesis-ready sequences with full chemistry assignment.
Describe your mutation and get ranked, synthesis-ready ASO candidates in minutes. $399 per design.
Start a designPequliar is a computational research tool for informational purposes only. All sequences are computationally predicted candidates that have not been experimentally validated. Pequliar does not prescribe, recommend, or administer any compound. Independent validation by qualified professionals is required.