Osteogenesis imperfecta

Osteogenesis imperfecta is a skeletal genetic disease caused by mostly autosomal dominant (also recessive forms) variants in COL1A1, COL1A2, acting through dominant-negative and haploinsufficiency mechanisms. Within this volume's rankable burden cohort it sits at residual rank 8 of 23, where established therapy is partially disease-modifying. That order is a provisional [H]-grade prioritisation device, not a registry-locked ranking.

Osteogenesis imperfecta is inherited as mostly autosomal dominant (also recessive forms) and acts by dominant-negative (glycine substitutions) / haploinsufficiency (null alleles) ([L]). Its pre-treatment burden proxy is 0.6400 and, after the established therapy's efficacy offset e = 0.3000 is applied, its residual burden score is 0.4480 ([H]), placing it at residual rank 8 of 23.

Gene, inheritance, and molecular mechanism

Osteogenesis imperfecta is inherited as Autosomal dominant inheritance; Autosomal recessive inheritance; X-linked recessive inheritance [L] and is classified mechanistically as dominant-negative (glycine substitutions) / haploinsufficiency (null alleles) [L]. COL1A1 and COL1A2 encode the two chains of type I collagen, the dominant protein of bone matrix. Glycine substitutions poison the collagen triple helix (a dominant-negative effect), while null alleles simply reduce collagen output (haploinsufficiency).

Inheritance source: medgen:esummary:ModeOfInheritance:2026-06-17. Mechanism source: curated_rule:collagen_dn; established molecular genetics; OMIM(row) molecular section. These are observed, cited inputs; the inheritance and mechanism classification is the reproducible analysis layer (C-D1).

In-scope clinical involvement

The phenotype is recurrent fractures with minimal trauma, together with variable dentinogenesis imperfecta, blue sclerae, and adult-onset hearing loss, ranging from a perinatal-lethal end to a mild form.

Organ systems [L] from HPO phenotype.hpoa v2026-06-06 (OMIM 120150,166200,166210,166220,259420); P-aspect terms rolled up to HP:0000118 organ-system categories via hp.obo.

Reproducible burden position

Of the five axes, 5 are scored (the rankability cut is ≥ 3 of 5); the pre-treatment composite is the renormalised mean over the scored axes, raw_burden = 0.6400. The registry-grade [L] axes here are onset, mortality, and disability (onset from the Orphanet AverageAgeOfOnset register / HPO; disability from the GBD 2013 disability-weights table). Progression and severity remain an [H] inference from the cited clinical definition.

Because those axes carry [H] inferences, this position is a provisional [H] prioritisation device, not a registry-locked ranking.

The natural-history registry passes have been run against Orphanet/Orphadata (CC BY 4.0, R6) and the openly published GBD 2013 disability-weights table (Salomon et al., CC BY, R7). R6 lifts onset to registry-grade [L] across most of the cohort (earliest AverageAgeOfOnset category, entity-anchored per ORPHAcode, Exact OMIM↔ORPHA only); R7 lifts disability to [L] where one dominant untreated sequela maps to a named GBD health state (published disability weight binned by declared cut-points), and independently corroborates a mortality axis from PMC survival literature where a quantitative disease-typical figure exists. Severity now lifts to registry [L] for the one disease whose dominant sequela carries a cited HPO Severity-modifier annotation (the HP:0012824 subtree, R8); for the rest the open HPO severity annotations are feature-level (using one feature as the disease tier would be a category error), so severity stays [H]/[O] with the obstacle named. Progression lifts to registry [L] where a cited PMC open-access source states a disease-level magnitude for the dominant untreated sequela and the frozen R3 tier function derives the tier from that verbatim sentence (R9, curated dominant-sequela join, non-spectrum); for the rest progression stays [H]/[O]. The OMIM clinical synopsis (the disease-level alternative) is API-key-gated and the key is unobtainable for an individual researcher — that path is removed, not guessed.

Osteogenesis imperfecta perturbs bone-matrix formation, part of the normal-development baseline the carried morphogenesis engine simulates.

Established treatment and residual burden

The established disease-directed approach is bisphosphonate therapy with orthopedic and rehabilitative management. Mechanistically: bisphosphonate anti-resorptive action increases bone mineral density [L].

Its effect on natural history is classified disease-modifying (partial), mapping to an efficacy offset e = 0.3000 and a residual factor R_treat = 0.7000. Applied to the pre-treatment proxy this gives the residual burden score 0.4480, moving the disease from raw rank 17 to residual rank 8 (shift 9).

Evidence tier: accession-dated to the GeneReviews NBK1295 Management section [L] (initial posting January 28, 2005; last revision May 29, 2025; retrieved 2026-06-18; corroborating term(s): “bisphosphonate, orthopedic, rehabilitative”). The natural-history axis grades remain a mix of [L] (GeneReviews-corroborated) and [H] (definition-only), so the burden order is still provisional.