Table 1 Key features of achondroplasia, DMD and OI
Disease, features | Achondroplasia | Duchenne muscular dystrophy | Osteogenesis imperfecta |
|---|---|---|---|
Orphanet number and synonyms | ORPHA 15 | ORPHA 98896 | ORPHA 666 |
Prevalence | 4/100,000 | 30/100,000 males | 10/100,000 |
Genetic defect | Change in the DNA for fibroblast growth factor receptor 3 (FGFR3), which causes an abnormality of cartilage formation | Absence of the protein dystrophin in skeletal muscle, myocardium, and brain | Mutation in gene encoding collagen type I; deficiencies in proteins that interact with collagen (CRTAP, P3H1, PPIB, Serpin H1 and FKBP10) |
Mode of transmission | Autosomal dominant | X-linked recessive | Primarily autosomal dominant, although recessive cases reported |
Clinical symptoms | Short stature | Progressive weakness, contractures, spinal deformity, restrictive lung functional pattern, and cardiomyopathy | Increased bone fragility; fractures |
Cognitive impairment | None noted | Some variable degree of cognitive involvement | None noted |
Diagnosis | Neonatal; Prenatal in USA | Childhood | Variable |
Lifespan | Unimpaired | Death in early adulthood | Variable (unimpaired in types I, and IV), possibly somewhat decreased in type III) [81] |