Table 1.
Types of osteogenesis imperfecta (adapted from [18]).
| Type | Inheritance** | Clinical | Incidence++ | Mutations |
|---|---|---|---|---|
| I | AD | Mild, blue sclerae fractures with little or no deformity hearing loss, DI | 60% | Type I collagen COL1A1, COL1A2 |
| II | AD, AR | Lethal, pulmonary insufficiency, beaded ribs, rhizomelic hearing loss | 10% | Type I collagen COL1A1, COL1A2 |
| III | AD, AR | Progressive deforming intrauterine fractures, deformed limbs, scoliosis white or blue sclerae hearing loss, DI | 10% | Type I collagen COL1A1, COL1A2 |
| IV | AD | Moderately severe, limb deformity, sclerae blue early and lighten with age scoliosis | 15% | Type I collagen COL1A1, COL1A2 |
| V | AD | Variable phenotype like IV hyperplastic callus, dislocated radial head calcified interosseous membrane | 5% | Unknown |
| VI | unknown | More fractures than IV mineralization defect on biopsy, vertebral fractures, no DI | Unknown | Type I collagen SERPINF1 (chaperone protein) |
| VII | AR | First nations family, Quebec | ++ | CRTAP, LEPRE1, PPIB (prolyl-3 hydroxylation) |
| congenital fractures white sclerae, severe rhizomelia | ||||
| VIII | AR | Severe or lethal similar to OI type II (Sillence) | ++ | CRTAP, LEPRE1 SERPINH1 |
**AD = autosomal dominant.
**AR = autosomal recessive.
++: the incidence of OI types I–IV is reasonably established. However, for the less common types, OI types VI, VII, and VIII, the incidence is not clearly defined. However, it is estimated that the recessively inherited forms (VII and VIII) constitute approximately 3–5% of the total OI population.