How is osteogenesis imperfecta (OI) classified?

Updated: Feb 24, 2020
  • Author: Manoj Ramachandran, MBBS, MRCS, FRCS; Chief Editor: Harris Gellman, MD  more...
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Answer

The clinical presentation of OI is dependent on the phenotype. The most widely used classification has been that of Sillence, [16, 1] which classifies OI into four types on the basis of clinical and radiologic features (see Table 1 below). In addition, dentinogenesis imperfecta is denoted as subtype B, whereas OI without dentinogenesis imperfecta is denoted as subtype A.

Table 1. Adapted Sillence Classification of Osteogenesis Imperfecta (OI) (Open Table in a new window)

Type of OI 

Inheritance

Teeth

Bone Fragility

Bone Deformity

Sclera

Spine

Skull

Prognosis

IA

AD

Normal

Variable but less severe than other types

Moderate

Blue

20% scoliosis and kyphosis

Wormian bones

Fair

IB

AD

Dentinogenesis imperfecta

NA

NA

NA

NA

NA

NA

II

AD

Unknown

Very severe

Multiple fractures

Blue

NA

Wormian bones with absence of ossification

Perinatal death

III

AD

Dentinogenesis imperfecta

Severe

Progressive bowing of long bones and spine

Bluish at birth but white in adults

Kyphoscoliosis

Hypoplastic wormian bones

Wheelchair-bound, not ambulatory

IVA

AD

Normal

Moderate

Moderate

White

Kyphoscoliosis

Hypoplastic wormian bones

Fair

IVB

AD

Dentinogenesis imperfecta

NA

NA

NA

NA

NA

NA

AD = autosomal dominant; NA = not applicable.

Four more types of OI (types V, VI, VII, and VIII) have been described, [17] though they have not yet been incorporated into the International Classification of the Osteochondrodysplasias (INCO), which uses the Sillence classification. These forms are described further below.


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