Types of OI

Question 1

Type I

Answer 1

MILD, lifelong blue sclera, autosomal dominant, normal or near normal stature, generalized osteoporosis, joint hyperlaxity, presenile conductive hearing loss
50% of cases
IA: normal teeth
IB: dentinogenesis

Question 2

Type II

Answer 2

MOST SEVERE, lethal, autosomal dominant, tinted sclera
NOT COMPATIBLE WITH LIFE
Extreme bone fragility
Infants small for GA, short, curved and deformed limbs
Lack of ossification in skull and facial bones

Question 3

Type III

Answer 3

SEVERE, normal sclera, autosomal dominant or recessive, very short stature, respiratory problems possible
Progressive deformity of long bones, skull, and spine
abnormal growth plate lines = long bones have popcorn appearance
severe bone fragility
bone deformity at birth, multiple fractures and severe growth retardation
dentinogenesis
Severe kyphoscoliosis = respiratory problems–> death may occur in childhood

45%

Question 4

Type IV

Answer 4

MODERATE, autosomal dominant, most fractures occur before puberty, near normal sclera, brittle teeth, short stature, hearing loss is variable

Question 5

Type V

Answer 5

moderate, bone has mesh-like appearance, autosomal dominant, white sclera, normal teeth
Hypertrophic ossification of fractures and surgical osteotomies
Calcification of interossesous membrane between radius and ulna
5%

Question 6

Type VI

Answer 6

moderate, autosomal dominant or recessive, bone has fish scale appearance
Extremely rare
normal teeth and sclera
no abnormality of minerals

Question 7

VII

Answer 7

moderate, recessive, short stature
Gene defect: 3p22-24.1
No Type I collagen defect-- defect involves how collagen is translated to create bone 
Normal sclera and teeth 
Moderate to severe bon fragility 
shortening of humerus and femur

Question 8

VIII

Answer 8

resembles types II and III, recessive, white sclera
Autosomal recessive- caused by mutations of genes that affect translation of collagen
Flattened long bones, slender ribs without beading, small to normal head circumference
Severe bone and growth deficiency

Question 9

OIC

Answer 9

OI Congenita: most severe and disabling
numerous fx at birth, dwarfism, bowing of long bones, blue sclera, denitinogenesis
poor prognosis- high mortality rate due resulting from IVH at birth and increased respiratory infections

Question 10

OIT

Answer 10

OI Tarda: more mild, fractures occur after birth
Subclassified based on severity of bowing of bones

Types I-VIII

Question 11

Types of OI

Answer 11

Types V-VIII = do not have type 1 collagen defect, do not have specific bone fragility