Delayed Maturation of Bone

Question 1

What is osteogenesis imperfecta?

Answer 1

Group of mainly AD disorders of connective tissue caused by mutations in the gene for type I collagen

Question 2

What mutations are responsible for osteogenesis imperfecta?

Answer 2

COL1A1 and COL1A2 on chromosome 17 and 7, respectively

Question 3

What types of OI are COL1A1 mutations seen?

Answer 3

All types of OI

Question 4

What types of OI are mutations in COL1A2 found?

Answer 4

Types II - IV

Question 5

What type of OI is the mildest phenotype?

Answer 5

OI type I

Question 6

What are the typical findings in a person with OI type I?

Answer 6

• Multiple fractures after birth
• Blue sclera
• Hearing Abnormalities

Question 7

What is the genetic inheritance and Px of OI type II?

Answer 7

Autosomal dominant; lethal

Question 8

WHat is the most severely deforming type of OI? What is it characterized by?

Answer 8

OI type III characterized by many bone fractures, growth retardation and severe skeletal deformities

Question 9

What are the characteristics of type IV OI? How is it different from type I?

Answer 9

Same as type I (multiple fractures after birth, hearing abnormalities) but NO blue sclera

Question 10

What is Ollier disease?

Answer 10

Multiple enchondromatosis - development of numerous cartilaginous masses that lead to bony deformities

Question 11

A patient has mutliple enchondromas and cavernous or spindle cell hemangiomas of the soft tissue. Dx?

Answer 11

Maffucci syndrome