A one-year old child is discovered to have numerous bone fractures. Social workers suspect
child abuse. What condition might lead to a false conclusion about this child? Explain what
causes this developmental disorder. How common is it?
Solution
Several fractures in various stages of healing of a child is not always a case of child abuse but it
may be a genetic disorder called osteogenesis imperfecta.
The disease follows autosomal dominant pattern of inheritance generally, But in some cases it
may follow autosomal recessive pattern of inheritance. There are eight recognized forms of
osteogenesis imperfecta.
Causes-- Mutations in the COL1A1 and COL1A2 genes causes the disease in 90% of cases.
CRTAP and P3H1 genes also cause osteogenesis imperfecta. These genes are responsible for
Type I collagen assembly. Type I collagen I required in formation and strengthening of
connective tissues, particularly bones. Due to the mutation collagen triple helix is denatured. As
a result the bones become fragile. Type I OI, which is a milder form, are characterized by bone
fractures during childhood and adolescence and this type occurs due to mutation in the COL1A1
gene. More severe forms of osteogenesis imperfecta (type II and type III) have no family history
and caused by sporadic mutations in the COL1A1 or COL1A2 gene.
More researches are still in progress to know more details (others genes that are involved,
alternative cause, treatment of the disease) about the disease.
Frequency—According to NIH report the disease is found in 6 to 7 per 100,000 people
worldwide. Types I and IV are the most common forms of osteogenesis imperfecta, affecting 4
to 5 per 100,000 people..
A one-year old child is discovered to have numerous bone fractures. S.pdf
1. A one-year old child is discovered to have numerous bone fractures. Social workers suspect
child abuse. What condition might lead to a false conclusion about this child? Explain what
causes this developmental disorder. How common is it?
Solution
Several fractures in various stages of healing of a child is not always a case of child abuse but it
may be a genetic disorder called osteogenesis imperfecta.
The disease follows autosomal dominant pattern of inheritance generally, But in some cases it
may follow autosomal recessive pattern of inheritance. There are eight recognized forms of
osteogenesis imperfecta.
Causes-- Mutations in the COL1A1 and COL1A2 genes causes the disease in 90% of cases.
CRTAP and P3H1 genes also cause osteogenesis imperfecta. These genes are responsible for
Type I collagen assembly. Type I collagen I required in formation and strengthening of
connective tissues, particularly bones. Due to the mutation collagen triple helix is denatured. As
a result the bones become fragile. Type I OI, which is a milder form, are characterized by bone
fractures during childhood and adolescence and this type occurs due to mutation in the COL1A1
gene. More severe forms of osteogenesis imperfecta (type II and type III) have no family history
and caused by sporadic mutations in the COL1A1 or COL1A2 gene.
More researches are still in progress to know more details (others genes that are involved,
alternative cause, treatment of the disease) about the disease.
Frequency—According to NIH report the disease is found in 6 to 7 per 100,000 people
worldwide. Types I and IV are the most common forms of osteogenesis imperfecta, affecting 4
to 5 per 100,000 people.
