Congenital Disorders

Question 1

What disease is also known as ‘brittle bone disease’?

Answer 1

Osteogenesis imperfecta

Question 2

Where is the defect in osteogenesis imperfecta?

Answer 2

The synthesis or organisation of type I collagen which accounts for most of the composition of bone

Question 3

The majority of cases of osteogenesis imperfecta are inherited how? What does this mean?

Answer 3

Majority are autosomal dominant, usually this means they are milder cases

Question 4

What are some features of autosomal dominant inherited osteogenesis imperfecta?

Answer 4

Short stature with multiple deformities and fragility fractures, blue sclera and hearing loss

Question 5

Rare cases of osteogenesis tend to be more severe and are inherited how?

Answer 5

Autosomal recessive

Question 6

Give some features of autosomal recessive osteogenesis imperfecta?

Answer 6

Severe scoliosis and deformity, may be fatal in the perinatal period

Question 7

Osteogenesis imperfecta results in low energy fractures. What are some other causes of this which should be considered if a child has this presentation?

Answer 7

NAI or osteopenia (associated with prematurity)

Question 8

Most adults with osteogenesis imperfecta will have what?

Answer 8

Scoliosis

Question 9

The commonest form of skeletal dysplasia is what? How is this usually inherited?

Answer 9

Achondroplasia: can be autosomal dominant but >80% of cases are sporadic

Question 10

Describe achondroplasia?

Answer 10

Disproportionately short limbs, with a prominent forehead and wide nose. Joints are lax. Mental development is normal.

Question 11

How may very mild cases of osteogenesis imperfecta present?

Answer 11

With relatively normal x-rays but a history of low impact fractures

Question 12

What are the bones like in osteogenesis imperfecta? How do fractures heal?

Answer 12

The bones are very thin, gracile and osteopenic. Fractures heal with abundant callus.

Question 13

How are fractures related to osteogenesis imperfecta usually treated?

Answer 13

Splintage, traction or surgical stabilisation

Question 14

In severe cases, osteogenesis imperfecta can cause bowing of the bones which leads to stress fractures. How are these treated?

Answer 14

May need osteotomies and intra-medullary stabilisation

Question 15

What are skeletal dysplasias?

Answer 15

A group of genetic disorders (hereditary or sporadic) which lead to short stature which can be proportionate or disproportionate

Question 16

How does skeletal dysplasia cause a short stature?

Answer 16

Abnormal development of bone and connective tissue

Question 17

As well as short stature, what are some features of skeletal dysplasia that may or may not always be present?

Answer 17

Learning difficulties, deformities, hyper mobility, skin abnormalities, tumour formation, intrauterine/premature death

Question 18

What type of tumour is associated with skeletal dysplasia?

Answer 18

Haemangioma

Question 19

Treatment for skeletal dysplasia is supportive. Give some examples of this?

Answer 19

Preventing spinal cord and nerve compression, treating joint instabilities and deformities, limb lengthening

Question 20

What tests may be offered if a child has a skeletal dysplasia?

Answer 20

Genetic testing of the child and family

Question 21

Connective tissue disorders are generally disorders of what? What does this result in?

Answer 21

Mainly a disorder of type I collagen synthesis, resulting in joint hyper mobility

Question 22

What are the 4 main connective tissues? Embryologically, where do these come from?

Answer 22

Bone, cartilage, tendons and ligaments. These come from the mesoderm.

Question 23

In connective tissues, what is the exception which is mainly composed of type II collagen?

Answer 23

Articular (hyaline) cartilage

Question 24

How can Marfan’s Syndrome be inherited?

Answer 24

Sporadic or autosomal dominant

Question 25

Where is the mutation in Marfan's Syndrome? What is this required for?

Answer 25

Fibrillin gene- a scaffold for elastin

Question 26

What are the major features of Marfan's Syndrome?

Answer 26

Tall stature with disproportionately long limbs, hyper mobility (lax ligaments) and arachnodactyly

Question 27

What are some more specific features of Marfan's Syndrome?

Answer 27

High arched palate, scoliosis, pectus excavatum, spontaneous pneumothorax

Question 28

What are some ocular problems which Marfan's can cause?

Answer 28

Lens dislocation, glaucoma, retinal detachment

Question 29

Cardiac abnormalities may cause premature death in Marfan's Syndrome. What are some features?

Answer 29

Aortic aneurysms, valve incompetence (particularly mitral regurgitation)

Question 30

Why are joint dislocations a problem in Marfan's Syndrome?

Answer 30

Stabilisations do not work because the biological abnormality cannot be corrected

Question 31

Generalised familial joint laxity is normally inherited how?

Answer 31

Autosomal dominant

Question 32

People with generalised lax ligaments are more prone to what problems?

Answer 32

Soft tissue injury e.g. ankle sprain and recurrent dislocations of joints (especially shoulder and patella)

Question 33

Ehlor's Danlos Syndrome is usually inherited how? It involves defects in a number of genes involved in what?

Answer 33

Autosomal dominant: genes involved in collagen and elastin formation

Question 34

What are the main features of Ehlor's Danlos Syndrome?

Answer 34

Scoliosis, joint hypermobility and dislocations, vascular fragility and ease of bruising

Question 35

Stabilisation can be performed for dislocating joints in Ehlor's Danlos Syndrome. Why can this be a problem?

Answer 35

Can have issues with bleeding and wound healing can be poor

Question 36

Down's syndrome causes short stature and joint laxity which can predispose to what?

Answer 36

Recurrent dislocations (especially patella) and OA, atlanto-axial instability and spinal cord compression

Question 37

How are muscular dystrophies inherited? What does this mean?

Answer 37

X-linked recessive, hence they only affect boys

Question 38

Where is the defect in muscular dystrophy?

Answer 38

The dystrophin calcium gene

Question 39

What does muscular dystrophy lead to?

Answer 39

Progressive muscle weakness and wasting as the boy gets older

Question 40

What are some indications of / tests for muscular dystrophy?

Answer 40

Gower's sign, raised CK, muscle biopsy

Question 41

Children with muscular dystrophy will usually be unable to do what by age 10? What will then ensue?

Answer 41

Unable to walk by age 10. Then progressive respiratory and cardiac failure until death in the early 20s.

Question 42

What are some supportive treatments for muscular dystrophy?

Answer 42

Physiotherapy, splintage, deformity correction

Question 43

How is Becker's muscular dystrophy different to Duchenne?

Answer 43

Becker's is less severe, boys will usually be able to walk in their teens and will survive into 30s/40s

Question 44

When should children be screened for muscular dystrophy?

Answer 44

If there is a positive family history