Skeletal Dysplasia (Osteochondrodysplasias)

Intro

heterogeneous group of heritable disorders characterised by abnormalities of cart + bone growth, resulting in abnormal shape + size of the skeleton + disproportion of long bones, spine + head

Achondroplasia

Osteogenesis Imperfecta (Brittle Bone Disease)

Thanatophoric Dysplasia

AD inheritance, but 50% sporadic

short stature

short limbs

large head

frontal bossing

depression of nasal bridge

short broad hands

marked lumbar lordosis develops

hydrocephalus sometimes occurs

often no family hx

Group of disorders of collagen metabolism

Bone fragility, bowing, #s

Type 1

most common

AD

fractures during childhood

blue sclerae

some develop hearing loss

tx = bisphosphonates to reduce # incidence, splinting after #s to minimise joint deformity

Type 2

prognosis variable

severe, lethal

multiple #s present before birth

often stillborn

inheritance mostly AD or sporadic, paternal mosaicism has been noted too

in other types scleral discolouration may be minimal

may be wormian bones in skull (extra bones within skull sutures)

results in stillborn

large head, extremely short limbs, small chest

sporadic

may be identified on antenatal US

Cleidocranial dysostosis

AD

absence of part of/all of clavs

delay in ant fontanelle closure + ossification of skull

child can bring shoulders together in front of chest to touch each other

short stature usually present

intelligence normal

Arthrogryposis

heterogeneous group of congenital disorders

stiffness + contracture of joints

cause usually unknown

a/w oligohydramnios, widespread congenital abnormalities + chromo disorders

usually sporadic

flexion contractures in knees, elbows, wrists

dislocation of hips + other joints

talipes equinovarus

scoliosis

thin skin

reduced subcut tissue

marked muscle atrophy atrophy affected joints

intelligence unaffected

management

physio

splints

plaster casts

surgery

walking impaired in severe forms

Osteopetrosis (marble bone disease)

rare, severe

bones are dense but brittle

AR

FTT

recurrent infection

hypocalcaemia

anaemia

thrombocytopenia

poor prognosis

BM transplant can be curative

less severe AD form can present in childhood with #s

Marfan syndrome

AD

tall stature

long thin digits (arachnodactyly)

hyperextensible joints

high arched palate

upward dislocation of lenses

severe myopia

great distance between pubis + sole than pubis + crown

arm span > height

chest wall deformities

scoliosis

Degeneration of media of blood vessel walls

dilated incompetent aortic root

valvular incompetence (mitral valve prolapse + regurg)

aortic aneurysms may dissect/rupture

ECHO monitoring needed