Bone Dysplasia
Abnormal development Types Proportionate eg mucopolysaccharidoses Definition of Dysplasia Proportionate eg mucopolysaccharidoses Abnormal development Types Proportionate dysplasia / dwarfism Disproportionate Short trunk eg Kniest syndrome Short limb Proximal – rhizomelic Middle – mesomelic Distal – acromelic
Abnormal development Types Definition of Dysplasia Disproportionate Proportionate dysplasia / dwarfism Disproportionate Short trunk eg Kniest syndrome Short limb Proximal – rhizomelic Middle – mesomelic Distal – acromelic
Abnormal development Types Definition of Dysplasia Disproportionate Proportionate dysplasia / dwarfism Disproportionate Short trunk eg Kniest syndrome Short limb Proximal – rhizomelic Middle – mesomelic Distal – acromelic
Abnormal development Types Definition of Dysplasia Disproportionate Proportionate dysplasia / dwarfism Disproportionate Short trunk eg Kniest syndrome Short limb Proximal – rhizomelic Middle – mesomelic Distal – acromelic
Abnormal development Types Definition of Dysplasia Disproportionate Proportionate dysplasia / dwarfism Disproportionate Short trunk eg Kniest syndrome Short limb Proximal – rhizomelic Middle – mesomelic Distal – acromelic
Classification based on growth plate Hyperplasia Hypoplasia Epiphysis Physis Hyperchondroplasia Enchondromatosis Metaphysis Exostosis Diaphyseal Progressive diaphyseal dysplasia Epiphysis Spondyloepiphyseal dysplasia Multiple epiphyseal dysplasia Physis Achondroplasia Metaphysis Hypophosphatasia Osteopetrosis Diaphyseal OI and osteoporosis
Conditions Head Limbs Spine Achondroplasia Clinically Disproportionate dwarfism (most common type)– short limb AD FGFR 3 mutation Pseudoachondroplasia normal facies AD chromosome 19 defect on COMP Affects endochondral > appositonal growth Physeal dysplasia Head Button noses and frontal bossing Limbs Rhizomelic – N sitting height Trident hands Radial head subluxation Spine Lumber stenosis Thoracolumber stenosis
Conditions Involves the spine caused by Defect in Type 2 collagen Spondyloepeiphyseal dysplasia Mulitiple epiphyseal dysplasia (MED) Involves the spine caused by Defect in Type 2 collagen Congenital type = AD Tarda type = X-linked Scoliosis – sharply curved Mutation in COMP Delayed ossification / irregular epiphyses Clinically limb abnormalities Short MC and MT Valgus knees Irregular proximal femora
Conditions Epiphyseal osteochondromata Kniest Syndrome Dysplasia Epiphysealis Hemimeilica (trevors disease) AD defect in collage type II Short trunk disproportionate dwarfism Clinically Orthopaedic Contractures/stiffness Scoliosis and kyphosis Dumbbell femora Extra-skeletal Otitis media and hearing loss Epiphyseal osteochondromata Calcifications also seen within joint Usually only affects 1 joint
Conditions Affects proliferative and hypertrophic zones of physis Metaphyseal Chondrodysplasia Mucopolysaccharidosis Affects proliferative and hypertrophic zones of physis Types Jansen – AD defect to parathyroid related hormone Wide eyes and wide based stance (monkey) Schmid – AD type X collagen DD rickets with varus knees (N bloods) McKusick – AR cartilage hair dysplasia Fibular overgrowth and C1/2 instability Proportionate dwarfism with presence of complex sugars in the urine Types Morquio – AR keratin sulphate in urine C1/2 instability, cloudy cornea, waddling gait, valgus knees Hurler – AR heparan/dermatan sulphate Most severe form with mental retardation Hunter - heparan/dermatan sulphate Sanilippo - heparin sulphate