Table 2.

Representative disorders of the growth plate

Syndrome	Defect	Zone involved	Manifestations
Campomelic dysplasia	SOX9 gene defect	Proliferative	95% mortality in neonatal period; scoliosis, kyphosis, short limbs
Achondroplasia	Fibroblast growth factor receptor defect	Proliferative	Dwarfism
Spondyloepiphyseal dysplasia (SED)	COL2A1 gene, produces type II collagen	Proliferative	Dwarfism, short trunk and neck, severe near-sightedness
Achondrogenesis type II	COL2A1 gene, produces type II collagen	Proliferative	Long bones do not ossify; generally fatal before puberty
Hypochondrogenesis	COL2A1 gene, produces type II collagen	Proliferative	Similar to achondrogenesis type II; spinal deformities less severe
Kniest dysplasia	COL2A1 gene, produces type II collagen	Proliferative	Dwarfism; kyphoscoliosis, arthritis, blindness
Stickler syndrome	Mutations in the COL11A1, COL11A2, COL2A1 genes, produce type II and XI collagen	Proliferative	Mild to severe, short stature, atypical facies, arthritis
Pseudoachondroplasia	Mutation in the gene encoding cartilage oligomeric matrix protein (COMP)	Prehypertrophic	Growth retardation starting age 2–3; short limbs; gait abnormalities
Multiple epiphyseal dysplasia (MED) (Fairbank’s disease)	Mutation in genes encoding COL9A1, COL9A2, COL9A3, COMP, MATN3	Prehypertrophic	Fatigue, waddling gait, very small ossification centres, short stature
Brachydactyly type A1	Numerous subtypes; mutation in Ihh gene	Prehypertrophic	Short fingers; some have absent ulna
Acrocapitofemoral dysplasia	Mutation in Ihh gene	Prehypertrophic	Short stature of variable degrees with short limbs, brachydactyly, narrow thorax
Cleidocranial dysplasia (CCD)	Mutation in RUNX2 gene	Hypertrophic	Growth retardation before, defective growth of skull bones; complete or partial absence of clavicles, thumbs

Note. Ihh, Indian hedgehog.