Dysmelia (from the Greek dys (δυσ-), "bad" + mélos (μέλος), "limb" + English suffix -ia) is a congenital disorder of a limb resulting from a disturbance in embryonic development.^[1]

Types

Dysmelia can refer to^{[citation needed]}

• missing (aplasia) limbs: amelia, oligodactyly, congenital amputation e.g. tibial or radial aplasia
• malformation of limbs: shortening (micromelia, rhizomelia or mesomelia), ectrodactyly, phocomelia, meromelia, syndactyly, brachydactyly, club foot
• extra limbs: polymelia, polydactyly, polysyndactyly
• others: tetraamelia, hemimelia, symbrachydactyly

Occurrence rate

Birth defects involving limbs occur in 0,69 per 1000.^[2]

Causes

Dysmelia can be caused by^{[citation needed]}

• Inheritance of abnormal genes, e.g. polydactyly, ectrodactyly or brachydactyly, symptoms of deformed limbs then often occur in combination with other symptoms (syndromes)
• external causes during pregnancy (thus not inherited), e.g. via amniotic band syndrome
• teratogenic drugs (e.g. thalidomide, which causes phocomelia) or environmental chemicals
• ionizing radiation (nuclear weapons, radioiodine, radiation therapy)
• infections
• metabolic imbalance

Syndromes with dysmelia