Dysmelia

Dysmelia (from Greek Δύσ - = "bad" plus μέλος (plural μέλεα) = "limb") is a congenital disorder referring to the limbs. ^[1]

Types

Dysmelia can refer to

• missing (aplasia) limbs: amelia, oligodactyly, congenital amputation
• malformation of limbs: ectrodactyly, phocomelia, meromelia, syndactyly, brachydactyly, clubfoot
• too many limbs: polymelia, polydactyly, polysyndactyly

Occurrence rate

Birth defects involving limbs occur in 1 per 1000.

Causes

Dysmelia can be caused by

• 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

References