Dysmelia

Piglet with dipygus at Ukrainian National Chernobyl Museum in Kiev

Dysmelia (from Gr. δυσ- dys, "bad" + μέλ|ος mél|os, "limb" + Eng. suff. -ia) is a congenital disorder of a limb resulting from a disturbance in embryonic development.

Types

Dysmelia can refer to

• missing (aplasia) limbs: amelia, oligodactyly, congenital amputation
• malformation of limbs: shortening (rhizomelia or mesomelia), ectrodactyly, phocomelia, meromelia, syndactyly, brachydactyly, club foot
• 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

External links

• DysNet: An organisation for people affected by Dysmelia (congenital limb difference)
• Reach: Association for Children with Upper Limb Deficiency)