Micromelia

Dysmelia (from the Greek (), "bad" + (), "limb" + English suffix -ia) is a congenital disorder of a limb resulting from a disturbance in embryonic development.

Types

Dysmelia can refer to

• missing (aplasia) limbs: amelia (including tetraamelia), 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: hemimelia, symbrachydactyly

Occurrence rate

Birth defects involving limbs occur in 0.69 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

Syndromes with dysmelia

• 2p15-16.1 microdeletion syndrome
• Achard syndrome
• Ackerman syndrome
• Acrocallosal syndrome
• Acropectoral syndrome
• Adams–Oliver syndrome
• Aglossia adactylia
• Amniotic band syndrome
• Apert syndrome
• Autosomal recessive Robinow syndrome
• Basel–Vanagaite–Sirota syndrome (Microlissencephaly-Micromelia syndrome)
• Campomelic dysplasia
• Cardiofaciocutaneous syndrome
• Catel–Manzke syndrome
• Cenani–Lenz syndrome
• Corneodermatoosseous syndrome
• Diploid triploid mosaic
• Ectrodactyly–ectodermal dysplasia–cleft syndrome
• Edwards syndrome
• Ellis–Van Creveld syndrome
• Fibular dimelia diplopodia syndrome (Leg duplication mirror foot syndrome)
• Greig cephalopolysyndactyly syndrome
• Haas syndrome
• Hanhart syndrome
• Holt–Oram syndrome
• Humeroradial synostosis
• Johnson–Munson syndrome
• Joubert syndrome
• McKusick–Kaufman syndrome
• Mermaid syndrome
• Mesomelia-Synostoses syndrome (8q13 microdeletion syndrome)
• Microgastria
• Myhre syndrome
• Nager acrofacial dysostosis
• Neu–Laxova syndrome
• Patau syndrome
• Pfeiffer syndrome
• Poland syndrome
• Radial aplasia
• Roberts SC-Phocomelia syndrome (Phocomelia syndrome)
• Rubinstein–Taybi syndrome
• Silver–Russell syndrome
• Split-hand split-foot malformation (SHFM)
• TAR syndrome (thrombocytopenia with absent radius)
• Tetra-amelia syndrome
• Ulbright–Hodes syndrome
• VACTERL association
• Wallis–Zieff–Goldblatt syndrome

References

External links

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