Amelia refers to a skeletal dysplasia characterised by the complete absence of upper or lower extremity or all four limbs. It may be associated with other congenital anomalies, i.e. omphalocoele and diaphragmatic hernias 3.
Amelia is a very rare congenital anomalies with incidence rate of 0.04-0.15 per 10000 live births 1.
The arrest in formation of primordial limb bud(s) during early phase (before 8th week of gestation) of embryogenesis, may be due to some mechanical, vascular insult or teratogenic exposure.
Such type of limb anomalies are associated with 4:
Antenatal ultrasound may be able to diagnose amelia especially after the latter half of first trimester as gross absence of one or more limbs with associated other anomalies.
Prognosis and treatment
The prognosis depends up on the severity of other associated anomalies. More than 60% of newborns die early postnatally due to complicated amelia 2.
Imaging differential considerations include 2:
- sirenomelia (mermaid syndrome)
- other limb reduction defects
- 1. Froster-Iskenius UG, Baird PA. Amelia: incidence and associated defects in a large population. Teratology. 1990;41 (1): 23-31. doi:10.1002/tera.1420410104 - Pubmed citation
- 2. Nyberg DA, McGahan JP, Pretorius DH et-al. Diagnostic Imaging of Fetal Anomalies. LWW. (2003) ISBN:0781732115. Read it at Google Books - Find it at Amazon
- 3. Mastroiacovo P, Källén B, Knudsen LB et-al. Absence of limbs and gross body wall defects: an epidemiological study of related rare malformation conditions. Teratology. 1992;46 (5): 455-64. doi:10.1002/tera.1420460510 - Pubmed citation
- 4. Froster-Iskenius UG, Baird PA. Amelia: incidence and associated defects in a large population. Teratology. 1990;41 (1): 23-31. doi:10.1002/tera.1420410104 - Pubmed citation