Amelia
Amelia refers to a skeletal dysplasia characterized by the complete agenesis of an upper or lower extremity or all four limbs. It may be associated with other congenital anomalies, i.e. omphalocele and diaphragmatic hernias .
Epidemiology
Amelia is a very rare congenital anomaly with an incidence rate of 0.04-0.15 per 10000 live births .
Associations
Such type of limb anomalies are associated with:
- thalidomide exposure - thalidomide embryopathy
- Roberts syndrome
Pathology
The arrest in the formation of primordial limb bud(s) during the early phase (before the 8th week of gestation) of embryogenesis, may be due to some mechanical, vascular insult or teratogenic exposure.
Radiographic features
Antenatal ultrasound
Antenatal ultrasound may be able to diagnose amelia especially after the latter half of the first trimester as a gross absence of one or more limbs with associated other anomalies.
Prognosis and treatment
The prognosis depends upon the severity of other associated anomalies. More than 60% of newborns die early postnatally due to complicated amelia .
Differential diagnosis
Imaging differential considerations include :
