Amelia And Terminal Transverse Hemimelia

Most cases are sporadic. Some families have affected relatives, suggesting a complex genetic etiology.

Bermejo-Sanchez et al. (2011) described the epidemiology of congenital amelia using data gathered from 20 surveillance programs on congenital anomalies, all International Clearinghouse for Birth Defects Surveillance and Research members, from all continents but Africa, from 1968 to 2006, depending on the program. Reported clinical information on cases was thoroughly reviewed to identify those strictly meeting the definition of amelia. Those with amniotic bands or limb-body wall complex were excluded. The primary epidemiologic analyses focused on isolated cases (about one-third) and those with multiple congenital anomalies (MCA) (two-thirds). A total of 326 amelia cases were ascertained among 23,110,591 live births, stillbirths, and, for some programs, elective terminations of pregnancy for fetal anomalies. The overall total prevalence was 1.41 per 100,000 (95% confidence interval 1.26-1.57). Only China, Beijing, and Mexico RYVEMCE had total prevalences, which were significantly higher than this overall total prevalence. Some underregistration could have influenced the total prevalence in some programs. Liveborn cases represented 54.6% of the total. Among monomelic cases (representing 65.2% of nonsyndromic amelia cases), both sides were equally involved, and the upper limbs (53.9%) were slightly more frequently affected. One of the most interesting findings was a higher prevalence of amelia among offspring of mothers younger than 20 years. Sixty-nine percent of the cases had MCA or syndromes. The most frequent defects associated with amelia were other types of musculoskeletal defects, intestinal defects, some renal and genital defects, oral clefts, defects of cardiac septa, and anencephaly.