Congenital Upper Limb Anomalies 173Using the OMT classification, “malformations” was found to be the most
prevalent CULA category in Sweden (Ekblom et al., 2014) and also in
midwestern United States (Goldfarb et al., 2015). Epidemiological data from
Finland (Koskimies et al., 2011), Sweden (Ekblom et al., 2010), and Western
Australia (Giele et al., 2001) show that males are more likely affected than
females. Bilateral malformations were more common than malformations
affecting either the left or right sides (Ekblom et al., 2014). The most common
diagnoses in the midwestern states of the US were trigger digits and multiple
hereditary exostoses (Goldfarb et al., 2015), whereas in Sweden the most
common diagnoses were trigger digits and ulnar polydactyly (Ekblom et al.,
2014).
Congenital anomalies can be categorized as “isolated” when only the limb
is involved or “associated” when one or more additional major malformations
are present. Of infants born with multiple congenital anomalies, the most
common disorder associated with limb malformations is the VACTERL
(Vertebral anomalies, Anal atresia, Cardiac malformations, Tracheo-
Esophageal fistula, Renal anomalies, and Limb abnormalities) association
(Robert et al., 1997; Stoll et al., 2010). The most prevalent organ system
reported with limb reduction defects is the cardiac system (Robert et al., 1997;
Rosano et al., 2000; Stoll et al., 2010) followed by the urogenital, central
nervous, and digestive systems (Stoll et al., 2010).
RISK FACTORS
In many cases, the precise etiology of CULA is unclear or unknown.
There are however a variety of risk factors that predispose an embryo to
developmental anomalies. These fall into two large categories: Genetic and
Epigenetic/Environmental.
Genetic Contributions
The molecules involved with limb development are the key targets of
genetic disruption, although disruption of generalized growth and development
may also manifest with associated limb abnormalities. The molecules involved
with limb development are the key targets of genetic disruption, although
disruption of generalized growth and development may also manifest with
associated limb abnormalities.