The size of the lesion is variable and may range from solitary round hairless patches to complete exposure of the cranial contents.

[3] The severity of the condition can vary between family members, suggestive of variable expressivity and reduced penetrance of the disease-causing allele.

Similar terminal transverse limb anomalies and cardiovascular malformations are seen in animal models of hypoxic insults during the first trimester.

[14][15] More recently, mutations in six genes have been identified, highlighting the Rho family of GTPases and the Notch signalling pathway as important factors in the pathogenesis of AOS.

[citation needed] Management of AOS is largely symptomatic and aimed at treating the various congenital anomalies present in the individual.

However, individuals with more severe scalp and cranial defects may experience complications such as hemorrhage and meningitis, leading to long-term disability.

[18] AOS was first reported by the American pediatric cardiologist Forrest H. Adams and the clinical geneticist Clarence Paul Oliver in a family with eight affected members.