Adams-Oliver syndrome (AOS) is an extremely rare inherited disorder characterized by defects of the scalp and abnormalities of the fingers, toes, arms, and/or legs. The physical abnormalities associated with this disorder vary greatly among affected individuals. Some cases may be very mild while others may be severe. In infants with Adams-Oliver syndrome, scalp defects are present at birth (congenital) and may include one or multiple hairless scarred areas that may have abnormally wide (dilated) blood vessels directly under the affected skin. In severe cases, an underlying defect of the bones of the skull may also be present. In addition, infants with this disorder typically have malformations of the hands, arms, feet, and/or legs. These range from abnormally short (hypoplastic) fingers and toes to absent hands and/or lower legs. In some cases, additional abnormalities may also be present. Most cases of AOS appear to follow autosomal dominant inheritance but autosomal recessive inheritance has also been reported.