Adams-Oliver Syndrome (AOS) is a rare genetic disease characterized by aplasia cutis congenita (ACC) and terminal transverse limb defects (TTLD) with varying degrees of severity in each individual. Some patients may show very mild clinical features, while others may be severe. The prevalence of AOS is unknown. Variable clinical features are observed in different individuals, including malformations of the hands, arms, feet and/or legs that range from hypoplastic fingers and toes to absent hands and/or lower legs, and occasionally show intellectual deficit. Other physical anomalies may present in some AOS patients including congenital cataract, strabismus and microphthalmia, congenital heart malformations, and hepatoportal sclerosis.
Mutations in the DOCK6 gene, located on 19p13.2 chromosome, are the cause of the autosomal recessive form of ASO2. The protein encoded by DOCK6 gene is involved in the regulation of proteins called GTPases, which transmit signals that are critical for various aspects of embryonic development of the limbs, skull, and heart.
