Adams-Oliver syndrome (AOS), a rare inherited disorder, is characterized by scalp and terminal limb defects. Several genes associated with Notch pathway mutations have led to AOS. Here, we report a Thai male newborn presenting with aplasia cutis congenita and absence of a right pulmonary artery, which is suggestive of AOS. This was confirmed by the identification of a novel missense mutation in DLL4, a heterozygous one base pair change at nucleotide 82 (c.82G>C, p.Gly28Arg), which is in Nterminal domain. This is the first DLL4-related AOS case with arterial defect.