Background & Aims: Aplasia Cutis Congenital (ACC) is the most common benign isolated defect but it can be associated with other physical anomalies or malformation and syndromes. No unifying theory can account for all lesions of ACC. Because this condition is the phenotypic result of more than one disease process it is likely that more than one mechanism is involved. Mechanisms include genetic factors, teratogens, compromised vasculature to the skin, and trauma. Frieden created a classification system for ACC consisting of 9 groups based on number and location of acc and the presence or absence of associated malformations¹.

Materials & Methods: In this observational cross-sectional study, a census method for gathering information was used. The obtained data were analyzed descriptively via EP16 software. we have studied 20 newborns, 9 males, and 11 females with skin defects, from September 1997 to September 2005 in Akbarabadi hospital.

Results: In this study, the skin lesions of 85% were single, 65% on the scalp, 50% on the vertex, 5% on parietal, 15% on parietoocciputal, 15% on lumbosacral, 20% on extremities, and 15% with trisomy13. Mothers of two newborns had the history of drug use and abuse during pregnancy. Extensive skin lesions during neonatal period have high mortality rate, in our study also the rate of mortality with extensive lesions were 55%.