Table 1 Frieden’s classification of aplasia cutis congenita

1. ACC located on the scalp with no other anomalies

2. ACC located on the scalp but with concomitant limb anomalies such as: limb malformations (Adams–Oliver syndrome), hypoplasia or aplasia of the distal phalanges, vascular malformations, fibromas, nipple and hair abnormalities

3. ACC of the scalp along with epidermal nevi, neurological, and ophthalmic abnormalities (such as seizures, mental impairment, corneal and eyelid lesions)

4. ACC accompanied by embryologic deformities: such as omphalocele, leptomeningeal angiomatosis, cranial stenosis, porencephaly, meningomyelocele, spinal dysraphism, or gastroschisis

5. ACC along with fetus papyraceous, placental infarct; extensive ACC of the trunk or limbs

6. ACC and epidermolysis bullosa involving the lower extremities

7. ACC with no epidermolysis bullosa involving the extremities

8. Teratogen-associated ACC: herpes simplex and varicella-zoster virus intrauterine infections, and drugs during pregnancy such as methimazole or carbimazole

9. ACC accompanied by congenital malformations [Patau syndrome (trisomy 13), Wolf–Hirschhorn (4p deletion), Setleis syndrome, Johanson–Blizzard syndrome, Goltz syndrome, ADAM complex, Kabuki syndrome, Delleman syndrome, Finlay–Mark syndrome, XY gonadal dysgenesis]