4.1 Etiology
ACC was first reported by Gordon in 1767 and summarized by Campbell in
1826[6]. It is occurring mainly on the top of the
head but can occur anywhere on the body[5]. The
cause of ACC is unknown. Genetics and exogenous factors may play a role
in the development of the lesion. Suspected exogenous causes include
intrauterine trauma, localized amniotic adhesions, and exposure to
teratogenic substances such as antithyroid drugs, valproic acid,
marijuana, heroin, alcohol, and cocaine during
pregnancy[7]. The occurrence of ACC has also been
associated with skin tears due to excessive tension in the fetal skin
and subcutaneous tissues, with the top of the head being the most
tensioned area[8]. The only thing that has been
established is that the occurrence of congenital dermal dysplasia is
genetically related. Most of these lesions are disseminated, but
approximately 25% are autosomal dominant or recessive. Other genetic
abnormalities associated with congenital dermal dysplasia include
autosomal aberrations, deletions, trisomies and mutations.No identified
genetic target for ACC had been identified, but a recent study suggests
a possible role for the BMS1 gene. In a 2013 study that examined five
generations of autosomal dominant ACC, mutations in the BMS1 gene were
found to play an essential role in skin
morphogenesis[9]. ACC can also be associated with
various genetic syndromes such as ADAMS-Oliver syndrome, Bart syndrome,
and Setleis syndrome. There was no family history of genetic
predisposition or exposure to drugs and teratogenic substances during
pregnancy in both cases. The same point is that both are macrodome, and
it is considered that the fetus grew rapidly during pregnancy, causing
congenital skin dysplasia due to hypertonicity of the skin tissue on the
top of the head.