The goal of this research study is to identify genes and regulatory elements on chromosomes that cause ACC. The investigators also study tissue samples from patients to learn about the processes that lead to this disorder.

Aplasia cutis congenita (ACC) or congenital scalp defect is a very rare disorder that affects bone and skin. The definition for ACC is the localized absence of (normal) skin at the time of birth (congenital). The skin appears thinner and the underlying structures are visible. We study mostly the isolated form of ACC with the lesion often being at the vertex of the skull (at or close to the top of the skull). The bone underlying the lesion is sometimes thinner as well.

For this study we will:

• Send out study participation kits and consent by phone
• Collect a saliva sample from eligible individuals
• Obtain information regarding ACC
• Document disorder with photos and doctor's letters
• If patients undergo surgery for ACC we ask to obtain some tissue that would otherwise be discarded
• Isolate DNA from the saliva sample
• Perform genetic analyses of the DNA with the most up-to-date methods available to identify genetic variations
• Study in the laboratory why the genetic variations cause the disorder

Inclusion Criteria:

• ACC; unaffected individuals only if part of a participating ACC family

Exclusion Criteria:

• No ACC unaffected individuals only as part of a participating ACC family

Individuals with diagnosed ACC