A few conditions present in X-linked dominant form.  These conditions are generally only seen in girls as the mutations are usually lethal in developing boys who have only the affected copy of the X gene. Boys can rarely be affected if they have a post-zygotic mutation or have an XXY genotype.  In girls, the skin findings often present with lines/swirls that represent lyonization, the process by which one X chromosome is activated in any given cell.

Incontinentia pigmenti is caused by mutations in the NEMO gene, which helps to regular apoptosis. There are 4 phases of IP that occur in the skin in roughly sequential order, though the path is not entirely linear and conditions such as illness may shift the skin toward an “earlier” phase.

1.  Blistering
2. Verrucous plaques
3. Hyperpigmentation
4. Hypopigmentation