Albinism (overview) E70.3

Albinism is the genetically determined absence of pigment. Clinically, it is a group of genetically different diseases characterized by generalized or partial hypomelanosis of skin, hair and eyes (oculocutaneous albinism - OCA) or only of the eyes (ocular albinism) (note: only albinism type IA and generalized vitiligo show a complete loss of pigment). It is based on a congenital, mostly autosomal recessive inherited disorder of melanin synthesis with normal intraepidermal melanocyte number.

The following entities can be distinguished:

• Oculocutaneous albinism (OCA types 1-7).
• Ocular albinism (dermatologically not relevant): 5 forms with different degrees of iris depigmentation. Additionally photophobia, possibly nystagmus, strabismus, hypoplasia of the fovea centralis.
• Other, rare, syndromic forms of albinism (also "albinoidism") with generalized, marked hypopigmentation and additional organ manifestations that are crucial for morbidity and prognosis:
  • Hermansky-Pudlak syndrome
  • Chédiak-Higashi syndrome
  • Cross syndrome
  • Griscelli syndrome

  • Primary immunodeficiency syndrome due to Lamtor2 defect

Albinism must be distinguished from piebaldism (called leucism in veterinary medicine), in which melanocytes are completely absent from depigmented areas due to gene mutations (mutations in the KIT (see kit below) and SLUG (SNAI2 - snail homolog 2 transcription factor) genes have been demonstrated (Saleem MD et al. 2019).

1. Böhm M (2015) Differential diagnosis of hypomelanosis. Dermatologist 66: 945-958
2. Bohn G et al (2007) A novel human primary immunodeficiency syndrome caused by deficiency of endosomal adaptor protein p14. Nature Med 13: 38-45.
3. Saleem MD et al (2019) Biology of human melanocyte development, Piebaldism, and Waardenburg syndrome. Pediatr Dermatol 36:72-84.
4. Schiefermeier N et al (2014) The late endosomal p14-MP1 (LAMTOR2/3) complex regulates focal adhesion dynamics during cell migration. J Cell Biol 205:525-540.