Gourt Home::Gourt :: Mongolian spot
The term Mongolian Spot(s) or Mongolian Blue Spot refers to smooth brown or blue-gray birthmarks usually on the lower back and buttocks area of normal infants. It may look somewhat like a rash. It normally vanishes three to five years after birth.
Mongolian spot(s) is a congenital developmental condition exclusively involving the skin. Usually, it covers in spots or in one large patch one or all of the following: the lumbosacral area, the buttocks, flanks, and shoulders. It results from the entrapment of melanocytes in the dermis during the course of their migration from the neural crest to the epidermis during embryonic development. The condition is not linked to sex, and both male and female infants are equally predisposed to Mongolian Spot(s). It is associated with cleft lip, spinal meningeal tumor, melanoma, and phakomatosis pigmentovascularis but in general is perfectly harmless.
Mongolian Spot(s) is most common among Mongols and other Asian ethnic groups: (Japanese, Indonesians, Koreans, Usbekistanis, Turkmenistanis, Turks, Malaysians, Chinese, Mongols, etc.) Nearly all Mongolian infants are born with one or more Mongolian Spot. 95-100% of East Asian and Native American infants, 40-50% of Hispanic infants, and very few Caucasian and other infants have it. It is also very common if only one of the parents is East Asian.
It might sometimes be mistaken for abuse bruises.
from the Mōkohan article
A Mōkohan (Mongolian spot) is a bluish spot on the lower back of Asian infants and babies. The blue colour is caused by Melanin-containing cells—Melanocytes—that are deep under the skin. The spots usually disappear in a few years and almost always by puberty. In Japan, these spots led to an idiom "his butt is blue" ("shiri ga aoi"), which means a person is childish.
References
- Japan SAQ - seldom asked questions about Japan
- Mongolian Spot - English information of Mongolian spot, written by Hironao NUMABE, M.D., Tokyo Medical University.
"Mongolian spot"