Genetics of Skin Color Flashcards
Skin color is a combination of ___, ___ __, ___ tissue, and ___
Keratin, blood vessels, adipose, pigment
____ is when babies feet are blue right after birth
Acrocyanosis
Twins can also have blood supply not evening distributed and one looks much more red called ____ due to ____. Or they don’t get enough blood and appear pale or ____ due to anemia
Plethora
Polycythemia
Pallor
____ affects your hemoglobins ability to retain oxygen and changed skin color
Methemoglobinemia
___ ___ is shown with a grey/blue tongue
Central cyanosis
____ creat and distribute pigment. These cells appear to have almost a halos around them. ____ and ___ ___ hold onto the pigment
Melanocytes
Keratinocytes
Hair follicles
___ ___ are the cells that the melanocytes contact and deliver pigment to, usually 30 to 40 keratinocytes
Epidermic melanounis
Melanocytes are derived from the ___ ___ cells and migrate to the skin, eye, and heart.
Neural crest
Pigment production in melanocytes:
Golgi creates ____ enzyme and ____ where melanin is synthesized, stored, and transported. Tyrosine gets converted to by tyrosinase to ___ which gets made into polymers. These polymers turn into different types of melanin.
Tyrosinase
Melanosomes
DOPA
____ is black and ____ is more yellow or red. Humans have both kinds. They both function to protect DNA from UV radiation
Eumelanin
Pheomelanin
Melanin protects cells by interfering with ___ ___ production. They also interfere with physical ____ DNA damage
Free radical
Chemical
Picture of melanin hats:
Normal skin variants related to pigment:
Melanonychia striata:
Normal skin changes, multiple nails, but could have Pathologic entities that look similar
____ ____: autosomal recessive, inability to produce melanin. Increases risk of sunburn and skin cancer.
Oculocutaneous albinism
Darker skin blocks more ___ ___ and depends on global location. Where UV radiation is low, it’s advantageous to allow more UV to reach the skin to allow more ___ __ production. Where UV radiation is high, block UV to the skin to prevent ___ ___ and __ ___.
UV radiation
Vitamin D
Folate destruction
Skin cancer
Skin color is a ___ ___. Over 20 genes have been associated with variation in skin color.
Polygenic trait
Most of the genetic variation in human skin tone is non-coding or ___ rather than changes that affect protein sequence. A few polymorphisms do affect protein sequence.
Synonymous
Absent pigment due to auto antibodies attacking melanocytes
Vitiligo
Vitiligo diagnosis:
___ ___ is a type of UV light to detect depigmented areas of the skin, appear fluorescent. The lesions ___ ___, important distinguishing feature. Often time family history as well. Hair can be affected too.
Woods lamp
Lack scale
There was a prior ____ and after resolution there is now less pigment. Generally ___ defined lesions.
Inflammation
Poorly
Type of post inflammatory hypopigmentation. Involves face, upper body. Usually in younger children with darker skin. Asymptomatic. Poorly defined. Not caused by topical steroid use.
Pityriasis alba
Hypopigmented on lighter skin. The lesions do have scale. Shimmery feature. It likes moist areas.
Tinea versicolor
Tinea versicolor has ___ ___ lesions especially at the edges. They are rounded and oval
Fine scale
Tinea versicolor key features:
Multiple macules with fine powdery scale. Appears on upper arms, back, upper chest, and sometimes face. KOH scraping with “spaghetti and meatballs”
Inappropriately Increased melanogenesis. Gets worse in the sun.
Post-inflammatory hyperpigmentation
Melasma
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