Human Hereditary Project: Albinism
By: Madeleine Richards
First of all ---- Who is at risk for Albinism?
Albinism is an inherited disorder that’s present at birth. Children are at risk of being born with albinism if they have parents with albinism, or parents who carry the gene for albinism.
Other Names for Albinism
- oculocutaneous albinism
- OCA
- oculocutaneous
Types of Albinism
Type 1
- Characterized by white hair, very pale skin, and light-colored irises.
Type 2
- Type 2 is less severe than type 1. Usually the person has skin that is a creamy white with light brown or blond hair.
Type 3
- Called rufous oculocutaneous albinism. This usually affects darker-skinned people. These individuals have reddish-brown skin, ginger or red hair, and hazel or brown irises.
Type 4
- has signs and symptoms similar to those seen with type 2.
Hermansky-Pudlak syndrome
- Common in Puerto Rico. People with this syndrome range from being very pale to having normal coloring.
Chediak-Higashi syndrome
- The hair is usually brown or blond with a silvery sheen, and the skin is usually creamy white to grayish.
Type 1
Tyrosinase is the only gene in which mutations are known to cause oculocutaneous albinism type 1
Type 2
OCA2 is the only gene in which mutations are known to cause oculocutaneous albinism type 2.
Type 3
TYRP1 mutations cause type 3; and changes in the SLC45A2 gene result in type 4.
ty·ros·i·nase
an enzyme occurring in many organisms that is a catalyst in the conversion of tyrosine to the pigment melanin; inactivity of this enzyme results in albinism
Symptoms
Symptoms for all types of Albinism
- Rapid, involuntary back-and-forth movement of the eyes called nystagmus
- Inability of both eyes to stay directed at the same point or to move in unison (strabismus)
- Extreme nearsightedness or farsightedness, causing glasses to be needed
- Sensitivity to light, which is called photophobia
- Abnormal curvature of the front surface of your eye or the lens inside your eye (astigmatism), which causes blurred vision
Special Symptoms
Hermansky-Pudlak syndrome
- People with this disorder have signs and symptoms similar to people with oculocutaneous albinism, but they may also develop lung and bowel diseases, or a bleeding disorder.
Chediak-Higashi syndrome
- Has signs and symptoms similar to oculocutaneous albinism. People with this syndrome have a defect in white blood cells that increases their risk of infections.
Population
According to the US National Library of Medicine, an estimated 1 in 20,000 people worldwide are born with oculocutaneous albinism.
- Type 2 occurs most frequently in African Americans and people from sub-Saharan Africa
- Type 3 occurs most frequently in people from southern Africa.
- Type 4 occurs frequently in the Japanese and Korean populations.
Inheritance
Albinism is linked to the X chromosome and is autosomal recessive.
Can people diagnosed with Albinism still have children?
Yes.
There are Prenatal tests that can be done to see if a fetus has albinism.
Medical Assistance
There is no cure for albinism. Treatment for albinism can relieve symptoms and prevent sun damage. Treatment may include:
- sunglasses to protect the eyes from UV rays
- protective clothing and sunscreen to protect the skin from UV rays
- prescription eyeglasses to correct vision problems
- surgery on the muscles of the eyes to correct abnormal eye movements
Medical Advances on Albinism
Albinism is no longer a clinical diagnosis. The past classification of albinism was predicated on phenotypic expression, but now molecular biology has defined the condition more accurately. With recent advances in molecular research, it is possible to diagnose many of the various albinism conditions on the basis of genetic causation.
Future Outlook on Albinism
Scientists are currently working on trying to prevent the mutations in the genes that cause Albinism.