Albinism, Oculocutaneous, Type IV

Background and History: 

The condition known as albinism has been known since antiquity.  In fact, the biblical Noah is claimed by some to have been an albino.  Multiple types have been described and all are caused by mutations in genes that are involved in the synthesis of pigment. 

Clinical Correlations: 

This type of albinism is characterized by decreased pigmentation in the eyes, hair and skin.  There are secondary changes in the retinas (light sensing tissue) of the eye that lead to dysfunction of the rods and cones resulting in loss of vision.  The condition is present at birth as skin and hair are usually lightly pigmented but there is a wide range from white to brown.  The hair may darken slightly with age.  The colored part of the eye (iris) is generally grey-blue but may also darken slightly with age.  The normal color of the inside of the eye is not present and appears ‘blond’.  The eyes usually have a to-and-fro motion (nystagmus) beginning at birth or at least by 3-4 months of age.  They are unable to fixate on a target.  Depth perception is often defective.  Vision is stable in the range of 20/100 to 20/200.  Sensitivity to light (photophobia) is noted by many patients.

There is an increased risk of skin cancer from sun exposure. 

Genetics: 

Like other types of oculocutaneous albinism, this type is inherited in an autosomal recessive pattern.  Two mutations are required for the disease to be manifest.  These are acquired from carrier parents who each carry one copy.  Such parents can expect on average that one out of four of their children will inherit both copies from them and have albinism.  The parents do not have evidence of albinism. 

Diagnosis and Prognosis: 

The diagnosis is often made at birth based on the lack of hair and skin pigmentation.  An ophthalmological examination can help verify the diagnosis but gene studies are usually required to determine the type of albinism.  Life span is normal and the only restrictions to living a normal life come from the reduction in vision.  Low vision aids and tinted lenses can be helpful.  Sun exposure should be limited to reduce the risk of skin cancer. 

Additional Information
Inheritance/Pedigree: 
Autosomal recessive