Albinism, Oculocutaneous, Type V
Patient Information
Characteristics
Background and History
Albinism results from a lack of pigmentation most evident in the hair, skin, and eyes. The condition 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. This type (V) has so far only been identified in 6 individuals
Clinical Correlations
This type of albinism can be detected at birth based on the golden hair color and light skin pigmentation. Affected individuals have poor vision and roving eye movements (nystagmus). They are highly sensitive to light and the eyes have reduced pigmentation in the iris (that forms the pupil) and in the retina.
Except for the golden-colored hair and the white skin, no systemic anomalies have been reported.
Genetics
Inheritance
This is an autosomal recessive disorder caused by paired mutations in a gene which requires that both normally pigmented parents carry a single mutation. Such parents have a risk of 25% that each of their children will be albinos of this type. The specific gene responsible for this type of albinism has not been identified.
Pedigree
Autosomal recessive
In order for autosomal recessive disorders to be expressed, offspring generally must inherit two mutations, one from each carrier parent. Carriers with only one mutation, such as the parents, do not have clinical disease. Note that carrier parents can expect that 1 in 4 children (25%) will inherit both mutations and have the disorder, 2 in 4 children (50%) will be carriers like their parents, while 1 in 4 children (25%) inherit neither mutation.
In order for autosomal recessive disorders to be expressed, offspring generally must inherit two mutations, one from each carrier parent. Carriers with only one mutation, such as the parents, do not have clinical disease. Note that carrier parents can expect that 1 in 4 children (25%) will inherit both mutations and have the disorder, 2 in 4 children (50%) will be carriers like their parents, while 1 in 4 children (25%) inherit neither mutation.
Diagnosis and Prognosis
The golden hair color and white skin are present at birth. Dermatologists and ophthalmologists might collaborate on the diagnosis. There is no treatment for the pigmentation abnormalities but patients could benefit from the use of tinted glasses.
Longevity is most likely normal.
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