Albinism

Heterogeneous group of hereditable diseases of the melanin pigmentary system.

Oculocutaneous Albinism

• Type IA = Tyrosinase negative albinism
• Type IB = Yellow mutant albinism
• Type IC = Platinum albinism
• Type II = Tyrosinase-positive albinism
• Type III = Minimal pigment albinism
• Type IV = Brown albinism
• Type V = Rufus albinism
• Type VIA = Hermansky-Pudlak syndrome (HPS)
• Type VIB = Chediak-Higashi syndrome
• Type VII = Autosomal dominant albinism

Ocular Albinism

• Type I = Albinism autosomal recessive
• Type II = Albinism Forsius-Ericksson syndrome
• Type III = Albinism with sensorineural deafness
• Type IV = Tietz syndrome

Type I is an autosomal recessive disorder that is associated with a defect in the gene encoding for tyrosinase. Most of the other types are either autosomal dominant or sex-linked variants and are believed to be tyrosinase positive. Albinism does exist in all racial groups.

Oculocutaneous albinism is caused by congenital melanin metabolism defects. The common defect linking all forms of albinism affects the formation of melanosomes. Melanin biosynthesis is initiated by the catalytic oxidation of tyrosine to dopa (3-4-dihydroxyphenylalanine, a melanin precursor) by tyrosinase. This reaction requires dopa as a cofactor. Albinos are either tyrosinase positive or negative, and all subtypes can be identified by clinical and biochemical means. The degree of melanin depletion is used to classify the disease into different subtypes.

Both ocular and cutaneous tissues are affected in this form of albinism, with diffuse leukodermia and variable pilosity disorders. The disease is potentially severe because patients may develop cutaneous carcinoma or melanoma with more or less early onset. Two types of oculocutaneous albinism have been identified, depending on the presence or absence of tyrosinase. The tyrosinase-negative form, also called complete albinism type I, is the most severe. Hypoplasia of the fovea, translucent iris, photophobia, nystagmus, decreased visual acuity, and inability of binocular vision are crucial to the diagnosis.

In addition to the features described, patients with oculocutaneous albinism have decreased pigmentation of skin and hair, whereas patients with ocular albinism have disease limited to the eyes. Albinism is not associated with impaired intelligence. In fact, an association with higher intellect may exist. Patients should be instructed to shield their eyes and skin from the sun.

There are no specific problems for most types of oculocutaneous albino patients undergoing surgery or anesthesia. However, patients with Chediak-Higashi Syndrome (Type VIB) or Hermansky-Pudlak Syndrome (Type VIA) have considerable anesthetic considerations. In general terms, all other types require routine preoperative evaluation. However, evaluation of coagulation parameters is recommended.

Provided that Hermansky-Pudlak syndrome and Chediak-Higashi syndrome could be excluded, there should be no specific anesthetic contraindications. Occasionally, patients complain of photophobia because of the brightness of the light in the operating room.

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