Albinism

Prepared and reviewed by the PrepElephant Academic Review Team

First published 15 Oct 2026 · Spot an error?

Reference basis: Fitzpatrick's Dermatology; Rook's Textbook of Dermatology; Nelson Textbook of Pediatrics

On this page

Direct answer
What you must remember
Classifying albinism by molecular defect
Where the exam tries to catch you
Frequently asked questions
Related topics

Direct answer

Albinism is a group of inherited disorders of melanin synthesis that reduce pigment in the skin, hair and eyes. Oculocutaneous albinism is mostly autosomal recessive, and its types are separated by the gene involved and by whether tyrosinase activity is present. Affected people have a strongly increased risk of skin cancer, so lifelong sun protection and regular skin checks are essential.

What you must remember

OCA1: caused by tyrosinase (TYR) defects; OCA1A has no enzyme activity and gives white hair with pale blue eyes, while OCA1B retains some activity and hair darkens with age.
OCA2: caused by mutations in the P gene, giving yellow to light brown hair, and it is the commonest type worldwide.
OCA3: caused by TYRP1 mutations, with reddish-brown hair and skin, described in southern African populations.
OCA4: caused by SLC45A2 (MATP) mutations, with variable pigmentation.
Ocular albinism: X-linked (GPR143), with eye findings predominating and little change in skin colour.
Eye features: nystagmus, photophobia, reduced visual acuity, foveal hypoplasia and iris transillumination.
Hair bulb test: tyrosinase-positive types show melanin in the hair bulb after L-DOPA, while OCA1A does not.
Skin cancer: squamous and basal cell carcinomas are common and often appear early on sun-exposed skin.

Classifying albinism by molecular defect

Albinism is classified by the gene involved, and the clinical picture depends on residual tyrosinase activity. Each type carries a characteristic pattern of hair and eye pigmentation that helps guide counselling and investigation.

Type	Gene and defect	Hair and eye pattern
OCA1A	Tyrosinase (TYR), no enzyme activity	White hair, pale blue eyes, no darkening
OCA1B	TYR, residual activity	Hair darkens with age, eyes partly pigmented
OCA2	P gene, reduced melanin	Yellow to light brown hair, hazel eyes
OCA3	TYRP1	Reddish-brown hair and skin
OCA4	SLC45A2 (MATP)	Variable pigment, often reduced
Ocular albinism	GPR143, X-linked	Near-normal skin, eye features predominate

Tyrosinase status is assessed by the hair bulb test or by molecular analysis, and it predicts the likely course of hair darkening. In practice, a child with white hair, pale eyes and nystagmus should be tested for OCA1A and OCA2, since the hair bulb test and molecular analysis separate them.

The hair bulb test is a practical starting point where molecular testing is unavailable. Eye examination and skin cancer surveillance are needed in every type, because the absence of melanin removes natural protection from ultraviolet light.

Where the exam tries to catch you

Albinism questions test the classification, the eye findings and the cancer risk.

Trap: assuming that albinism has no eye involvement. Correct: nystagmus, photophobia and foveal hypoplasia occur across the oculocutaneous types and in ocular albinism.
Trap: believing that tyrosinase is the only gene involved. Correct: P protein and TYRP1 also cause albinism, so tyrosinase status alone does not explain every type.
Trap: reassuring the family that residual pigment makes skin cancer unlikely. Correct: the skin cancer risk remains high in all types, so lifelong photoprotection is required.

Frequently asked questions

What is the hair bulb test in albinism?

The hair bulb tyrosinase test incubates a plucked hair with L-DOPA, and melanin formation in the bulb indicates tyrosinase activity. The test is negative in OCA1A and helps classify oculocutaneous albinism when molecular testing is not available.

How does ocular albinism differ from oculocutaneous albinism?

Ocular albinism is X-linked and mainly affects the eyes, with little change in skin or hair colour. Oculocutaneous albinism is autosomal recessive and affects the skin, hair and eyes together. Both types can cause nystagmus and foveal hypoplasia.

Which skin cancers occur in albinism?

Squamous cell carcinoma and basal cell carcinoma are the commonest skin cancers in albinism, and they often appear early in life on sun-exposed skin. The absence of melanin removes natural ultraviolet protection, so lifelong photoprotection and regular skin examination are essential.

Which syndromes are associated with albinism?

Hermansky-Pudlak syndrome and Chediak-Higashi syndrome are the recognised syndromic forms of albinism. Hermansky-Pudlak syndrome causes a bleeding tendency and pulmonary fibrosis, whereas Chediak-Higashi syndrome causes recurrent infections and neutropenia.