This type of oculocutaneous albinism is caused by mutations in the TYR gene (11q14-q21) and inherited in an autosomal recessive pattern.
Type IA (OCA1A) has no demonstrable tyrosinase activity while type IB (OCA1B, 606952) has a reduction in enzyme activity. Yet other patients with mutations in TYR have a variant called 'yellow albinism' in which tyrosinase activity resembles that found in type IB. To explain the difference in skin color, it has been suggested that an individual's background ethnicity may impact the pigmentation phenotype.
Other types also transmitted as autosomal recessive conditions are OCA2 (203200), OCA3 (203290), AND OCA4 (606574).