Cutaneous depigmentation is not apparent. CHS presents with complete to moderate absence of pigment in the skin, hair and eyes. The hypopigmentation of the hair in CHS generally has a distinct silvery, metallic sheen. Respiratory infections frequently occur shortly after birth. HPS presents with a variable amount of depigmentation in the skin, hair and eyes.
Ophthalmic findings are also variable.
Type 1 results from mutations in the tyrosinase gene, which maps to human chromosome 11q14-2 and is inherited as an autosomal recessive trait. The tyrosinase gene encodes an enzyme that initiates the synthesis of melanin using the substrate tyrosine. There have been more that 70 mutations identified in tyrosinase that result in the dysfunction or lack of synthesis of this enzyme. Most OCA1 patients are compound heterozygotes for mutations in the tyrosinase gene. Type 2 results from mutation in the P gene, which maps to human chromosome 15q11-13 and is inherited as an autosomal recessive trait.