The TYR gene (MIM #6069333) is located at position 11q14.3 on the human 
chromosome, and encodes tyrosinase, which is expressed in melanocytes and 
controls the biosynthesis of melanin. Most TYR mutations eliminate the activity 
of tyrosinase, preventing melanocytes from producing any melanin throughout 
life. People with this form of albinism have white hair, light-coloured eyes and 
very pale skin. Some mutations in TYR reduce but do not completely eliminate 
tyrosinase activity, and allow some melanin to be produced. We report a 
Pakistani family with four members affected by oculocutaneous albinism (OCA). 
Blood samples were collected from all affected individuals, normal siblings and 
their parents. Genomic DNA was extracted, and sequence analysis of all the 
coding exons and adjacent intronic sequences of TYR was performed, which 
identified a novel missense substitution (p.Ile198Thr). Sequencing of TYR in 90 
unrelated healthy individuals showed no sequence variant at this location. Our 
study expands the mutational spectrum of OCA1.