BACKGROUND: Oculocutaneous albinism (OCA) is an autosomal recessive disorder of 
abnormal melanin formation, which results in hypopigmentation of skin, hair and 
eyes. OCA is classified into four types based on clinical and genetic findings. 
OCA1 is the most severe form of albinism, and is caused by mutations in the 
tyrosinase (TYR) gene, while OCA4 is caused due to mutations in SLC45A2.
METHODS: In total, 13 families with ≥ 3 members with OCA were enrolled. Family 
history was ascertained and pedigrees were drawn up. Blood samples were 
collected and processed for DNA extraction. Linkage analysis was performed by 
typing three short tandem repeat markers in candidate regions of TYR and 
SLC45A2. Sequence analysis was performed of all the coding exons and adjacent 
intronic sequences of both genes.
RESULTS: Eight families showed linkage to OCA1 and one family showed linkage to 
OCA4. Four missense substitutions (p.Arg239Trp, p.Ser192Tyr, p.Ser44Arg and 
p.Arg77Gln) were identified in TYR in the families with OCA1 linkage, and 
another missense substitution (p.Gln272Lys) was identified in the family with 
OCA4 linkage. One of the identified missense substitution (p.Arg77Gln) in TYR 
was found in five different families, which had a common haplotype.
CONCLUSIONS: We identified four missense substitutions in TYR and a single 
missense substitution in SLC45A2. One missense substitution (p.Arg77Gln) in TYR 
was found in five different families that originated from the same geographical 
area and displayed a common haplotype, suggesting a single origin that then 
spread to different geographical areas of Azad Kashmir, Pakistan.