Hi!
What is albinism?
Albinism is a genetic disorder that results in the skin, hair and eyes to have close to no color. This is heritable, and in the lack of color in the aforementioned parts is due to decreases levels of melanin in the body. Melanin is a pigment that imparts the characteristic colors to the skin, hair and eyes, and is produced by melanocytes -more the melanin, more the color (darker).
How can someone have albinism?
In albinism, there is a defect (mutation) in the gene responsible for the production of melanin, which is tyrosinase. Even if one of the allele for the gene tyrosinase is defective, the other functional allele can ensure enough melanin production to impart color. So for a person to have albinism, he or she must have two defective alleles for tyrosinase. A person acquires one allele from the mother, and one from the father, so a person will have a chance of having albinism if his/her parents both have at least one defective allele of tyrosinase.
Hope this helps!