Albinism

Albinism is a genetic disorder that causes a deficiency in melanin, the pigment responsible for the color of the skin, hair, and eyes in humans.

People with albinism often have pale or very light skin, as well as light hair.

Albinism occurs in all racial and ethnic groups worldwide. Most children with albinism are born to parents with normal hair and eye color.

Approximately 1 in 70 people is a carrier of the albinism gene.

People with albinism often have vision problems and an increased risk of developing skin cancer.

Melanin usually protects the skin from damage caused by exposure to ultraviolet radiation, making individuals with albinism more sensitive to sunlight. It is crucial for individuals with albinism to protect their skin and eyes from the sun.

Causes of Albinism

Albinism is caused by mutations in certain genes responsible for melanin production. Melanin is produced by cells called melanocytes, which are found in the skin, hair, and eyes. Due to the damage to these genes, melanin may either not be produced at all or produced in smaller amounts.

In most cases, people with albinism inherit the faulty genes from both mother and father. The parents may not show signs of albinism but can be carriers of the genes.

Depending on which genes are affected, albinism can be divided into several types.

Types of Albinism

There are two main types of albinism:

• Oculocutaneous albinism (OCA) - the most common type, affecting the skin, hair, and eyes.
• Ocular albinism (OA), which only affects the eyes.

Genetics and Albinism

All types of oculocutaneous albinism and some types of ocular albinism are inherited in an autosomal recessive pattern.

Autosomal Recessive Inheritance

Children inherit one copy of each gene from their mother and father. In autosomal recessive inheritance, the disease or trait manifests if two copies of a faulty gene are inherited.

If both parents are carriers of the faulty gene, they usually do not exhibit albinism. Each can pass on to their child either a normal gene or a damaged one.

The likelihood of a child inheriting albinism from parents who are carriers of the mutated gene is as follows:

• 25% - the child will inherit two normal genes and will be completely healthy.
• 50% - the child will inherit one normal gene and one faulty gene, becoming a carrier without signs of albinism.
• 25% - the child will inherit two faulty genes and will have albinism.

X-Linked Inheritance

Most types of ocular albinism are transmitted through X-linked inheritance.

X-linked inheritance is a way of passing certain characteristics from parents to children through the X chromosome.

The 23rd pair of chromosomes is called the sex chromosomes and differs between men and women. Women usually have two X chromosomes (XX). One X chromosome is inherited from the mother and one X chromosome from the father. Men typically have one X chromosome and one Y chromosome (XY). The X chromosome is inherited from the mother and the Y chromosome from the father.

If the mother is a carrier of the X-linked type of albinism, she has one normal X chromosome and one damaged one. She passes one of her X chromosomes to her daughter, making her a carrier in 50% of cases. Sons (who have only one X chromosome) have a 50% chance of getting albinism, as the presence of one copy of the faulty gene will be enough.

If the father is a carrier of the X-linked type of albinism, then his daughters will be carriers, while his sons will not have albinism and will not be carriers.

Men suffer from X-linked recessive disorders much more often than women because the likelihood that a woman will have both copies of the faulty gene is lower.

Treatment

Albinism is an incurable genetic disorder. People with albinism need proper eye care and must diligently monitor their skin for any changes, using sunscreen to protect themselves from the sun.