SNP Shot: Genomic Insights

Oculocutaneous albinism (OCA) encompasses a range of genetic disorders impacting the pigmentation (coloring) of skin, hair, and eyes. Individuals with OCA generally present with very light skin and hair that is white or a light shade. Due to reduced pigment, they are highly susceptible to sun damage and a greater risk of developing skin cancers, including melanoma, a particularly dangerous type. OCA also affects the iris (colored part of the eye) and retina (light-sensitive tissue at the back of the eye), leading to various vision impairments. Common vision problems include decreased visual acuity, involuntary, rapid eye movements (nystagmus), and heightened sensitivity to light (photophobia).

Scientists have identified several distinct types of OCA, each characterized by specific variations in skin, hair, and eye pigmentation, as well as unique genetic origins. OCA type 1 typically involves white hair, extremely pale skin, and light-colored irises. OCA type 2 is generally less severe than type 1, with creamy white skin and hair that may be light yellow, blonde, or light brown. OCA type 3 includes rufous OCA, predominantly affecting individuals with darker skin. Those with rufous OCA typically have reddish-brown skin, ginger or red hair, and hazel or brown irises. Vision problems associated with type 3 are often less pronounced than those seen in other OCA types. The symptoms and signs of OCA type 4 are similar to those of type 2.

In addition to the primary types, several rarer forms of OCA have been identified, each affecting a limited number of families.

Inheritance:

OCA follows an autosomal recessive inheritance pattern. This means that an individual must inherit a variant (mutation) in both copies of the responsible gene in each cell to develop the condition. Typically, the parents of an individual with an autosomal recessive condition each carry one copy of the altered gene, but they do not exhibit any signs or symptoms of the disorder.