Which of the following is caused by an abnormality in melanin production?

The correct answer reflects conditions that arise from abnormalities in melanin production. Both leukoderma and albinism are characterized by variations in melanin levels, leading to changes in skin pigmentation.

Leukoderma refers to localized areas of skin that have lost their pigmentation, resulting in white patches. This condition can occur due to various factors, such as autoimmune disorders or chemical exposure, which affect the melanocytes—the cells responsible for producing melanin.

Albinism, on the other hand, is a genetic condition where there is a complete or partial absence of melanin in the skin, hair, and eyes. This occurs due to mutations in the genes responsible for melanin production, leading to a significantly reduced ability to form this pigment.

Both of these conditions highlight the effects of melanin abnormalities: leukoderma shows localized loss, while albinism demonstrates a systemic lack of melanin. In contrast, psoriasis is primarily an inflammatory skin condition that does not involve a direct issue with melanin production, hence it is not relevant to this question about pigment abnormalities.