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G6PD (Glucose-6-Phosphate Dehydrogenase) deficiency is an X-linked recessive condition, meaning that the gene mutation responsible for the deficiency is located on the X chromosome. Since males have only one X chromosome (hemizygous), they are more likely to express X-linked conditions when they inherit the affected gene. In contrast, females have two X chromosomes (homozygous; one normal and one affected) and can be carriers of the condition without showing symptoms if they inherit one normal X chromosome from one parent.

In this context, hemizygous males will manifest the condition due to their single X chromosome being affected. Homozygous females, which means that both X chromosomes are affected, can also exhibit the condition, but this is less common since females have a lower probability (compared to males) of being homozygous for the mutation.

Therefore, the group that predominantly exhibits G6PD deficiency is hemizygous males and, to a lesser extent, homozygous females. This leads to the conclusion that hemizygous males predominantly show the condition, while homozygous females can also express the deficiency, even if less frequently than males.