Certified Pediatric Hematology Oncology Nurse (CPHON) Practice Exam 2026 - Free CPHON Practice Questions and Study Guide

The genetic basis of Glucose 6 Phosphate Dehydrogenase (G6PD) deficiency is primarily linked to its location on the X chromosome, specifically at band Xq28. This means that the disorder is inherited in an X-linked recessive pattern, affecting males more significantly than females. Males who inherit one mutated X chromosome will express the deficiency since they possess only one X chromosome. Females, having two X chromosomes, may be carriers if they have one affected X chromosome but can also be affected if both X chromosomes carry the mutation.

This inheritance pattern is important in understanding the prevalence and presentations of the deficiency. For example, G6PD deficiency is more common in individuals of specific ethnic backgrounds, such as those from parts of Africa, the Mediterranean region, and Asia, due to the selective advantage it confers against malaria.

Options that suggest autosomal inheritance, codominant traits, or polygenic inheritance do not align with the established understanding of G6PD deficiency, as the trait's expression and transmission specifically follow the X-linked recessive pattern. Thus, the correct identification of the genetic basis reinforces the significance of X-linked inheritance in this condition.