**Core Concept**
G-6-PD deficiency is a genetic disorder affecting the enzyme glucose-6-phosphate dehydrogenase, which protects red blood cells from oxidative damage. This condition exhibits an X-linked recessive pattern of inheritance, where the mutated gene responsible for the disease is located on the X chromosome. Females are typically carriers of the mutated gene, while males are more likely to express the condition due to their single X chromosome.

**Why the Correct Answer is Right**
G-6-PD deficiency is caused by mutations in the G6PD gene, which is located on the X chromosome. In females, one normal X chromosome compensates for the presence of the mutated gene, so they usually remain asymptomatic or have mild symptoms. In males, who have only one X chromosome, the mutated gene leads to a complete deficiency of the enzyme, resulting in hemolysis (red blood cell destruction) upon exposure to oxidative stressors. This X-linked recessive pattern of inheritance makes G-6-PD deficiency a significant concern in populations with a high prevalence of the mutation.

**Why Each Wrong Option is Incorrect**
**Option B:** Neurofibromatosis is an autosomal dominant condition, characterized by the development of multiple neurofibromas and café-au-lait spots. It is not linked to the X chromosome and does not exhibit an X-linked recessive pattern of inheritance.
**Option C:** Thalassemia is an autosomal recessive disorder affecting the production of hemoglobin, leading to anemia and other complications. While it is a genetic disorder, it is not X-linked recessive.
**Option D:** Alkaptonuria is an autosomal recessive condition caused by a deficiency of homogentisate 1,2-dioxygenase, leading to the accumulation of homogentisic acid in the body. It is not linked to the X chromosome and does not exhibit an X-linked recessive pattern of inheritance.

**Clinical Pearl / High-Yield Fact**
When evaluating a patient with hemolytic anemia, it is essential to consider G-6-PD deficiency, particularly in populations with a high prevalence of the mutation. A key clinical clue is the presence of hemolysis triggered by exposure to certain medications, such as antimalarial drugs, or specific foods, such as fava beans.

**✓ Correct Answer: A. G-6-PD deficiency**