Which side effect of statin medications like simvastatin should be the most concerning?

Choice A reason: While some patients might need short-term thyroid replacement therapy after radioactive iodine treatment, this is not as common as the need for long-term or lifelong therapy. Radioactive iodine often causes hypothyroidism, which requires ongoing thyroid hormone replacement.

Choice B reason: Radioactive iodine treatment frequently leads to hypothyroidism, where the thyroid gland no longer produces enough thyroid hormone. As a result, patients often require lifelong thyroid hormone replacement therapy to maintain normal thyroid function. This is a common outcome and patients should be prepared for this possibility when undergoing treatment for Graves' disease.

Choice C reason: Although radioactive iodine is effective in treating Graves' disease, it does not guarantee full recovery without the need for further treatment. Most patients will develop hypothyroidism and need thyroid hormone replacement therapy. Complete recovery without any need for ongoing management is uncommon.

Choice D reason: Lifelong iodine treatment is not required after radioactive iodine therapy for Graves' disease. The primary treatment involves administering a specific dose of radioactive iodine to ablate the overactive thyroid tissue. Following this, patients typically need thyroid hormone replacement therapy, not continuous iodine treatment.

Choice A reason: Autosomal-recessive disorders affect both males and females equally because the gene in question is located on one of the autosomes (non-sex chromosomes). Each individual has two copies of each autosomal gene, one from each parent. An autosomal-recessive disorder manifests when an individual inherits two copies of a mutant gene, one from each parent. Therefore, gender does not influence the likelihood of being affected.

Choice B reason: Autosomal-dominant disorders also affect both males and females equally. These disorders occur when a single copy of a mutant gene on an autosome is sufficient to cause the disorder. Since autosomes are present in both males and females equally, the likelihood of inheriting an autosomal-dominant disorder is not influenced by gender.

Choice C reason: Chromosomal nondisjunction refers to errors in cell division that result in an abnormal number of chromosomes. While some conditions resulting from chromosomal nondisjunction can show gender bias (such as Turner syndrome affecting females and Klinefelter syndrome affecting males), it is not accurate to say that males are generally more likely than females to be affected by chromosomal nondisjunction.

Choice D reason: X-linked (sex-linked) disorders are more likely to affect males than females because the gene causing the disorder is located on the X chromosome. Males have one X and one Y chromosome (XY), while females have two X chromosomes (XX). If a male inherits a mutant gene on the X chromosome, he will express the disorder because he does not have a second X chromosome to mask the effect. In contrast, females would need two copies of the mutant gene (one on each X chromosome) to express the disorder, making it less likely for them to be affected.