What characterizes McCune-Albright syndrome?

McCune-Albright syndrome is characterized primarily by the presence of cafe au lait spots, which are flat, hyperpigmented skin lesions resembling coffee with milk. These spots are often seen in a pattern that may be irregular or have jagged borders, which distinguishes them from other benign pigmented lesions.

In addition to cafe au lait spots, individuals with McCune-Albright syndrome may also experience other features such as bone changes (including fibrous dysplasia) and endocrine abnormalities, but the cafe au lait spots are one of the hallmark signs used to identify this condition.

The other choices listed, while relevant in other contexts, do not specifically characterize McCune-Albright syndrome. Thrombocytopenia (a condition characterized by low platelet counts) and severe intellectual disability are associated with various other genetic conditions but are not characteristic of McCune-Albright syndrome. Thickened skin is not a feature of this syndrome either; rather, skin changes associated with McCune-Albright syndrome are primarily about the presence of cafe au lait spots without significant thickening. Thus, the defining characteristic of McCune-Albright syndrome is the presence of these specific skin lesions.