What symptom may occur in individuals with sickle cell trait?

Individuals with sickle cell trait can experience painless gross hematuria due to the sickling of red blood cells under certain conditions, particularly when they are dehydrated or at high altitudes. In sickle cell trait, individuals have a single copy of the hemoglobin S gene and typically lead normal lives without significant symptoms. However, in some cases, renal complications can arise, such as renal papillary necrosis, which can lead to blood in the urine. This hematuria is generally painless and can occur sporadically.

The other symptoms listed do not have a direct association with sickle cell trait. Painful abdominal cramps are often associated with sickle cell disease when vaso-occlusive crises occur due to sickled cells, but this is not characteristic of sickle cell trait. Frequent headaches and persistent dry cough may occur due to various other medical conditions but are not specifically linked to the pathology of sickle cell trait. Thus, painless gross hematuria is the most relevant symptom associated with individuals who have sickle cell trait.