Which of the following conditions is NOT included in a diagnosis of Other Health Impairments (OHI)?

In the context of the Individuals with Disabilities Education Act (IDEA), Other Health Impairments (OHI) refers to a range of health issues that can adversely affect a child's educational performance. Conditions typically included under OHI encompass those that limit strength, vitality, or alertness and can include chronic or acute health problems.

Multiple sclerosis is a serious condition affecting the central nervous system and can lead to various disabilities. However, it is usually categorized under a different eligibility category related to specific disabilities rather than OHI. The other options, including sickle cell anemia, nephritis, and heart conditions, are often classified under Other Health Impairments due to their potential to severely affect a child's health and ability to learn.

Thus, multiple sclerosis stands apart from more commonly classified conditions under OHI, making it the correct answer to be excluded from this diagnosis.