What is the recurrence risk for early-onset Alzheimer's disease with one affected sibling?

The recurrence risk for early-onset Alzheimer's disease, particularly when considering a family history that includes one affected sibling, is generally estimated to be in the range of 4-12%. This risk is influenced by the genetic components associated with early-onset Alzheimer's, which typically has a strong familial linkage due to mutations in specific genes such as APP, PSEN1, and PSEN2.

When a sibling is affected, there’s a notable increase in the likelihood that other family members may also develop the condition because the genetic predisposition is shared among siblings. Although this number can be influenced by other factors such as environmental interactions and the specific family pedigree, the established statistics put the risk after one sibling is diagnosed within that range.

The other options, which provide smaller percentages, do not align with the current understanding of the genetics of early-onset Alzheimer's disease in the context of familial recurrence risks. These lower values underestimate the potential genetic contribution and the prevalence of mutations that can lead to early onset when there is a direct familial connection.