According to experts, genes linked to an increased risk of Alzheimer's disease could really represent an inherited form of the illness.

 A recent study published in the journal Nature Medicine suggests that Alzheimer’s disease may have a stronger genetic component than previously believed, shedding new light on a gene long associated with this form of dementia.

Traditionally, Alzheimer's has been categorized into familial and sporadic forms. Familial cases, resulting from mutations in specific genes, are rare and tend to manifest earlier in life, while sporadic cases, thought to develop later, are more common. However, this new study challenges this distinction, proposing that a significant portion of Alzheimer's cases could be hereditary, particularly linked to a gene responsible for producing a protein called apolipoprotein E (APOE).

The study underscores the role of the APOE gene in Alzheimer's risk. While one variant, APOE2, may offer protection, another variant, APOE4, significantly increases the risk of developing the disease. Individuals carrying two copies of the APOE4 gene are particularly vulnerable, with nearly all showing signs of Alzheimer's pathology by their early 80s.

Moreover, the study suggests that having two copies of the APOE4 gene may not only elevate the risk but also hasten the onset of Alzheimer's symptoms, typically occurring around the age of 65. This genetic predisposition mirrors the progression observed in other hereditary forms of the disease, emphasizing the significance of APOE4 in Alzheimer's pathology.

However, the study also highlights variability in how APOE4 manifests. While it reliably triggers Alzheimer's pathology in most cases, some individuals with this genetic profile may remain asymptomatic due to other genetic or environmental factors. Nevertheless, when symptoms do emerge, they tend to appear earlier and progress more rapidly than in other forms of Alzheimer's.

These findings have profound implications for understanding the genetic basis of Alzheimer's and may prompt a reevaluation of diagnostic and treatment approaches. While current guidelines do not recommend routine APOE testing for diagnosis, the study suggests that such testing could be beneficial, particularly for individuals considering amyloid-clearing medications. Furthermore, recognizing the significance of APOE4 in Alzheimer's risk may prompt tailored treatment strategies and earlier interventions for those at heightened genetic risk.