Alzheimer Disease, Type 4

What is Alzheimer disease, type 4?

Alzheimer disease, type 4 is an early-onset, familial form of Alzheimer disease. It is similar to other forms of early onset Alzheimer disease, but each type is caused by mutations in a different gene. This degenerative disease of the brain causes gradual loss of memory, judgment, and ability to function.

Alzheimer disease, type 4 is a subtype of Alzheimer disease.

As in the other types of Alzheimer disease, the most common sign of type 4 Alzheimer disease is memory loss. The disorder usually develops between ages 40 and 75. The course of the disease averages 11 years, and death most often results from pneumonia, malnutrition, or general body wasting. For additional information about the signs and symptoms of this disorder, please refer to the Alzheimer disease summary.

How common is Alzheimer disease, type 4?

Early-onset familial Alzheimer disease accounts for fewer than 2 percent of all cases of Alzheimer disease. Alzheimer disease, type 4 has been identified in only a few families worldwide. It accounts for fewer than 5 percent of all cases of early-onset, familial Alzheimer disease.

What genes are related to Alzheimer disease, type 4?

Mutations in the PSEN2 gene cause Alzheimer disease, type 4.

The PSEN2 gene produces a protein called presenilin 2. Mutations in the PSEN2 gene alter the structure and function of this protein, which leads to the increased production of a protein fragment called amyloid beta peptide, a substance found in the brain and other tissues. This peptide can build up in the brain to form clumps called amyloid plaques, which are characteristic of Alzheimer disease and lead to the signs and symptoms of the disorder.

How do people inherit Alzheimer disease, type 4?

This condition is inherited in an autosomal dominant pattern, which means one copy of the altered gene in each cell is sufficient to cause the disorder.

In most cases, an affected person has one parent with the condition.

What other names do people use for Alzheimer disease, type 4?

  • AD4
  • Alzheimer disease, familial, type 4
  • Alzheimer Disease Type 4 (AD4)

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