Alzheimer Disease, Type 3

What is Alzheimer disease, type 3?

Alzheimer disease, type 3 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 3 is a subtype of Alzheimer disease.

As in the other types of Alzheimer disease, the most common sign of type 3 Alzheimer disease is memory loss. This type of Alzheimer disease develops during midlife, almost always before age 65. Signs and symptoms usually appear in the forties or early fifties, but can start as early as the thirties. The disease progresses rapidly, with a course of 6 to 7 years. For additional information about the features of this disorder, please refer to the Alzheimer disease summary.

How common is Alzheimer disease, type 3?

Fewer than 2 percent of all cases of Alzheimer disease are the early-onset, familial form of the disorder. Type 3 Alzheimer disease affects 30 to 70 percent of all families with early-onset, familial Alzheimer disease.

What genes are related to Alzheimer disease, type 3?

Mutations in the PSEN1 gene cause Alzheimer disease, type 3.

The PSEN1 gene produces a protein called presenilin 1. Mutations in the PSEN1 gene alter the structure and function of this protein, which results in 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 3?

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 3?

  • AD3
  • Alzheimer disease, familial, type 3
  • Alzheimer Disease Type 3 (AD3)

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