Trial 21

Identifying the risk factors for the onset of Alzheimer’s disease in adults with trisomy 21

Project Progress

Monitoring in progress

In collaboration with:

Hôpital Lariboisière
Groupe Hospitalier Paris Saint-Joseph
Hôpital Pitié-Salpêtrière


To identify the risk factors influencing the onset of Alzheimer’s disease in patients with trisomy 21 aged at least 35 years old. This information will help improve our knowledge of the disease’s mechanisms.

The secondary objectives are:

  • To monitor cognitive functions (memory, language, reasoning)
  • To identify markers for Alzheimer’s disease (in the blood, in the cerebrospinal fluid, using MRI)
  • To assess how well patients tolerate the medical examinations

Study Population

For the purposes of the study, 200 patients with trisomy 21 aged at least 35 years old and without diagnosed Alzheimer’s disease will be enrolled and monitored at the Jérôme Lejeune Institute.

How the Study is Being Conducted

The TRIAL 21 study started in March 2019 and will run for at least 4 years. Each patient’s participation in the study will last 24 months. An annual routine follow-up visit will then be offered as part of their usual management. This will be offered for 10 years from the final visit in the study, the objective being to collect data relating to the potential onset of Alzheimer’s disease.



People with trisomy 21 have a higher risk of developing Alzheimer’s disease.

Why? Because the β-amyloid protein that accumulates in the brain of people with Alzheimer’s disease is produced by the APP gene on chromosome 21. People with trisomy 21 have an additional chromosome 21: since the APP gene is overexpressed, they therefore produce excess β-amyloid protein.

Everyone with trisomy 21 is affected by these biological events since it is a genetic predisposition. There is nevertheless a great variation in these patients’ age at the onset of symptoms, ranging from 40 to over 70 years old. This suggests that genetic, biological and environmental factors may contribute to aggravating or slowing down the disease’s progression.

Early changes linked to Alzheimer’s disease are especially difficult to detect in adults with trisomy 21 due to their intellectual disability. It is therefore essential to identify the factors involved in the disease’s progression to enable early diagnosis and to develop effective treatments, for people with trisomy 21 and for everyone affected by the disease.