1q21.1 Duplication

Learn more about 1q21.1 Duplication and connect with other Simons Searchlight families with the resources below.

What does it mean to have a 1q21.1 duplication?

Genes provide our body with instructions. Our body carries genes in structures called chromosomes. We have two copies of each chromosome, one from the birth father and one from the birth mother. Sometimes people are born with extra or missing sections of chromosomes. Extra or missing genetic material can impact health, learning, and behavior. The effects vary based on the location and size of the changes and what the genes there do.

People with 1q21.1 duplications have a specific extra section in one of their two copies of chromosome 1.

People with 1q21.1 duplications appear to have an increased risk for development problems, including autism. Depending on what genetic information is missing, the lack of it can impact a person’s health, learning, and behavior. What scientists know about 1q21.1 duplications is limited, and families and doctors share a critical need for more information.


Genetic Information

What genes are involved in typical (Class 1) 1q21.1 deletions and duplications?

In the “typical” 1q21.1 deletion or duplication, there are about 20 genes that are missing (deleted) or extra (duplicated). Some have not been researched at all, and have been left out of the summary.

These genes that begin with “NBPF” have been found in children with features like macrocephaly, autism, schizophrenia, intellectual disability, congenital heart disease, neuroblastoma, and problems with the kidney and urinary tract. This gene family contains many pseudogenes (see definition below).

  • PRKAB2 – Important for regulating energy in cells (involved in making fatty acids and cholesterol for cells)
  • FMO5 – Two missing copies of this gene are associated with a condition called “Trimethylaminuria,” which causes an unusual odor.
  • GJA8 – Important for the growth of specific cells in the eye called “lens fiber cells.” Missing copies of this gene (deletions) can result in an increased chance for cataracts.
  • CHD1L – Important in chromatin remodeling (this is like “behind-the-scenes” work with preparing DNA to be used, read, or copied).
  • BCL9 – The function of this gene is unknown when it is deleted or duplicated in a person. Errors in this gene have been found in patients with B-cell acute lymphoblastic leukemia. The errors with this gene are thought to happen in a person’s cancer cells (which are usually genetically different than the cells in the rest of a person’s body. We do not think that people who have deletions or duplications of this gene are at an increased risk for leukemia.


What is a pseudogene?

Pseudogenes are thought to be inactive gene. (“Pseudo” means “fake” in Latin.) They are similar to normal genes, but are not functional. The information or “genetic sequence” of a pseudogene is often similar to another gene that has a job in the body. Pseudogenes arise because of copying errors that have happened in the past. They are actually copies of other functioning genes, that were incorporated into a person’s DNA a very long time ago, but no longer have a job. Pseudogenes are considered “non-coding” DNA.



1q21.1 Duplication disorder is listed in this GeneReviews under a genetically related disorder.



Fact Sheet

Download a copy of our 1q21.1 Duplication Fact Sheet here.


Research Article Summaries

Below, we have summarized research articles about 1q21.1 Duplications. We hope you find this information helpful.

The information available about 1q21.1 Duplications is limited, and families and doctors share a critical need for more information. As we learn more from children who have a change in this gene, we expect this list of resources and information to grow.


Clinical phenotype of the recurrent 1q21.1 copy-number variant

Original research article by Bernier R. et al. (2016).

Read the article here and the Simons Searchlight summary here.

Read news coverage of the article here.


Research Opportunities

Simons Searchlight

Help the Simons Searchlight team learn more about 1q21.1 Duplications by taking part in our research. You can learn more about the project and sign up here.


Facebook Group

Connect with other families in our Facebook Group.

Join the group by clicking here.


Family Stories

Stories from 1q21.1 Duplication families:

Click here to share your family’s story.