What is FOXP1 Syndrome?
FOXP1 syndrome is considered a rare disease that is caused by a mutation or change to the FOXP1 gene. The gene is located on chromosome 3 and includes the instructions or “recipe” for making the Forkhead BOXP1 protein. As a member of a family of transcription factors, it is vital in regulating the expression of other genes. FOXP1 controls when and how specific genes affect the development of the nervous system, along with many other systems. When a gene like FOXP1 does not function properly it can lead to a wide range of developmental delays and medical needs.
FOXP1 syndrome is characterized by delays in early motor and language milestones, mild-to-severe intellectual deficits, speech and language impairment in all individuals regardless of level of cognitive abilities, and behavior abnormalities (including autism spectrum disorder or autistic features, attention-deficit/hyperactivity disorder, anxiety, repetitive behaviors, sleep disturbances, and sensory symptoms). Other common findings are oromotor dysfunction (contributing to speech and feeding difficulties), refractive errors, strabismus, cardiac abnormalities, renal abnormalities, cryptorchidism, hypertonia, hearing loss, and epilepsy. To date, more than 200 individuals have been identified with FOXP1 syndrome.
As of the summer of 2023, the FOXP1 syndrome is now officially recognized and documented by the international medical community. Members of the FOXP1 Scientific Advisory Board submitted the required documentation that defined the specific conditions of the syndrome in a standardized format, covering diagnosis, management and genetic counselling for patients and their families. The submission went through a rigorous editing and peer review process before it was published online. As a result the FOXP1 syndrome is now published in several online medical libraries, and should be referenced by all clinicians, support workers, and family members who work with persons with FOXP1 syndrome.
The International FOXP1 Foundation and community would like to extend a sincere Thank-you to the SAB members and researchers who contributed to the writing, editing, and peer review of the FOXP1 syndrome submission. Without your efforts, our local family doctors and practitioners would not have a better understanding of our children's condition.
Dr. Gudrun Rappold, Dr. Paige Siper, Dr. Ana Kostic, Dr. Ruth Braden, Dr. Angela Morgan, Dr. Saskia Koene, and Dr. Alex Kolevzon.
What causes FOXP1 Syndrome?
Chromosomes are the structures that carry an individual’s genetic information. This information is encoded by units called genes, which can be thought of as long words made up of strings of 4 different “letters” (A, G, T, and C). Genes are arranged along the chromosome like words in a sentence. In humans, each cell normally contains 23 pairs of chromosomes, for a total of 46 chromosomes. Twenty-two of these pairs (autosomes) look the same in males and females. The 23rd pair (sex chromosomes) differs between sexes. Humans usually have two copies of every gene on the autosomes, including FOXP1.
FOXP1 syndrome is caused by genetic lesions (mutations) of the FOXP1 gene. These include a swap of a single letter or loss or gain of a few letters on one copy of the gene, as well partial or total deletions of one copy of the gene. The disorder is referred to as "autosomal dominant" because mutations of a single copy of FOXP1 are enough for a person to be affected. FOXP1 mutations typically arise spontaneously in affected individuals (that is, not inherited), and are therefore referred to as “de novo” mutations. Because the parents would typically have two
normal copies of the FOXP1 gene, there is a very small chance to have a second
child with FOXP1 syndrome.
How common are FOXP1 gene mutations?
FOXP1 mutations are rare, but more and more cases are being identified as genetic testing becomes more widespread. There are several online parent groups that operate in difference languages on Facebook. Each year dozens of new cases are indentured around the globe. There are likely many more people carrying mutations in the gene who have not yet been diagnosed.