Welcome to FOXG1 UK

FOXG1 Syndrome

FOXG1 Syndrome is a rare neuro-developmental condition associated with mutations in the forkhead box G1 (FOXG1) gene. A de novo pathogenic variant in FOXG1 was first discovered via fluorescence in situ hybridization and southern blot hybridization in a girl with severe cognitive disability associated with complete agenesis of the corpus callosum and microcephaly in 2005. The FOXG1 gene provides instructions for making a protein known as forkhead box G1. This protein is a transcription factor, which means it helps regulate the activity of other genes. This protein plays an important role in brain development, particularly in a region of the embryonic brain known as the telencephalon. The telencephalon ultimately develops into several critical structures, including the the largest part of the brain (the cerebrum), which controls most voluntary activity, language, sensory perception, learning, and memory.

Typical Symptoms

There is a wide variation in both the symptoms and severity experience by patients with FOXG1 Syndrome.



FOXG1 is diagnosed through genetic testing in individuals suspected of having the syndrome. A medical genetic test is most often carried out by taking a blood sample from the patient’s arm. The genetic material is extracted from blood cells in the laboratory and used in the testing process.

Parents will often undergo a Carrier Test to see if they have passed the syndrome on to the child. In the majority of cases of FOXG1 Syndrome the genetic mutation was de novo which means the parents did not carry the mutation.Geneticists will meet with families to discuss the diagnosis and explain exactly what type of mutation the patient has.

Types of Genetic Mutation