Key clinical characteristics include of FOXG1 syndrome include:
• Developmental Delay and Intellectual Disability
o Most individuals experience what is known as Global Developmental Delay, which is essentially when a child experiences delay in reaching important developmental milestones in two or more areas, including walking, talking, understanding language, etc. Cognitive and motor functions are underdeveloped in the majority of patients.
• Microcephaly and Brain Abnormalities
o Postnatal microcephaly, which is when a child’s head fails to grow at normal rates after birth, is a major hallmark. Many children also have brain malformations visible through MRI scans in the frontal regions. The folds in the brain are simpler than typical, certain regions experiencing thinning, etc.
• Movement Disorders (Hyperkinetic)
o Movements occurring uncontrollably in excess are another core feature. Intermittent jerking movements and hand flapping are observed as well. Muscle tone can be reduced in early childhood, but potentially become more rigid as the individual grows older.
• Epilepsy
o Epileptic seizures occur in approximately 60–80% of diagnosed individuals. It most often begins occurring in infancy.
• Behavioral and Sensory Features
o Irritability and an unsettled demeanor are frequently noted in infancy. Many children demonstrate features associated with autism, such as poor eye contact, lack of social interactions and repetitive behaviors. Nearly all diagnosed individuals lack verbal speech. Additionally, visual impairment due to changes in brain processing is common, and affected infants may be less responsive to their visual environment despite having intact eyes. Other findings can include feeding difficulties, and collectively, these features can lead to a poorer quality of life.
FOXG1