FOXG1 Syndrome

Excerpt

Clinical characteristics: FOXG1 syndrome is characterized by moderate-to-profound developmental delay and intellectual disability, postnatal growth deficiency, congenital or postnatal microcephaly, hyperkinetic/dyskinetic movement disorder, hypotonia, neurobehavioral/psychiatric manifestations (motor stereotypies, impairment of social interaction, abnormal sleep patterns, unexplained episodes of crying, restlessness, and bruxism), feeding difficulties with poor weight gain, strabismus, seizures, spasticity, gastroesophageal reflux, and aspiration. Some individuals have cortical visual impairment, kyphosis, scoliosis, and/or abnormal breathing. Characteristic neuroimaging findings include corpus callosum anomalies (especially a marked, filiform thinning of the rostrum of the corpus callosum), a simplified gyral pattern, and hyperplasia of the fornices.

Diagnosis: The diagnosis of FOXG1 syndrome is established in a proband with clinical and/or characteristic neuroimaging findings and a heterozygous pathogenic variant in FOXG1 identified by molecular genetic testing.

Management: Treatment of manifestations: Developmental and educational support; consideration of anti-dyskinetic pharmacotherapy; treatment for seizures by an experienced neurologist; treatment of spasticity per orthopedist; physical medicine and rehabilitation, physical therapy, and occupational therapy to help avoid contractures and falls; anti-spasmodic pharmacotherapy; feeding therapy with gastrostomy tube placement as needed; standard treatment of gastroesophageal reflux; treatment for refractive errors and strabismus per ophthalmologist; standard treatments for scoliosis; social work and family support.

Surveillance: At each visit, monitor developmental progress, educational needs, seizures, changes in tone, movement disorders, growth, nutritional status, and safety of oral intake; behavioral assessment for irritability and sleep issues; assess for evidence of gastroesophageal reflux, aspiration, and/or respiratory insufficiency; physical medicine, occupational therapy, physical therapy assessment for mobility and self-help skills; monitor for strabismus and need for low vision services per treating ophthalmologist; assess family needs.

Genetic counseling: FOXG1 syndrome is an autosomal dominant disorder typically caused by a de novo pathogenic variant. Risk to future pregnancies is presumed to be low as the proband most likely has a de novo FOXG1 pathogenic variant. There is, however, a recurrence risk to sibs based on the possibility of parental germline mosaicism. Given this risk, prenatal and preimplantation genetic testing may be considered.