Clinical Guidance

Several reports have indicated a genotype-phenotype association. Individuals with truncating pathogenic variants or intragenic deletions show more severe clinical phenotypes than those with missense pathogenic variants . The most severe clinical phenotypes were observed in individuals with a frameshift or nonsense pathogenic variant in the N-terminal domain and the forkhead domain, except conserved site 1. In contrast, milder phenotypes were associated with missense pathogenic variants in the forkhead conserved site 1 . Simplified gyral pattern occurred significantly more frequently in individuals with pathogenic frameshift and nonsense variants in the N-terminal domain . For most of the neuroimaging anomalies, no genotype-phenotype correlations were discernible .

Source: GeneReviews — "FOXG1 Syndrome"

Penetrance

To date, no individuals (e.g., parent) with a pathogenic variant have been reported to be non-penetrant. Thus, penetrance is expected to be complete.

Source: GeneReviews — "FOXG1 Syndrome"

Diagnostic Criteria

Suggestive Findings

FOXG1 syndrome should be considered in probands with the following clinical and brain MRI findings.

Clinical findings

Source: GeneReviews — "FOXG1 Syndrome"

Differential Diagnosis

Table 3. Selected Disorders of Interest in the Differential Diagnosis of FOXG1 Syndrome

Management Guidelines

No clinical practice guidelines for FOXG1 syndrome have been published.

Evaluations Following Initial Diagnosis

To establish the extent of disease and needs in an individual diagnosed with FOXG1 syndrome, the evaluations summarized (if not performed as part of the evaluation that led to diagnosis) are recommended.

Table 4.

FOXG1 Syndrome: Recommended Evaluations Following Initial Diagnosis

System/Concern | Evaluation | Comment

Development

| Developmental assessment | • To incl motor, adaptive, cognitive, speech-language eval

• Eval for early intervention/ special education

Neurologic

| Neurologic eval | • To incl brain MRI

• Consider EEG if seizures are a concern.

• To incl eval for hyperkinetic/dyskinetic movement disorder

Neurobehavioral

| Neuropsychiatric eval | • For infants: screening for irritability, episodes of crying, abnormal sleep patterns

• For persons age 12 mos: screening for concerns incl sleep disturbances, impairment of social interaction

Therapies Under Investigation

Search ClinicalTrials.gov in the US and EU Clinical Trials Register in Europe for access to information on clinical studies for a wide range of diseases and conditions. Note: There may not be clinical trials for this disorder.

Source: GeneReviews — "FOXG1 Syndrome"

Surveillance Guidelines

To monitor existing manifestations, the individual's response to supportive care, and the emergence of new manifestations, the evaluations summarized in are recommended.

Table 6.

FOXG1 Syndrome: Recommended Surveillance

System/Concern | Evaluation | Frequency

Development

| Monitor developmental progress educational needs. | At each visit

Neurologic

| • Monitor those w/seizures as clinically indicated.

• Assess for new manifestations such as seizures, changes in tone, movement disorders.

Neurobehavioral

| Assess for irritability /or sleep issues.

Feeding/

Gastrointestinal

| • Measurement of growth parameters

• Eval of nutritional status safety of oral intake

• Assessment for gastroesophageal reflux

Respiratory

| Monitor for evidence of aspiration, respiratory insufficiency.

Musculoskeletal

| Physical medicine, OT/PT assessment of mobility, self-help skills

Ophthalmologic involvement

| Monitor for strabismus. | Per treating ophthalmologist(s)

Assess need for low vision services. | At each visit

Gastrointestinal

| Monitor for constipation.1

Family/Community

| Assess family need for social work support (e.g., palliative/respite care, home nursing, other local resources), care coordination, or follow-up genetic counseling if new questions arise (e.g., family planning).

OT = occupational therapy; PT = physical therapy

1. Incidence of constipation has not been reported in individuals with FOXG1 syndrome; however, constipation is a common issue in most neurodevelopmental disorders.

Source: GeneReviews — "FOXG1 Syndrome"