Subcortical band heterotopia

Alternate names

Double cortex syndrome; Double cortex; DC

Definition

Subcortical band heterotopia, also known as double cortex syndrome, is a condition of abnormal brain development that is present from birth. This condition which primarily affects females, occurs when neurons migrate to an area of the brain where they are not supposed to be (heterotopia), and form abnormal areas that appear as band-like clusters of white tissue underneath the gray tissue of the cerebral cortex (subcortical), creating the appearance of a double cortex

Epidemiology

More than 200 cases of subcortical band heterotopia have been reported in the scientific literature. Most affected individuals are female.

Cause

• Subcortical band heterotopia is most often caused by mutations in the DCX gene.
• Some cases may be caused by a small deletion on chromosome 17 involving the LIS1 gene.

Inheritance

X-linked dominant inheritance

The condition is inherited in an X-linked dominant pattern.

Signs and symptoms

• Symptoms associated with subcortical band heterotopia vary from severe intellectual disability and epilepsy to normal intelligence with mild or no epilepsy.
• Seizures occurring later in life and affecting only one side of the brain (focal seizures).
• Some affected individuals also have weak muscle tone (hypotonia), loss of fine motor skills such as using utensils, or behavioral problems.
• Subcortical band heterotopia is typically found when brain imaging is done following the onset of seizures, usually in adolescence or early adulthood.

Diagnosis

• A DCX-related disorder should be suspected in individuals with characteristic findings in brain magnetic resonance imaging (MRI) in combination with epileptic seizures and/or developmental delay or behavioral problems.
• A family history consistent with X-linked inheritance is an additional supportive finding.[1].

Treatment

• Antiepileptic drugs for epileptic seizures
• Deep brain stimulation may improve the seizure disorder in individuals with SBH
• Special feeding strategies in newborns with poor suck
• Physical therapy to promote mobility and prevent contractures
• Special adaptive chairs or positioners as needed
• Occupational therapy to improve fine motor skills and oral-motor control
• Participation in speech therapy, educational training, and enrichment programs.[2].

NIH genetic and rare disease info

• NIH info on Subcortical band heterotopia

Subcortical band heterotopia is a rare disease.