Question: What is (are) Subcortical band heterotopia ?
Answer: 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. Symptoms associated with subcortical band heterotopia vary from severe intellectual disability and epilepsy to normal intelligence with mild or no epilepsy. Subcortical band heterotopia is most often caused by mutations in the DCX gene. The condition is inherited in an X-linked dominant pattern. Some cases may be caused by a small deletion on chromosome 17 involving the LIS1 gene. Management consists of seizure control.
Source: GARD

Question: What are the symptoms of Subcortical band heterotopia ?
Answer: What are the signs and symptoms of Subcortical band heterotopia? The Human Phenotype Ontology provides the following list of signs and symptoms for Subcortical band heterotopia. If the information is available, the table below includes how often the symptom is seen in people with this condition. You can use the MedlinePlus Medical Dictionary to look up the definitions for these medical terms. Signs and Symptoms Approximate number of patients (when available) Cognitive impairment 90% Seizures 90% Hypertonia 50% Muscular hypotonia 50% Agenesis of corpus callosum - Ataxia - Death in infancy - Dysarthria - Incomplete penetrance - Infantile onset - Intellectual disability - Lissencephaly - Micropenis - Motor delay - Muscular hypotonia of the trunk - Nystagmus - Pachygyria - Postnatal growth retardation - X-linked inheritance - The Human Phenotype Ontology (HPO) has collected information on how often a sign or symptom occurs in a condition. Much of this information comes from Orphanet, a European rare disease database. The frequency of a sign or symptom is usually listed as a rough estimate of the percentage of patients who have that feature. The frequency may also be listed as a fraction. The first number of the fraction is how many people had the symptom, and the second number is the total number of people who were examined in one study. For example, a frequency of 25/25 means that in a study of 25 people all patients were found to have that symptom. Because these frequencies are based on a specific study, the fractions may be different if another group of patients are examined. Sometimes, no information on frequency is available. In these cases, the sign or symptom may be rare or common.
Source: GARD