DCX-related lissencephaly; DCX-related subcortical band heterotopia
|Clinical info||These are disorders of neuronal migration and generally the severity correlates with the degree of the brain anomaly. DCX-related lissencephaly primarily affects males who will present with infantile-onset of seizures and have severe intellectual disability and global delays. DCX-related subcortical band heterotopia is more common in female carriers. While most with SBH will have seizures, the cognitive ability can range from normal intelligence to severe intellectual disability.|
|Indications||Molecular testing is useful to confirm the diagnosis and to identify the disease causing mutation within a family to allow for carrier testing and prenatal diagnosis.|
The DCX gene is also included as a part of the 92-gene X-Linked Intellectual Disability panel.
Sequence variants of the DCX gene are found in about 38% of males with lissencephaly and accounts for almost 100% of families with X-linked lissencephaly. DCX mutations account for approximately 85% and 29% of SBH in females and males, respectively.
|Specimen Requirements||5 to 10 ml of peripheral blood collected in an EDTA (lavender top) Vacutainer tube is preferred. The minimal blood needed for reliable DNA isolation is 3 ml.|
|Transport||The specimen should be kept at room temperature and delivered via overnight shipping. FedEx is preferred. If shipment is delayed by one or two days, the specimen should be refrigerated and shipped at room temperature. Do not freeze the specimen. Samples collected on Friday can be safely designated for Monday delivery.|
|Turnaround time||6 weeks|
|Prenatal testing||Prenatal diagnosis is available if the familial mutation is known. Additional fees for cell culture and maternal cell contamination may apply. Maternal cell contamination studies are required for all prenatal molecular tests. Contact the laboratory prior to sending a prenatal specimen.|
|CPT Codes||Unknown mutation
|Cost||$900 for sequencing
$350 for known mutation
Molecular Diagnostic Lab
The Molecular Diagnostic Lab offers DNA analysis for many genetic disorders via gene sequencing, targeted mutation analysis, MLPA deletion/duplication testing, trinucleotide repeat analysis and next generation sequencing panels.