Hedera et al. evaluated a family with intellectual disability and epilepsy that was inherited as an X-linked trait. Affected individuals had mild to moderate intellectual disability and tonic-clonic seizures. The age of onset for seizures varied from four to 14 months of age and the frequency ranged from 20 seizures per day to several seizures per month. There was no history of psychomotor regression once the seizures began. In addition to intellectual disability and seizures, the affected family members had developmental delay, speech delay, normal hearing, and no dysmorphic features.
A silent mutation (p.D107) in the ATP6AP2 (Xp11.4) gene was found to segregate in this family. This change was not identified in 1200 X-chromosomes of healthy controls.
For patients with suspected XLMR with epilepsy, sequence analysis is recommended as the first step in mutation identification. For patients in whom mutations are not identified by full gene sequencing, deletion/duplication analysis is appropriate.
- Confirmation of a clinical diagnosis of XLMR with epilepsy in an individual in whom sequence analysis was negative.
- Carrier testing in adults with a family history of XLMR with epilepsy in whom sequence analysis was negative.
Please note that a "backbone" of probes across the entire genome are included on the array for analytical and quality control purposes. Rarely, off-target copy number variants causative of disease may be identified that may or may not be related to the patient's phenotype. Only known pathogenic off-target copy number variants will be reported. Off-target copy number variants of unknown clinical significance will not be reported.
Submit only 1 of the following specimen types
Preferred specimen type: Whole Blood
Type: Whole Blood
Specimen Requirements:In EDTA (purple top) or ACD (yellow top) tube:
Infants (<2 years): 2-3 ml
Children (>2 years): 3-5 ml
Older Children & Adults: 5-10 ml
Specimen Collection and Shipping: Refrigerate until time of shipment. Ship sample within 5 days of collection at room temperature with overnight delivery.
Specimen Requirements:OrageneTM Saliva Collection kit (available through EGL) used according to manufacturer instructions.
Specimen Collection and Shipping: Store sample at room temperature. Ship sample within 5 days of collection at room temperature with overnight delivery.
- Sequence analysis of the ATP6AP2 gene is available and is required before deletion/duplication analysis.
- Custom diagnostic mutation analysis (KM) is available to family members if mutations are identified by targeted mutation testing or sequencing analysis.
- Prenatal testing is available only for known familial mutations to individuals who are confirmed carriers of mutations. Please contact the laboratory genetic counselor to discuss appropriate testing prior to collecting a prenatal specimen.
- X-Linked Intellectual Disability panels are available for 30, 60, and 90 genes.