Landau-Kleffner syndrome (LKS) is diagnosed based on clinical features and the results of an electroencephalogram (EEG). An EEG is a recording of the electrical activity of the brain, and this can be completed when a child is asleep or awake. Children with LKS have abnormal electrical brain activity on both the left and right side of the brain.Brain MRI may be used to confirm that there is not another underlying cause of the symptoms. Audiometry (hearing study) may additionally be useful to confirm that the loss of language is not due to trouble with hearing. In some cases, LKS is originally misdiagnosed as autism, pervasive developmental disorder, hearing impairment, learning disability, auditory/verbal processing disorder, attention deficit disorder, intellectual disability, childhood schizophrenia, or emotional/behavioral problems.
Because a single underlying genetic cause has not been identified for all individuals with LKS, routine genetic testing is not completed at all centers. Researchers additionally suspect that mutations within the RELN, BSN, andEPHB2genes might be involved with the symptoms of LKS.
Last updated: 8/11/2017
Is genetic testing available for autism spectrum disorders (ASD)?
Genetic testing can determine the cause of some cases of ASD. Currently, a genetic cause can be identified in 20% to 25% of children with ASD. The cause of ASD in the remaining 75% to 80% remains unknown. Genetic testing can help determine if a person has ASD caused by a chromosome abnormality or a single-gene disorder. Large chromosome abnormalities have been seen in about 5% of those with ASD; smaller deletions or duplications of genetic material has been found in about 10-20%; single gene disorders have been found in about 5% of those with ASD. Despite intensive research, no specific gene has been solely associated with ASD.
GeneTests lists the names of laboratories that are performing genetic testing for ASD. To view the contact information for the clinical laboratories conducting testing, click here.
Please note: Most of the laboratories listed through GeneTests do not accept direct contact from patients and their families; therefore, if you are interested in learning more, you will need to work with a health care provider or a genetics professional.
Last updated: 10/19/2011
We hope this information is helpful. We strongly recommend you discuss this information with your doctor. If you still have questions, please
Conroy J, McGettigan PA, McCreary D, Shah N, Collins K, Parry-Fielder B, Moran M, Hanrahan D, Deonna TW, Korff CM, Webb D, Ennis S, Lynch SA, King MD. Towards the identification of a genetic basis for Landau-Kleffner syndrome. Epilepsia. Jun 2014; 55(6):858-65. http://onlinelibrary.wiley.com/doi/10.1111/epi.12645/full.