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Disease Profile

Landau-Kleffner syndrome

Prevalence estimates on Rare Medical Network websites are calculated based on data available from numerous sources, including US and European government statistics, the NIH, Orphanet, and published epidemiologic studies. Rare disease population data is recognized to be highly variable, and based on a wide variety of source data and methodologies, so the prevalence data on this site should be assumed to be estimated and cannot be considered to be absolutely correct.


US Estimated

Europe Estimated

Age of onset






Autosomal dominant A pathogenic variant in only one gene copy in each cell is sufficient to cause an autosomal dominant disease.


Autosomal recessive Pathogenic variants in both copies of each gene of the chromosome are needed to cause an autosomal recessive disease and observe the mutant phenotype.


dominant X-linked dominant inheritance, sometimes referred to as X-linked dominance, is a mode of genetic inheritance by which a dominant gene is carried on the X chromosome.


recessive Pathogenic variants in both copies of a gene on the X chromosome cause an X-linked recessive disorder.


Mitochondrial or multigenic Mitochondrial genetic disorders can be caused by changes (mutations) in either the mitochondrial DNA or nuclear DNA that lead to dysfunction of the mitochondria and inadequate production of energy.

Multigenic or multifactor Inheritance involving many factors, of which at least one is genetic but none is of overwhelming importance, as in the causation of a disease by multiple genetic and environmental factors.


Not applicable


Other names (AKA)

Acquired aphasia with convulsive disorder; LKS; Acquired epileptiform aphasia;


Congenital and Genetic Diseases; Eye diseases; Nervous System Diseases


Landau-Kleffner syndrome (LKS) is a rare neurological syndrome characterized by the sudden or gradual development of aphasia (the inability to understand or express language) and recurrent seizures (epilepsy). Children with LKS typically develop normally until signs and symptoms of the syndrome begin to develop between age 2 and 8 years.[1][2] Males are more often affected by LKS than females.[1] 

In about 20% of people with LKS, mutations (changes) in the GRIN2A gene have been identified. The syndrome is inherited in an autosomal dominant manner. In other cases, the syndrome may be caused by changes to other unidentified genes.[3] LKS is diagnosed when a doctor sees clinical features that are consistent with the syndrome such as a loss of speech and an electroencephalogram (EEG) that shows specific kinds of seizure activity. Genetic testing can be used to confirm if there is a mutation in GRIN2A, but this testing is not done routinely.[2]

Treatment for LKS usually consists of medications such as anticonvulsants and corticosteroids to help prevent seizures. Speech therapy should also be started promptly in order to ensure the best long-term outlook for children with LKS.[2]


Landau-Kleffner syndrome (LKS) is characterized by the sudden or gradual development of aphasia (the inability to understand or express language). Children affected with LKS have developed normally until signs and symptoms begin between the ages of 2 and 8.[1][2] This syndrome is also characterized by an abnormal electroencephalogram (EEG), especially during sleep.[4] About 70% of children with LKS have seizures.[3] The seizures associated with LKS are known as complex partialgeneralized clonic, and atypical absence seizures and are generally easy to control with medications. 

Some children with Landau-Kleffner syndrome may develop behavioral problems including hyperactivityattention deficits, temper outbursts, impulsivity, and/or withdrawn behaviors.[4] Some children with Landau Kleffner syndrome may also have intellectual disability.[3] As researchers continue to learn more about LKS, it seems that there may be a wider variety of signs and symptoms associated with this syndrome than originally thought. There may be a variability of symptoms associated with LKS even within the same family.[5]

This table lists symptoms that people with this disease may have. For most diseases, symptoms will vary from person to person. People with the same disease may not have all the symptoms listed. This information comes from a database called the Human Phenotype Ontology (HPO) . The HPO collects information on symptoms that have been described in medical resources. The HPO is updated regularly. Use the HPO ID to access more in-depth information about a symptom.

Medical Terms Other Names
Learn More:
5%-29% of people have these symptoms
Global developmental delay
Intellectual disability
Mental deficiency
Mental retardation
Mental retardation, nonspecific

[ more ]

Percent of people who have these symptoms is not available through HPO
Difficulty finding words
Losing words
Loss of words

[ more ]

Attention deficit hyperactivity disorder
Attention deficit
Attention deficit disorder
Attention deficit-hyperactivity disorder
Attention deficits
Childhood attention deficit/hyperactivity disorder

[ more ]

Autosomal dominant inheritance
Behavioral abnormality
Behavioral changes
Behavioral disorders
Behavioral disturbances
Behavioral problems
Behavioral/psychiatric abnormalities
Behavioural/Psychiatric abnormality
Psychiatric disorders
Psychiatric disturbances

[ more ]

Delayed speech and language development
Deficiency of speech development
Delayed language development
Delayed speech
Delayed speech acquisition
Delayed speech development
Impaired speech and language development
Impaired speech development
Language delay
Language delayed
Language development deficit
Late-onset speech development
Poor language development
Speech and language delay
Speech and language difficulties
Speech delay

[ more ]

EEG with centrotemporal focal spike waves
Incomplete penetrance
Speech apraxia
Variable expressivity


In some cases, Landau-Kleffner syndrome is thought to be caused by mutations(changes) in the GRIN2A  gene. This gene provides instructions to the body to make a protein that sends signals to the nerve cells (neurons) in the brain. When these signals are not being transmitted properly, they may affect the ability to understand or express language.[3] These signals may also cause receptors in the brain to be turned on abnormally, resulting in seizures.[3] It has been proposed that the seizures associated with LKS may cause damage to the parts of the brain responsible for speech, but this hypothesis has not been confirmed.[5]

In about 80% of people diagnosed with LKS, no mutation is found in the GRIN2A gene. In these cases, it is thought that LKS could be caused by mutations in other genes or an interaction between genes and the environment.[3] It has also been proposed that in some cases LKS may be the result of an autoimmune response that occurs when the body attacks itself as if it were an infection.[5]


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.[1] 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.[7] In some cases, LKS is originally misdiagnosed as autismpervasive developmental disorderhearing impairment, learning disability, auditory/verbal processing disorder, attention deficit disorderintellectual disability, childhood schizophrenia, or emotional/behavioral problems.[3]

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 RELNBSNand EPHB2  genes might be involved with the symptoms of LKS.[4][8] 


The treatment for Landau-Kleffner syndrome may vary depending on the specific symptoms present in each person. Children who have seizures may be prescribed anticonvulsant medications and corticosteroids may be recommended.[1] In some cases, immunotherapy may improve speech and seizures.[9] In rare cases in which other treatment options for seizures have not been successful, a surgery called multiple subpial transection may help to relieve seizures.[2]

Speech therapy should be initiated as soon as possible to help children regain speech.[1] Speech therapists may also recommend helping children learn sign language to help them find new ways to communicate.[4] Special education may also be necessary in some cases.[4]


Support and advocacy groups can help you connect with other patients and families, and they can provide valuable services. Many develop patient-centered information and are the driving force behind research for better treatments and possible cures. They can direct you to research, resources, and services. Many organizations also have experts who serve as medical advisors or provide lists of doctors/clinics. Visit the group’s website or contact them to learn about the services they offer. Inclusion on this list is not an endorsement by GARD.

Organizations Supporting this Disease

    Organizations Providing General Support

      Learn more

      These resources provide more information about this condition or associated symptoms. The in-depth resources contain medical and scientific language that may be hard to understand. You may want to review these resources with a medical professional.

      Where to Start

      • MedlinePlus was designed by the National Library of Medicine to help you research your health questions, and it provides more information about this topic.
      • Genetics Home Reference (GHR) contains information on Landau-Kleffner syndrome. This website is maintained by the National Library of Medicine.
      • The National Institute of Neurological Disorders and Stroke (NINDS) collects and disseminates research information related to neurological disorders. Click on the link to view information on this topic.
      • The National Organization for Rare Disorders (NORD) has a report for patients and families about this condition. NORD is a patient advocacy organization for individuals with rare diseases and the organizations that serve them.

        In-Depth Information

        • Medscape Reference provides information on this topic. You may need to register to view the medical textbook, but registration is free.
        • The Monarch Initiative brings together data about this condition from humans and other species to help physicians and biomedical researchers. Monarch’s tools are designed to make it easier to compare the signs and symptoms (phenotypes) of different diseases and discover common features. This initiative is a collaboration between several academic institutions across the world and is funded by the National Institutes of Health. Visit the website to explore the biology of this condition.
        • Online Mendelian Inheritance in Man (OMIM) is a catalog of human genes and genetic disorders. Each entry has a summary of related medical articles. It is meant for health care professionals and researchers. OMIM is maintained by Johns Hopkins University School of Medicine. 
        • Orphanet is a European reference portal for information on rare diseases and orphan drugs. Access to this database is free of charge.
        • PubMed is a searchable database of medical literature and lists journal articles that discuss Landau-Kleffner syndrome. Click on the link to view a sample search on this topic.


          1. Landau-Kleffner Syndrome Information Page. National Institute of Neurological Disorders and Stroke. https://www.ninds.nih.gov/Disorders/All-Disorders/Landau-Kleffner-Syndrome-Information-Page. Accessed 8/6/2017.
          2. Loddenkemper T and Sanchez Fernandez I. Landau-Kleffner syndrome. Orphanet. April 2014; https://www.orpha.net/consor/cgi-bin/OC_Exp.php?lng=en&Expert=98818.
          3. Epilepsy-aphasia spectrum. Genetics Home Reference. November 2016; https://ghr.nlm.nih.gov/condition/epilepsy-aphasia-spectrum.
          4. Mantovani JF. Landau Kleffner Syndrome. National Organization for Rare Disorders (NORD). 2015; https://rarediseases.org/rare-diseases/landau-kleffner-syndrome/.
          5. Neiman ES and Seyffert M. Acquired Epileptic Aphasia. Medscape. December 9, 2015; https://emedicine.medscape.com/article/1176568.
          6. Epilepsy, Focal, With Speech Disorder And Or Without Mental Retardation; FESD. Online Mendelian Inheritance in Man. May 11, 2017; https://www.omim.org/entry/245570.
          7. Myers KA and Scheffer IE. GRIN2A-Related Speech Disorders and Epilepsy. GeneReviews. September 29, 2016; https://www.ncbi.nlm.nih.gov/books/NBK385627/.
          8. 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. https://onlinelibrary.wiley.com/doi/10.1111/epi.12645/full.
          9. Fainberg N, Harper A, Tchapyjnikov D, and Mikati MA. Response to immunotherapy in a patient with Landau-Kleffner syndrome and GRIN2A mutation. Epileptic Disorders. March 2016; 18(1):97-100. https://www.jle.com/fr/revues/epd/e-docs/response_to_immunotherapy_in_a_patient_with_landau_kleffner_syndrome_and_grin2a_mutation_306244/article.phtml?tab=texte.

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