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Disease Profile

Benign familial neonatal epilepsy

Prevalence
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.

Unknown

Age of onset

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ICD-10

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Inheritance

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

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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

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X-linked
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.

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

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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.

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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.

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Not applicable

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Other names (AKA)

Benign familial neonatal convulsions; Benign familial neonatal seizures; BFNS

Categories

Congenital and Genetic Diseases; Nervous System Diseases

Summary

The following summary is from Orphanet, a European reference portal for information on rare diseases and orphan drugs.
orphanet

Orpha Number: 1949

Definition
Benign familial neonatal epilepsy (BFNE) is a rare genetic epilepsy syndrome characterized by the occurrence of afebrile seizures in otherwise healthy newborns with onset in the first few days of life.

Epidemiology
Prevalence is currently unknown since this disorder is possibly overlooked. About 100 families have been reported to date.

Clinical description
Seizure onset is usually between the second and the eighth day of life, in otherwise healthy newborns. Seizures are mostly focal involving alternatively both sides of the body and apnea is frequently associated. Seizures can be isolated or in clusters, are generally brief and last 1-2 minutes. However, they can be very frequent, occurring up to 20 times a day, and may evolve into status epilepticus. Seizures can occur during wakefulness and/or sleep, and are of a mixed type, starting with tonic posture and apnea, and often progressing to clonic movements and motor automatisms. During the interictal period, neonates are neurologically normal, although some degree of sedation can be seen in response to anti-epileptic medications. Although most patients do receive antiepileptic treatment in the neonatal period, seizures have been shown to remit spontaneously after the first months of life, and are usually not seen after the first year of life. However, about 10 to 15% of patients have febrile or afebrile seizures later in childhood. Subsequent psychomotor development is normal.

Etiology
BFNE is a genetically heterogeneous disorder due to mutations in the KCNQ2 (20q13.33) and KCNQ3 (8q24) genes that both code for voltage-gated potassium channel subunits. Mutations in KCNQ2 are also responsible for KCNQ2-related epileptic encephalopathy, a severe form of neonatal epilepsy.

Diagnostic methods
Electroclinical events are suggestive of the disorder. Asymmetric tonic posturing associated with apnea and followed by focal or bilateral clonic jerking is the typical seizure type. In BFNE, neonates are neurologically normal and neurocognitive development is normal. Ictal electroencephalogram (EEG) may show focal interictal abnormalities, mainly over the central regions, but otherwise the EEG background is normal. The diagnosis is confirmed by genetic testing.

Differential diagnosis
Differential diagnosis includes benign familial neonatal-infantile seizures and benign familial infantile epilepsy.

Antenatal diagnosis
Prenatal diagnosis is possible if the disease-causing mutation has already been identified in the family.

Genetic counseling
Transmission is autosomal dominant with incomplete penetrance. Genetic counseling should be offered to affected families informing them of the 50% chance the offspring has of inheriting the disease-causing mutation and therefore being affected with the disorder. Rare cases are due to de novo mutations.

Management and treatment
The use of anticonvulsant therapy (e.g. phenobarbital, phenytoin, valproate, carbamazepine) is needed in most cases to stop seizures in the neonatal period, particularly in cases with very frequent seizures or status epilepticus. Usually, patients require treatment for the first 6-12 months of life. However, it is important for clinicians and family to be aware that some patients require treatment beyond 12 months of age.

Prognosis
Prognosis is good. Seizures normally disappear during the first year of life and patients do not display any neurological sequelae. Later seizures have been reported, including occasional febrile seizures and idiopathic epilepsy syndromes in childhood, in particular Rolandic epilepsy.

Visit the Orphanet disease page for more resources.

Symptoms

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:
HPO ID
80%-99% of people have these symptoms
Focal EEG discharges with secondary generalization
0011188
Focal tonic seizure
0011167
30%-79% of people have these symptoms
Apnea
0002104
Circumoral cyanosis
Bluish lips
0032556
Clonus
0002169
Focal autonomic seizure
0011154
Focal clonic seizure
0002266
Generalized tonic seizure
0010818
Limb myoclonus
0045084
5%-29% of people have these symptoms
Facial tics
Cramping of facial muscles
Facial spasms
Jerking of facial muscles
Mimic spasms
Spasms of facial muscles
Twitching of facial muscles

[ more ]

0011468
Gastroesophageal reflux
Acid reflux
Acid reflux disease
Heartburn

[ more ]

0002020
Muscular hypotonia of the trunk
Low muscle tone in trunk
0008936
Simple febrile seizure
0011171
1%-4% of people have these symptoms
Increased theta frequency activity in EEG
0031535
Status epilepticus
Repeated seizures without recovery between them
0002133

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.

In-Depth Information

  • Orphanet is a European reference portal for information on rare diseases and orphan drugs. Access to this database is free of charge.