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Disease Profile

Convulsions, benign familial infantile, 1

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

Infancy

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ICD-10

G40.3

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.

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)

BFIC1; BFIC; BFIS1;

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.
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Orpha Number: 306

Definition
Benign familial infantile epilepsy (BFIE) is a genetic epileptic syndrome characterized by the occurrence of afebrile repeated seizures in healthy infants, between the third and eighth month of life.

Epidemiology
Although BFIE cases have been reported worldwide, prevalence and incidence remain unknown. In an Argentinian case series, BFIE have been listed as the third most common type of epilepsy in the first two years of life.

Clinical description
Seizures usually occur between 3 to 8 months of life, with clusters (8-10 a day) of repeated and brief episodes (2-5 minutes) over a few days. They are usually focal but can sometimes become generalized. Patients present with motor arrest, unresponsiveness, head and/or eye deviation to one side, staring, fluttering of eyelids, grunting, cyanosis, diffuse hypertonia and unilateral or bilateral clonic jerks of the limbs. During the interictal period, patients regain full consciousness and activity. Psychomotor development is normal. A family history of the same epilepsy is a constant finding. A syndrome called familial infantile convulsions and choreoathetosis (ICCA; see this term) has been observed in which BFIE patients present in childhood and/or adolescence with choreoathetotic dyskinetic attacks occurring spontaneously or following diverse stimuli (e.g. exercise, stress). In some rare cases, BFIE has been associated with familial or sporadic hemiplegic migraine.

Etiology
BFIE is a genetically heterogeneous disease. In the majority of cases, mutations in the proline-rich transmembrane protein 2 (PRRT2) gene located at 16p11.2 have been found. This gene encodes a membrane protein that interacts with the presynaptic protein SNAP-25. Mutations have also been found in the SCN2A gene (2q24.3) encoding the brain sodium channel NaV1.2 and rarely in the KCNQ2 (20q13.33) and KCNQ3 (8q24) genes both encoding potassium channels. Additionally, three other chromosomal loci have been identified that are mapped to chromosome 19q, 16p and 1p.

Diagnostic methods
Family history can orient the diagnosis which is based on electroencephalography (EEG) and video recordings. Ictal EEG shows that partial seizures originate from the parietal-occipital region and that the side of the hemisphere involved can vary between episodes. Seizures can sometimes spread and involve the entire brain. During a cluster of seizures, postictal EEG shows lateralized occipito-parietal delta waves and spikes. Outside the cluster, waking and sleeping interictal EEG is normal. Interictal neurological examination and brain imaging (brain CT and/or MRI) are normal. Genetic testing confirms the diagnosis.

Differential diagnosis
Differential diagnosis includes benign familial neonatal-infantile seizures (see this term), an epileptic syndrome with an intermediate onset between the neonatal and infantile age that shares overlapping clinical characteristics with BFIE and that is mainly due to mutations in the SCN2A gene. Other differential diagnoses are benign non-familial infantile seizures, benign infantile seizures associated with mild gastroenteritis and benign infantile focal epilepsy with midline spikes and waves during sleep (BIMSE) (see these terms).

Genetic counseling
BFIE is transmitted as an autosomal dominant trait with incomplete penetrance.

Management and treatment
With anti-epileptic treatment (e.g. carbamazepine, valproate, phenobarbital), symptoms quickly disappear and no other type of epilepsy has been reported to reappear. In patients with a clear familial history the treatment can be interrupted within a few months.

Prognosis
Prognosis is good. Seizures normally disappear after the first year of life and patients do not display any neurological sequelae.

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
Normal interictal EEG
0002372
30%-79% of people have these symptoms
Apnea
0002104
Bilateral tonic-clonic seizure with focal onset
0007334
Focal clonic seizure
0002266
Focal impaired awareness seizure
0002384
Focal tonic seizure
0011167
Generalized clonic seizure
0011169
Generalized tonic seizure
0010818
5%-29% of people have these symptoms
Cyanosis
Blue discoloration of the skin
0000961
Generalized non-motor (absence) seizure
Brief seizures with staring spells
0002121
Hypertonia
0001276
Limb myoclonus
0045084
1%-4% of people have these symptoms
Interictal epileptiform activity
0011182
Simple febrile seizure
0011171
Status epilepticus
Repeated seizures without recovery between them
0002133
Percent of people who have these symptoms is not available through HPO
Autosomal dominant inheritance
0000006
Focal-onset seizure
Seizure affecting one half of brain
0007359
Generalized-onset seizure
0002197

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

  • 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 Convulsions, benign familial infantile, 1. Click on the link to view a sample search on this topic.