KCNQ3-related disorders include benign familial neonatal epilepsy (BFNE) and benign familial infantile epilepsy (BFIE), seizure disorders that occur in children who typically have normal psychomotor development. An additional KCNQ3-related disorder involves developmental disability. In BFNE seizures begin in an otherwise healthy infant between days two and eight of life and spontaneously disappear between the first and the sixth to 12th month of life. Seizures are generally brief, lasting one to two minutes. Seizure types include tonic or apneic episodes, focal clonic activity, and autonomic changes. Motor activity may be confined to one body part, migrate to other regions, or generalize. Infants are well between seizures and feed normally. In BFIE seizures start in the first year of life, beyond the neonatal period, and disappear after age one to two years. Seizures are generally brief, lasting two minutes; they appear as daily repeated clusters. Seizure type is usually focal, but can be also generalized, causing diffuse hypertonia with jerks of the limbs, head deviation, or motor arrest with unconsciousness and cyanosis. Infants are normal between seizures and psychomotor development is usually normal. In the KCNQ3-related developmental disability phenotype, individuals present with intellectual disability with or without seizures and/or cortical visual impairment. As little clinical information on these individuals is available, the clinical presentation of KCNQ3-related developmental disability remains to be defined. [from GeneReviews]
- MedGen UID:
- 377707
- •Concept ID:
- C1852581
- •
- Disease or Syndrome