Mutação no gene scn1a e suas diferentes expressões fenotípicas - comparação de dois casos

Abstract

INTRODUCTION: Heterozygous mutations in the SCN1A gene are linked to a wide spectrum of epileptic disorders, ranging from self-limited conditions to epileptic encephalopathies, such as Dravet Syndrome. Seizure control is important to prevent both sudden death and morbidity associated with prolonged seizures. Current evidence suggests that sodium-channel blockers should be avoided. OBJECTIVES: To report on two cases of patients with a mutation in the SCN1A gene associated with Dravet Syndrome, emphasizing the importance of genetic testing for the diagnosis, prognosis, and correct choice of antiepileptic medications. CASE REPORT: Case 1: male patient with onset of seizures at four months old following vaccination. After this, he developed prolonged generalized seizures and, over time, other types of seizures. He also developed a severe intellectual deficit and drug-resistant epilepsy exacerbated by infections and use of sodium-channel blockers. Case 2: female patient with first episode of seizure at 26 days. At 13 months, she developed prolonged generalized crises exacerbated by small temperature variations and euphoria or irritability. Aged two, she had an episode of prolonged status epilepticus. As a result, she developed hypoxic-ischemic encephalopathy and drug-resistant epilepsy. DISCUSSION: The two patients have a mutation in the SCN1A gene associated with Dravet syndrome and their clinical history reveal similar and discrepant points. The most significant contributions of genetic testing are the identification of precipitating factors, greater attention to the possibility of unfavorable evolution, and guidance for choosing anticonvulsants, including avoidance of sodium-channel blockers.

Keywords

• loss of function mutation
• epilepsy
• nav1.1 voltage-gated sodium channel