Immune-mediated steroid-responsive epileptic spasms and epileptic encephalopathy associated with VGKC-complex antibodies

Abstract

Autoantibodies that bind to voltage-gated potassium-channel complex proteins (VGKC-complex antibodies) occur frequently in adults with limbic encephalitis presenting with cognitive impairment and seizures. Recently, VGKC-complex antibodies have been described in a few children with limbic encephalitis, and children with unexplained encephalitis presenting with status epilepticus. We report a case of infantile-onset epileptic spasms and developmental delay compatible with epileptic encephalopathy. Our patient was a female infant, aged 4months at presentation. She had evidence of immune activation in the central nervous system with elevated cerebrospinal fluid neopterin and mirrored oligoclonal bands, which prompted testing for autoantibodies. VGKC-complex antibodies were elevated (201pmol/L, normal<100), but extended antibody testing, including leucine-rich glioma-inactivated 1 (LGI1) and contactin-associated protein 2 (CASPR2), was negative. The patient showed a partial response to steroid treatment, which was started late in the disease course. On review at 13months of age, her development was consistent with an age of 5 to 6months. These results suggest that VGKC-complex antibodies might represent a marker of immune therapy responsiveness in a subgroup of patients with infantile epileptic encephalopathy. © The Authors. Developmental Medicine and Child Neurology © 2011 Mac Keith Press.