We describe a child with Kabuki syndrome and suspected autoimmune encephalitis associated with CASPR-2 antibodies. 

Kabuki syndrome (KS) is a rare multisystem disorder characterized by distinctive facial features, growth delay, and intellectual impairment. Patients with KS are susceptible to immunodeficiency and autoimmunity, including hypogammaglobulinemia, thyroiditis, hemolytic anemia, idiopathic thrombocytopenic purpura, and vitiligo. Here, we report on the first case to our knowledge of a child with KS and autoimmune encephalitis (AE). 

Case report describing presenting symptoms, laboratory studies, neuroimaging, treatment, and clinical course of our patient. 

A 4-year-old boy with KS developed mycoplasma pneumonia requiring hospitalization. He exhibited depressed mental status, refractory status epilepticus, and paroxysmal sympathetic hyperactivity. MRI brain showed restricted diffusion and T2 hyperintensities in the bilateral mesial temporal lobes. CSF was normal. 

He underwent extensive evaluation for infectious, inflammatory, and metabolic disorders. Subsequently, he was found to be positive for serum CASPR-2 antibodies (CSF antibody not assessed). He received high dose IV steroids and plasma exchange without neurologic improvement. Repeat CSF showed mildly elevated protein to 47 mg/dl and negative CSF CASPR-2 antibodies. 

He received intensive, multidisciplinary inpatient rehabilitation and was followed closely by physiatrists, pediatric hospitalists, neuropsychologists, palliative care clinicians, nutritionists, and physical, speech, and occupational therapists. Due to lack of improvement, he received rituximab and monthly IVIG. Six months later, he remained non-verbal with minimal purposeful movements.  

To our knowledge, this is the first case of autoimmune encephalitis in a child with KS. This case report emphasizes the importance of early detection and treatment of AE given implications on long-term prognosis. Additionally, this case highlights the importance of a multidisciplinary approach to rehabilitation of children with neurodevelopmental disorders and severe acquired brain injuries as relates to therapy decisions, caregiver training, and need for discussion around goals of care.