In contrast, CMV-related FS manifested different characteristics, including longer period of time between onset to nadir of illness (median 9 days); neurological deficits beyond the triad of FS, including sensory disturbance and limb weakness; increased severity in disability at the nadir of illness, and IgG3 subclass predominance of anti-GQ1b antibodies. This evidence concerns the gene IGHG3 and Feingold syndrome.