Abstract
Purpose :
Stiff Person Syndrome (SPS) is a rare neurological disease associated with autoantibodies against glutamic acid decarboxylase (GAD) that causes muscle rigidity and spasms, but vision loss is not typical. We show that autoimmune retinopathy (AIR) associated with anti-GAD65 may be a rare, but debilitating feature of SPS.
Methods :
Retrospective, chart review, antibody testing by western blotting and immunohistochemistry.
Results :
Patient #1: A 55 year old white female was diagnosed with SPS with anti-GAD autoantibodies. She complained of color vision loss, and vision was 20/40 in both eyes (OU). Optical coherence tomography (OCT) showed normal macular anatomy. Full field electroretinography (ffERG) showed mild rod dysfunction with isoelectric waveform and attenuation of 30 Hz OU. Multifocal ERG (mfERG) showed macular cone dysfunction OU. At age 57, visual fields were severely constricted to 30 degrees centrally to III4e OU, and ERG showed worsened rod and cone dysfunction OU. She was diagnosed with AIR and monthly intravenous immunoglobulin (IVIg) was initiated to treat both her SPS and AIR. After 6 months, her fields enlarged to 130 degrees OU. After 9 months, her mfERG amplitudes normalized OU, and her ffERG improved OU. Patient #2: A 37 year old white female was diagnosed with SPS with anti-GAD autoantibodies. At age 62, she presented with a history of AIR and severe cone-rod dysfunction on ffERG, and was already on IVIg for SPS. She had hand-motion vision, severe macular attenuation on OCT, and worsened constriction of visual fields down to small peripheral islands OU. She was diagnosed with actively progressive AIR and her monthly IVIg dose was increased. After 3 months on high-dose IVIg, her V4e isopters enlarged by nearly 9 times OD and 3 times OS. Western blotting showed a presence of anti-GAD65 autoantibodies, and immunohistochemistry using human donor retina showed staining of the inner nuclear layer, inner plexiform layer and ganglion cell layer in both patients, which was consistent with the retinal staining pattern specific to anti-GAD65 antibodies.
Conclusions :
We demonstrate that AIR in patients with SPS with anti-GAD autoantibodies can cause rod-cone degeneration with peripheral field loss or cone-rod degeneration with macular attenuation and central vision loss. AIR in these two cases benefited from IVIg therapy, further supporting that AIR is an antibody-mediated disease.
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.