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Abstract Details

Comparing Clinical Characteristics and Outcomes of Anti-GAD65-associated Pure Cerebellar Ataxia and Stiff Person Spectrum Disorders
Autoimmune Neurology
P1 - Poster Session 1 (8:00 AM-9:00 AM)
14-002

Cerebellar ataxia is a well-recognized manifestation of anti-GAD65-associated neurological autoimmunity and can occur in isolation or as part of stiff person spectrum disorders (SPSD). Cerebellar dysfunction in SPSD may portend a poorer prognosis, so further investigation is needed to determine risk factors and predictors of outcome compared to anti-GAD65-associated pure cerebellar ataxia (pCA).

To compare anti-GAD65-associated neurological disorders that impact cerebellar function.

A retrospective review was completed from 1997-2023 to identify anti-GAD65 antibody seropositive individuals with cerebellar involvement at our SPS Center. Subjects were divided into two groups based on whether they had cerebellar dysfunction in the presence (SPSD; SPS-plus and progressive encephalomyelitis with rigidity and myoclonus [PERM]) or absence (pCA) of classical SPS features. Non-parametric statistics were used to compare groups.

Sixty-six eligible patients were identified among 294 screened subjects (57 SPSD, 9 pCA). The pCA group was older compared to SPSD (median 69 years [range 46-80] vs. 47 [18-69], p < 0.05), but otherwise did not differ demographically. Presenting symptoms were as expected based on phenotype. The majority of pCA and SPSD patients had anti-GAD65 antibodies in CSF (>80%) with high titers in serum (>70%). Cerebellar atrophy on MRI was present in some patients in each group. Initial median timed 25-foot walk times (11 s [6.8-39] vs. 9.5 s [3.8-56.5], p < 0.05) and modified Rankin scales (4 [3-4] vs. 3 [1-5], p<0.05) showed more severe disability in the pCA group compared to SPSD. These measures did not differ significantly at last follow-up. Rates of symptomatic and immunomodulatory treatment were similar in each group.

Anti-GAD65-associated neurological conditions with cerebellar involvement have moderate-to-severe disability irrespective of subtype, however pCA patients may have more ambulatory disability based on objective evaluation of walking speed compared to SPSD. Further studies are needed to determine factors underlying inter-individual phenotypic variation across anti-GAD65-associated conditions.

Authors/Disclosures
Jonathan Krett, MD (Johns Hopkins University School of Medicine)
PRESENTER
Dr. Krett has nothing to disclose.
Ashley Miles (The Johns Hopkins Hospital) No disclosure on file
Herbert Chen No disclosure on file
Yujie Wang, MD (UW Northwest) Dr. Wang has received personal compensation in the range of $500-$4,999 for serving as a Consultant for TG Therapeutics. The institution of Dr. Wang has received research support from Genentech.
Scott D. Newsome, DO, FAAN (Johns Hopkins Hospital) Dr. Newsome has received personal compensation in the range of $500-$4,999 for serving on a Scientific Advisory or Data Safety Monitoring board for Biogen. Dr. Newsome has received personal compensation in the range of $10,000-$49,999 for serving on a Scientific Advisory or Data Safety Monitoring board for Genentech. Dr. Newsome has received personal compensation in the range of $500-$4,999 for serving on a Scientific Advisory or Data Safety Monitoring board for Novartis. Dr. Newsome has received personal compensation in the range of $500-$4,999 for serving on a Scientific Advisory or Data Safety Monitoring board for EMD Serono. Dr. Newsome has received personal compensation in the range of $500-$4,999 for serving on a Scientific Advisory or Data Safety Monitoring board for Greenwich Biosciences. Dr. Newsome has received personal compensation in the range of $500-$4,999 for serving on a Scientific Advisory or Data Safety Monitoring board for Bristol Myers Squibb. Dr. Newsome has received personal compensation in the range of $500-$4,999 for serving on a Scientific Advisory or Data Safety Monitoring board for Horizon Therapeutics. Dr. Newsome has received personal compensation in the range of $500-$4,999 for serving on a Scientific Advisory or Data Safety Monitoring board for TG Therapeutics. The institution of Dr. Newsome has received research support from Biogen. The institution of Dr. Newsome has received research support from Genentech/Roche. The institution of Dr. Newsome has received research support from Department of Defense. The institution of Dr. Newsome has received research support from Patient Centered Outcomes Research Institute. The institution of Dr. Newsome has received research support from National MS Society. The institution of Dr. Newsome has received research support from The Stiff Person Syndrome Research Foundation. The institution of Dr. Newsome has received research support from Lundbeck. Dr. Newsome has received personal compensation in the range of $10,000-$49,999 for serving as a Lead PI for Clinical Trial with Roche.