Utility of Genetic Panels for Neuromuscular Disorders in a Tertiary Referral Center Neurology Clinic in Central Pennsylvania
Sarah Mauney1, Eleni Fafoutis1, Mansoureh Mamarabadi1
1Penn State Milton S. Hershey Medical Center
Objective:

To determine our clinic’s yield from genetic panel testing, uncover specific patient presentation patterns to help target genetic testing and further diagnostic studies.

Background:
Genetic testing panels have become frequently utilized in the neurology clinic. Recent AANEM guidelines state these tests are essential to diagnosis of a neuromuscular disease. Despite the overall benefit in uncovering a genetic diagnosis, previous studies have shown a wide range in utility.
Design/Methods:

In this retrospective analysis, data will be collected from a tertiary referral center in central Pennsylvania. Gene panel results from Invitae (San Francisco, California) and GeneDx (Gaithersburg, Maryland) with a total of roughly 900 patients will be evaluated in correlation with patient’s demographic data, phenotype, family history, age of onset, and electrodiagnostic studies.

Results:

To date, 317 patients with Invitae genetic panel testing results were reviewed. Mean age at symptom onset and time of genetic testing were 47 and 55 years, retrospectively.  Fifty-one percent were female. Eighty-three percent were white, 2.8% African-American, 2.2% Asian, 0.3% Hispanic, 11.7% others or unavailable per chart review. Patients were categorized into the following initial presentations: motor neuron disease (36%), neuropathy (22%), myopathy (18%), neuromuscular junction (1%), and other (28%). Electrodiagnostic studies showed the following patterns: large-fiber polyneuropathy (12%), myopathic (6%), motor neuron disease (31%), or nonspecific (53%). Genetic panels results were as follows: positive 14%, negative 42%, uncertain 38%, and carrier 7%. Of those patients with a positive panel result, significant family history was present in 74% and diagnostic EMG in 51%.

Conclusions:
Our preliminary results show that those with a positive gene panel result have higher percentage of significant family history and diagnostic EMG compared to those with an uncertain or negative panel results. We hope to develop an algorithm for gene panel testing in our clinic based on family history, electrodiagnostics, and biopsy results to increase diagnostic yield.
10.1212/WNL.0000000000205555