Jenna DeSimone
Senior Staff Physical Therapist Outpatient Physical Therapy RUSK Rehabilitation, USA
Title: GNE Myopathy: Recognizing Key Features to Optimize Physical Therapy Treatment in a Rare Myopathy
Biography
Biography: Jenna DeSimone
Abstract
Title: GNE Myopathy: Recognizing Key Features to Optimize Physical Therapy Treatment in a Rare Myopathy
Authors/Institutions: Jenna DeSimone PT, DPT, NCS, Rusk Rehabilitation, NYU Langone Health; Stephen Fischer, PT, DPT, NCS; Program Manager, Rusk Rehabilitation, NYU Langone Health
Abstract Body:
Background and Purpose: GNE myopathy, a rare autosomal recessive adult-onset disorder with progressive muscle atrophy and weakness, is due to a missing GNE/MNK enzyme, causing a sialic acid deficiency. Progressive distal limb weakness with a unique quadriceps sparring presentation is common. Investigational drug trials exist, but the disease currently has no cure. GNE myopathy has often been misdiagnosed, due to large exclusions in the population when histopathologic diagnostic criteria required multiple findings on muscle biopsy. Today the diagnosis relies on clinical presentation, including muscle imaging, and is confirmed by genetic studies. GNE myopathy presents with unique patterns of muscle dominance-quadriceps vs hamstrings, abductors vs adductors, hip extensors vs hip flexors, plantar flexors vs dorsiflexors, biceps vs triceps-with subjective reports of tripping, difficulty managing steps and rising from chairs. The authors have partook in data collection for a GNE myopathy IRB approved drug trial for 4 years, and are now seeing this population in the clinic. There is no literature available on GNE myopathy and physical therapy at this time. This report will identify the clinical characteristics of GNE myopathy and highlight the role of physical therapy (PT) in improving physical function, decreasing falls risk, and improving quality of life in this patient (pt) population.
Case Description: Pt is a 42-year-old female, noted a 6-year progressive decline in distal BLE weakness with increased falls. She was referred to PT for strengthening, balance and gait training, and to transition from soft over the counter AFOs to custom AFOs. She was not enrolled in a drug trial. Pt presented on evaluation with impaired strength, balance, endurance, and increased fear of falls. Pt received 30-60 min individual PT sessions 1-2 times per week for 32 sessions. Treatment emphasized strengthening dominant muscle groups to optimize function, balance training, and progressing high-level mobility with appropriate AFOs.
Outcomes: First and final outcome measures: 5 Time Sit to Stand 9 sec to 6 sec, Timed Up and Go 7.8 sec to 6.6 sec, Gait Speed (GS) self-selected 1.21 m/s to 1.49 m/s, GS fast 1.56 m/s to 1.79 m/s, Mini-BESTest 20/28 to 27/28, and Hi-MAT 27/54 to 29/54. Fall rate from x1 weekly to x1 in 3 months.
Discussion: Knowledge of GNE myopathy presentation and prognosis enabled PT to develop targeted strengthening programs to improve functional strength, decrease the risk of falls, and improve quality of life. Focused strengthening of dominant muscles with moderate intensity to prevent fatigue is essential in a population with difficulty generating new muscle fibers. Education on appropriate bracing to decrease falls risk and improve high-level mobility added to pt quality of life. More research is warranted as treatment options for pts with GNE myopathy progress.