Abstract Details

Title Early-onset Hereditary Spastic Paraplegia (SPG3A) Misdiagnosed as Diplegic Cerebral Palsy in a Child With Multigenerational Family History and Normal Birth

Topic Neuromuscular and Clinical Neurophysiology (EMG)

Presentation(s) P3 - Poster Session 3 (5:00 PM-6:00 PM)

Poster/Presentation
Number 9-005

Objective To illustrate the critical role of genomic diagnostics in differentiating hereditary spastic paraplegia (HSP) from spastic diplegic cerebral palsy (CP) in a pediatric patient with a normal birth history and strong family history of motor impairment.

Background

Hereditary Spastic Paraplegias (HSPs) are insidious genetic disorders defined by progressive lower limb spasticity. Their clinical presentation closely resembles spastic diplegia, making HSPs the classic “CP mimic” and leading to frequent misdiagnosis. Among these, SPG3A, caused by mutations in the ATL1 gene, represents the most common autosomal dominant childhood form. This diagnostic confusion has profound consequences: mistaking a progressive inherited disorder for a static condition like CP can delay accurate prognosis, misdirect therapy, and deny families essential genetic counseling.

Design/Methods We report a 3-year-old boy whose progressive spasticity and developmental delays were initially attributed to CP. Two critical clues—an unremarkable term birth and a striking three-generation family history of gait impairment—prompted renewed evaluation. These findings led to whole exome sequencing (WES) for the patient and parents.

Results WES identified a pathogenic ATL1 variant (p.Val253Phe), confirming Hereditary Spastic Paraplegia type 3A. This single molecular finding unified the diagnosis for the child, his affected father, and two brothers, reframing their medical history from presumed birth injury to a shared inherited condition.

Conclusions Hereditary Spastic Paraplegia should be recognized as a key differential diagnosis in pediatric spastic diplegia, particularly when perinatal history is normal or family history is positive. This case underscores the importance of early genomic testing to reduce diagnostic delays and avoid misdiagnosis. Establishing a molecular diagnosis enables precise prognostication, targeted therapies, and informed genetic counseling.

Authors/Disclosures
Ahmed A. Mohamed, MD PRESENTER	Dr. Mohamed has nothing to disclose.
Eric C. Strong, MD (Geisinger Medical Center)	Dr. Strong has received personal compensation in the range of $500-$4,999 for serving on a Scientific Advisory or Data Safety Monitoring board for Sarepta.

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