2023 American Academy of Neurology Abstract Website

Objective:

N/A

Background:

Cerebral palsy (CP) manifests after a perinatal injury, but symptoms can progress with age. A family history of CP phenotype or early progression should alert the clinician to potential CP mimics like the hereditary spastic paraplegias (HSPs), a heterogeneous group of conditions with representatives of all modes of genetic inheritance.

Design/Methods:

N/A

Results:

The patient was born at full term with no perinatal complications. He had delayed motor development, beginning to walk at 2 years of age, and had learning disability requiring modified classes in school. Gait difficulties became apparent in adolescence, progressing to being wheelchair bound in adulthood. He presented to our clinic at age 48 carrying a diagnosis of CP, with bilateral leg spasticity and urinary urgency/incontinence. On camera, he was sitting with leg contractures and dependent edema. No associated oculomotor, facial, or arm weakness, no ataxia or tremor, and no speech or vision abnormalities were detected. Neither of his parents or his nine siblings (7 sisters and 2 brothers) had similar symptoms. He did report having a maternal uncle and nephew with a similar phenotype. MRI brain and thoracic spine were obtained but were unremarkable. Adrenomyeloneuropathy (AMN) was considered but laboratory and genetic testing were not revealing. A genetic panel for hereditary spastic paraplegias was ordered, detecting a pathogenic heterozygous variant, SPAST c.1496G>A (p.Arg499His), causative for SPG4.

Conclusions:

This case highlights the incomplete penetrance of SPG4 and supports the concept of female carriers of SPG4 being less penetrant, as none of his 7 sisters had clinical symptoms. When the presented history and exam are not consistent with a diagnosis of CP, the clinician should search for potential mimics. Inconsistencies include lack of history of perinatal insult, onset of symptoms outside of the perinatal period, and progressive symptoms. In particular, treatable CP mimics, such as adrenomyeloneuropathy, cannot be missed.