Cherie Chen, DO
Resident
NYU Rusk Rehabilitation
New York, New York, United States
Margaret O. Martinez, DO
Resident Physician
NYU Rusk Rehabilitation
River Vale, New Jersey, United States
Chun Maung, DO
Resident
New York University
New York, New York, United States
Hannah Park, DO
Resident
NYU Langone
New York, New York, United States
Renat Sukhov, MD
Attending
NYU Langone
New York, New York, United States
A 10-year-old girl with a history of congenital hydrocephalus, daily seizures and global developmental delay presented for physiatry follow up. Patient was found to have significant developmental regression. Patient was previously able to say simple words like mama but began to regress at around age 7-8 and now has become nonverbal. Patient was previously spastic but has since developed hypotonia. Patient’s 4-year-old brother with a history of motor and speech delay development was seen concurrently. Initially born with low muscle tone, he now presents with increased tone in bilateral lower extremities. Like his sister, he has significant speech regression. He could previously speak 5-6 words but currently only moans and points to objects. Both patients are actively getting treatment for frequent seizures. The parents are 1st degree cousins. Recent genetic study showed both siblings are homozygous in AP4B1, consistent with diagnosis for hereditary spastic paraplegia.
Discussions:
AP4B1 hereditary spastic paraplegia is a group of neurodevelopmental and slowly progressive neurological disorders that generally present with global developmental delay, including severe speech delay, hypotonia progressing to spastic paraplegia, and epilepsy/seizures. As of 2020, there have been 29 cases from 22 families reported, most of which with homozygous mutation. This could be differentiated from cerebral palsy, which has a slower, non-progressive course. Although speech delay has been frequently reported, these are the first reported cases where patients experience regression from their established developmental stage.
Conclusions:
Homozygous AP4B1 hereditary spastic paraplegia is a rare genetic disorder. Patients can often have significant functional improvement through rehabilitation and antiepileptic medication. However, there has yet to be a case reported on individuals who experience regression of speech and even become nonverbal. With the ever challenging disease progression, it is crucial to have pediatric physiatrists to optimize coordination of care.
