Subscribe to our mailing list

Get regular updates delivered to your email box.
Thank you for subscribing!

Rare Case of SMA Linked With Myoclonic Epilepsy Detailed in Report

Rare Case of SMA Linked With Myoclonic Epilepsy Detailed in Report
0
(0)

A 6-year-old boy was found to have a rare form spinal muscular atrophy (SMA) associated with progressive myoclonic epilepsy, a disease type known as “SMA plus” and not related to mutations in the causative gene for SMA, a case study reported.

SMA associated with progressive myoclonic epilepsy (SMA-PME) is a distinct disorder with its own clinical features,  the researchers noted.

The case report, “Spinal Muscular Atrophy and Progressive Myoclonic Epilepsy: A Rare Association,” appeared in the Journal of Neurosciences in Rural Practice

SMA is characterized by progressive weakness and atrophy of muscles due to loss of motor neurons. Most disease types are caused by mutations in the survival motor neuron 1 (SMN1) gene that encodes the SMN protein, which is essential for motor neuron survival.

In rare instances, however, SMA may be associated with progressive myoclonic epilepsy, a childhood seizure disorder that is unrelated to SMN genes. Progressive myoclonic epilepsy is characterized by progressive muscle weakness and atrophy that begins in childhood, followed by the development of myoclonic seizures — brief muscle “jerks” or spasms. SMA plus syndrome has previously been tied to mutations in the ASAH1 gene. 

ASAH1 provides instructions to make an enzyme called acid ceramidase. This enzyme is usually found inside lysosomes — small, specialized cell compartments that digest and recycle different types of molecules — where it helps break down fatty molecules called ceramides.

Researchers in India described the case of a 6-year-old who began experiencing progressive muscle weakness and wasting in his limbs at age 2, delaying his motor milestones. Sudden, jerky muscle movements, characteristic of myoclonic seizures, were evident by the time he reached age 3.5. Months later, as a 4 year old, he had difficulty speaking and swallowing.

As the frequency of the muscle jerks increased, the boy developed postural tremors and twitches involving both hands, as well as periods of troubled awareness. A muscle examination found wasting in all limbs and diminished deep tendon reflexes, both characteristic of SMA. 

Further analysis found abnormal electrical activity of the muscles, consistent with widespread loss of motor nerve connections. Electroencephalogram (EEG) showed brain activity consistent with generalized epilepsy. 

Genetic analysis failed to identify SMN gene mutations, indicative of SMA with progressive myoclonic epilepsy not associated with the SMN gene.

The boy was treated with valproic acid and clobazam, which lessened myoclonic seizures and normalized EEG tests.

“To best of our knowledge, 44 cases of SMA-PME-like clinical presentation have been reported to date … Muscle weakness and wasting along with myoclonic jerks and seizures were common in all the reported cases of SMA-PME despite the differences in attributes like age of onset, severity and progression of the disease,” the researcher wrote. 

“SMA with myoclonic epilepsy, unrelated to SMN gene, is a unique condition with its own clinical and electrophysiological features. Study of additional cases is also required to understand the genetic and pathophysiological [disease features] basis of SMA-PME,” they concluded.

Aisha Abdullah received a B.S. in biology from the University of Houston and a Ph.D. in neuroscience from Weill Cornell Medical College, where she studied the role of microRNA in embryonic and early postnatal brain development. Since finishing graduate school, she has worked as a science communicator making science accessible to broad audiences.
Total Posts: 86

Ana holds a PhD in Immunology from the University of Lisbon and worked as a postdoctoral researcher at Instituto de Medicina Molecular (iMM) in Lisbon, Portugal. She graduated with a BSc in Genetics from the University of Newcastle and received a Masters in Biomolecular Archaeology from the University of Manchester, England. After leaving the lab to pursue a career in Science Communication, she served as the Director of Science Communication at iMM.

×
Aisha Abdullah received a B.S. in biology from the University of Houston and a Ph.D. in neuroscience from Weill Cornell Medical College, where she studied the role of microRNA in embryonic and early postnatal brain development. Since finishing graduate school, she has worked as a science communicator making science accessible to broad audiences.
Latest Posts
  • progressive myoclonic epilepsy

How useful was this post?

Click on a star to rate it!

Average rating 0 / 5. Vote count: 0

No votes so far! Be the first to rate this post.

As you found this post useful...

Follow us on social media!

We are sorry that this post was not useful for you!

Let us improve this post!

Tell us how we can improve this post?