A novel case report of spinal muscular atrophy with progressive myoclonic epilepsy from Iran

Abstract

Spinal muscular atrophy (SMA) is a disorder characterized by decreased motor function due to the muscle atrophy in the background of degenerated anterior horn cells and motor cells of lower cranial nerves nuclei. The most frequent form is inherited as an autosomal recessive trait resulting from mutations in the survival motor neuron gene (SMN-1). On the other hand, a rare variant of this condition, named progressive myoclonic epilepsy subtype (SMA-PME) occurs in the result of a mutation in N-acylsphingosine amidohydrolase-1 gene (ASAH-1). The latter gene is responsible for lysosomal acid-ceramidase production. SMA-PME has been characterized by a progressive muscle weakness from ages 3-7 years, accompanied by epilepsy, an intractable seizure, and sometimes sensorineural hearing loss. In this report, we have presented a 15-year old female patient with SMA-PME that was attended to neurology clinic for a new onset tremor, seizure and proximal weakness in all limbs. We identified a homozygous mutation in exon II on her ASAH-1 gene [c.173C>T (p. Thr58Met)]. Also, a modest reduction was found in ceramidase-activity. As was expected patient`s seizures did not respond to conventional therapies.

Keywords: case report; muscular atrophy; myoclonic epilepsies; seizures.

Figure 1

H&E stain revealed atrophic fibers of round or angular shapes that arranged in small and large groups with hypertrophied fibers. Fascicular atrophy was seen. Nuclear clumps were noted.

Figure 2

ATPase reaction PH 4.35 revealed fiber type grouping with type-I fibers predominance. Atrophic fibers are mostly type-II.

Figure 3

Recorded EEG in the patient, It was recorded by bipolar setting, with sensitivity of 150 microvolt, high frequency filter of 70 Hz and low frequency filter of 1 Hz.There are generalized epileptiform 2.5–3 Hz irregular sharp and slow wave complexes.