SPINAL CORD AFFECTION IN LEIGH SYNDROME IN 4 PATIENTS

Objectives: Leigh syndrome (LS) is a heterogenous neurologic disease resulting from a disorder in the mitochondrial respiratory chain affecting infants and young children. Diagnosis is usually confirmed by radiologic or pathologic evidence of symmetric lesions in the basal ganglia, brainstem, and subthalamic nuclei. This syndrome can involve any level of the neuroaxis, resulting in a wide variety of presentations and also atypical clinical presentations. This case series describes four patients with atypical presentation of LS, presenting only spinal cord (SC) involvement.

Methods: We describe four patients with LS, with predominant SC involvement. There was not consanguinity in the families and two patients were siblings.

Results: The age of initial symptoms varied from 6 to 15 months and in three the disease presented initially with cervical spinal cord affection (hypotonia/hypertonia, neurogenic bladder arreflexia/hyperreflexia) progressing with repeated episodes; one, a boy now with 18 years old, developed slowly progressive spastic diplegia but his sister died at 2 years old during a metabolic decompensation. All patients had laboratory, radiologic, and/or pathologic findings consistent with LS. Magnetic ressonance imaging in three patients revealed: exclusive signal changes in SC (two patients) and also in brainstem (one patient). Postmortem examination in two patients evidenced typical lesions of LS confined to the SC in one and also affecting brainstem in the other.

Conclusion: Phenotypic variability is possible among siblings even when they possess the same genetic mutation as occurred in 2 siblings of this series. The diagnosis of LS should also be considered in all children with a progressive neurological syndrome involving the spinal cord. It is unclear whether patients with LS who present with predominant SC involvement are observed more commonly in any one enzyme deficiency.