Neurological Disorders

In a recent article Kytövuori et al. reported a Finnish family with phenotypically variable multiorgan disease manifesting in the brain, ears, and endocrine organs, due to the variant m.7510T>C in the MT-TS1 (tRNA(Ser)) gene with high heteroplasmy. We have the following comments and concerns.

Dystonia is one of the most common movement disorders, but the pathogenesis of primary dystonia is not fully understood. One of the proposed pathomechanisms is the deficiency or dysfunction of ATP-dependent Menkes protein responsible for the extracellular transport of copper within subcortical nuclei, the lack of which could lead to increased accumulation of copper in the lenticular nucleus (LN). In 1995, Naumann et al. performed transcranial sonography (TCS) on patients with dystonia for the first time. Other researchers confirmed more frequent occurrence of hyperechogenic LN more than 70% patients with cervical dystonia. The aim of our study was therefore to evaluate the prevalence of hyperechogenic changes in lenticular nucleus of the brain in patients with cervical dystonia. 108 patients were considered eligible for inclusion; 42 of them were subsequently excluded due to occurrence of exclusion criteria. Thus, the study involved 66 patients and 71 controls. Hyperechogenicity of the lenticular nucleus was found more often in patients with cervical dystonia than in controls (p<0.0001). It was unilateral in majority of patients (75.8%). The average surface area of hyperechogenic changes is bigger in dystonic patients compare with control group 0,05 (± 0,10) vs 0,005 (± 0,02) on the left side and 0,10 (± 0,12) vs. 0.004 (± 0.02) on the right side. Hyperechogenicity of lenticular nuclei were observed in the case of 8 patients (11.2%) within the control group and they were unilateral changes. Substantia nigra hyperechogenicity did not differ between the two groups. We did not find a correlation between the size of the observed changes and dystonia severity or duration of the disease. The only correlation was the association between the width of the third ventricle and age of patients. We suggest that the hyperechogenic changes within the lenticular nuclei are prevalent in patient with primary cervical dystonia and are an important diagnostic clue.