Mitochondrial Encephalopathy: First Portuguese Report of a VARS2 Causative Variant.

INTRODUCTION: Combined oxidative phosphorylation deficiency 20 (COXPD20) is a mitochondrial respiratory chain complex (RC) disorder, caused by disease-causing variants in the VARS2 gene, which encodes a mitochondrial aminoacyl-tRNA synthetase. Here we describe a patient with fatal mitochondrial encephalopathy caused by a homozygous VARS2 gene missense variant. CASE REPORT: We report the case of a girl, the first child of non-consanguineous and healthy parents, born from an uneventful term pregnancy, who presented, in the neonatal period, major hypotonia and microcephaly. At 4 months of age she showed poor eye contact, nystagmus, global psychomotor development delay and failure to thrive, without dysmorphic features. Focal seizures started at 24 months which evolved to a severe epileptic encephalopathy and finally to super refractory status epilepticus, leading to her death at 28 months of age. Etiologic investigation encompassing metabolic and genetic causes failed to disclose a diagnosis. Post-mortem exome sequencing allowed the identification of a pathogenic variant in VARS2 gene in the homozygous state (c.1100C > T, p.Thr367Ile) in the patient, inherited from her heterozygous parents, leading to the diagnosis of COXPD2. CONCLUSION: To the best of our knowledge, this is the fifth case described in the literature of a child with disease-causing variant in VARS2. With this report we expand the knowledge about the phenotype associated with this very rare mitochondrial defect, further emphasizing the use of exome sequencing as a very powerful diagnostic tool.

Long-term mortality analysis in Parkinson's disease treated with deep brain stimulation.

Background. Few data have been published regarding long-term mortality in patients with Parkinson's disease treated with DBS. Methods. This study analyzed long-term mortality rates, causes, and correlates in PD patients treated with DBS. Results. 184 consecutive patients were included; mean follow-up was 50 months. Fifteen deaths occurred (total 8.15%, annual mortality rate 1.94%). Mean age at disease onset and at surgery was 48 ± 2.4 and 63 ± 1.6 years, respectively. Mean disease duration until death was 21 ± 7.8 years. Most deaths related to stroke, myocardial infarction, other vascular/heart disorders, or severe infection; one suicide was recorded. Deceased PD patients were mostly male and had lower motor benefit after DBS, but univariate analysis failed to show significant differences regarding gender and motor benefit. Survival was 99% and 94% at 3 and 5 years. Conclusions. Long-term survival is to be expected in PD patients treated with DBS, possibly higher than previously expected. Death usually supervenes due to vascular events or infection.

Radiologic and neuroradiologic findings in the mucopolysaccharidoses.

The mucopolysaccharidoses (MPS) represent a group of inheritable, clinically heterogeneous lysosomal storage disorders, in which progressive accumulation of glycosaminoglycans (GAGs) can affect organs and tissues all over the body. The current paper discusses the skeletal X-ray and neuroimaging findings in MPS patients, and the imaging techniques that can be used for diagnosing and monitoring abnormalities in the skeleton and central nervous system. Most MPS types show a typical radiologic expression, called dysostosis multiplex, which manifests as malformations of the skeletal system involving bones in the skull, thorax, spine, pelvis, long bones, and hands. Abnormalities of the spine and GAG deposits in the meninges surrounding the spinal cord can result in spinal cord compression, which, if untreated, can lead to compressive myelopathy. Magnetic resonance imaging (MRI) is the most powerful imaging technique for detecting spinal cord compression, but also radiography and computed tomography are useful. GAG deposits in the brain and surrounding tissues can result in brain anomalies, i.e. white matter lesions, brain atrophy, and hydrocephalus, which can be detected using MRI. Skeletal X-ray and neuroimaging findings can play an important role in diagnosis, follow-up, surgical or medical planning, and assessment of treatment response in MPS patients. There is a need for standardized procedures in evaluating and monitoring neurologic complications in these patients.