The “Double Panda” sign in Leigh disease

Although the “face of the giant panda” sign on magnetic resonance imaging (MRI) is traditionally considered to be characteristic of Wilson disease, it has also been reported in other metabolic disorders. This study describes the characteristic “giant panda” sign on MRI in a child with Leigh disease. The diagnosis was based on the history of neurological regression; examination findings of oculomotor abnormalities, hypotonia, and dystonia; raised serum lactate levels; and characteristic brain stem and basal ganglia signal changes on MRI. The midbrain and pontine tegmental signal changes were consistent with the “face of the giant panda and her cub” sign. In addition to Wilson disease, metabolic disorders such as Leigh disease should also be considered in the differential diagnosis of this rare imaging finding

Clinical and neuroimaging features in two children with mutations in the mitochondrial ND5 gene

Mutations in the mitochondrial-encoded nicotinamide adenine dinucleotide dehydrogenase 5 gene (MT-ND5) has been implicated as an important genetic cause of childhood mitochondrial encephalomyopathies. This study reports the clinical and magnetic resonance imaging findings in two pediatric patients with mutations in the ND5 gene of mitochondrial DNA. The 8-month-old boy with m.13513 G > A mutation presented with infantile basal ganglia stroke syndrome secondary to mineralizing angiopathy. The 7-year-old girl with the m.13514A > G mutation had episodic regression, progressive ataxia, optic atrophy and hyperactivity. Magnetic resonance imaging of the brain showed bilateral symmetrical signal intensity changes in the thalamus, tectal plate and inferior olivary nucleus, which subsided on follow-up image. Both the patients had a stable course. Familiarity with the various phenotypic and magnetic resonance imaging findings and the clinical course in childhood mitochondrial encephalomyopathies may help the physician in targeted metabolic–genetic testing and prognostication

Mitochondrial oxidative phosphorylation disorders in children: Phenotypic, genotypic and biochemical correlations in 85 patients from South India

Mitochondrial Oxidative Phosphorylation (OXPHOS) disorders account for a variety of neuromuscular disorders in children. In this study mitochondrial respiratory chain enzymes were assayed in muscle tissue in a large cohort of children with varied neuromuscular presentations from June 2011 to December 2013. The biochemical enzyme deficiencies were correlated with the phenotypes, magnetic resonance imaging, histopathology and genetic findings to reach a final diagnosis. There were 85 children (mean age: 6.9 ± 4.7 years, M:F:2:1) with respiratory chain enzyme deficiency which included: isolated complex I (n = 50, 60%), multiple complexes (n = 24, 27%), complex IV (n = 8, 9%) and complex III deficiencies (n = 3, 4%). The most common neurological findings were ataxia (59%), hypotonia (59%) and involuntary movements (49%). A known mitochondrial syndrome was diagnosed in 27 (29%) and non-syndromic presentations in 57 (71%). Genetic analysis included complete sequencing of mitochondrial genome, SURF1, POLG1&2. It revealed variations in mitochondrial DNA (n = 8), SURF1 (n = 5) and POLG1 (n = 3). This study, the first of its kind from India, highlights the wide range of clinical and imaging phenotypes and genetic heterogeneity in children with mitochondrial oxidative phosphorylation disorders

Peripheral neuropathy in genetically characterized patients with mitochondrial disorders: a study from South India

Background: There are relatively few studies, which focus on peripheral neuropathy in large cohorts of genetically characterized patients with mitochondrial disorders. This study sought to analyze the pattern of peripheral neuropathy in a cohort of patients with mitochondrial disorders. Methods: The study subjects were derived from a cohort of 52 patients with a genetic diagnosis of mitochondrial disorders seen over a period of 8 years (2006–2013). All patients underwent nerve conduction studies and those patients with abnormalities suggestive of peripheral neuropathy were included in the study. Their phenotypic features, genotype, pattern of peripheral neuropathy and nerve conduction abnormalities were analyzed retrospectively. Results: The study cohort included 18 patients (age range: 18 months–50 years, M:F- 1.2:1).The genotype included mitochondrial DNA point mutations (n = 11), SURF1 mutations (n = 4) and POLG1 (n = 3). Axonal neuropathy was noted in 12 patients (sensori-motor:n = 4; sensory:n = 4; motor:n = 4) and demyelinating neuropathy in 6. Phenotype-genotype correlations revealed predominant axonal neuropathy in mtDNA point mutations and demyelinating neuropathy in SURF1. Patients with POLG related disorders had both sensory ataxic neuropathy and axonal neuropathy. Conclusion: A careful analysis of the family history, clinical presentation, biochemical, histochemical and structural analysis may help to bring out the mitochondrial etiology in patients with peripheral neuropathy and may facilitate targeted gene testing. Presence of demyelinating neuropathy in Leigh's syndrome may suggest underlying SURF1 mutations. Sensory ataxic neuropathy with other mitochondrial signatures should raise the possibility of POLG related disorder