Psychiatric involvement in adult patients with mitochondrial disease.

Mitochondrial disorders are caused by impairment of the respiratory chain. Psychiatric features often represent part of their clinical spectrum. However, the real incidence of psychiatric disorders in these diseases is unknown. The aim of this study was to evaluate psychiatric involvement in a group of patients with mitochondrial disorders and without already diagnosed mental illness. Twenty-four patients with mitochondrial disorder and without already diagnosed mental diseases have been studied by means of the mini-international neuropsychiatric interview (MINI) and the newcastle mitochondrial diseases adult scale (NMDAS). In patients with mitochondrial disease, psychiatric conditions were far more common than in general Italian population (about 60 vs. 20-25%), and included major depression, agoraphobia and/or panic disorder, generalized anxiety disorder, social anxiety disorder, psychotic syndromes. Psychiatric involvement did not seem to depend on disease progression. Large, multicenter studies are strongly needed to better characterize the natural history of mitochondrial disorders and of their psychiatric involvement. Moreover, the possibility of mitochondrial diseases should be considered in patients with psychiatric diseases. Finally, we encourage psychiatric evaluation as a routinary approach to mitochondrial patients.

Clock T3111C and Per2 C111G SNPs do not influence circadian rhythmicity in healthy Italian population.

A possible relationship between human circadian rhythmicity and polymorphisms in clock genes have been documented. However, these data are controversial, and studies both corroborating and denying them have been reported. T3111C Clock polymorphism had been associated with the human evening preference, however, this association has not been confirmed. Moreover, C111G Per2 polymorphism has been associated with the "morning larks" chronotype in one study, not yet replicated. We have, therefore, performed this study to evaluate whether Per2 C111G and Clock T3111C polymorphisms might influence sleep circadian rhythmicity in a sample of 219 Italian volunteers. A possible interaction between these polymorphisms was also investigated. No differences in Per2 C111G and Clock T3111C allele and genotype frequencies were found, and none of the combined Clock T3111C-Per2 C11G genotypes resulted more frequent in one group compared to the others. Present results do not support a role of these polymorphisms in the circadian phenotypes.

Current and emerging treatment options in the management of Friedreich ataxia.

Friedreich ataxia (FRDA) is the most common autosomal recessive ataxia. Oxidative damage within the mitochondria seems to have a key role in the disease phenotype. Therefore, FRDA treatment options have been mostly directed at antioxidant protection against mitochondrial damage. Available evidence seems to suggest that patients with FRDA should be treated with idebenone, because it is well tolerated and may reduce cardiac hypertrophy and, at higher doses, also improve neurological function, but large controlled clinical trials are still needed. Alternatively, gene-based strategies for the treatment of FRDA may involve the development of small-molecules increasing frataxin gene transcription. Animal and human studies are strongly needed to assess whether any of the potential new treatment strategies, such as iron-chelating therapies or treatment with erythropoietin or histone deacetylase inhibitors and other gene-based strategies, may translate into an effective therapy for this devastating disorder. In this review, we try to provide an answer to some questions related to current and emerging treatment options in the management of FRDA.

Coenzyme Q10 and Neurological Diseases.

Coenzyme Q10 (CoQ10, or ubiquinone) is a small electron carrier of the mitochondrial respiratory chain with antioxidant properties. CoQ10 supplementation has been widely used for mitochondrial disorders. The rationale for using CoQ10 is very powerful when this compound is primary decreased because of defective synthesis. Primary CoQ10 deficiency is a treatable condition, so heightened "clinical awareness" about this diagnosis is essential. CoQ10 and its analogue, idebenone, have also been widely used in the treatment of other neurodegenerative disorders. These compounds could potentially play a therapeutic role in Parkinson's disease, Huntington's disease, amyotrophic lateral sclerosis, Friedreich's ataxia, and other conditions which have been linked to mitochondrial dysfunction. This article reviews the physiological roles of CoQ10, as well as the rationale and the role in clinical practice of CoQ10 supplementation in different neurological diseases, from primary CoQ10 deficiency to neurodegenerative disorders.

Disulfiram neuropathy: two cases of distal axonopathy.

BACKGROUND: Disulfiram may cause a peripheral neuropathy that is considered dose- and duration-of-exposure-related. Axonal degeneration has been described as a pathological hallmark of disulfiram toxicity, but experiments have reported a primary toxic effect of the molecule on Schwann cells and myelin. CASE REPORTS: Case 1: At the end of two months of treatment with disulfiram 250 mg/day, a 31-year-old woman complained of weakness in distal segments of the lower limbs associated with burning dysesthesias, numbness and pain in the soles of the feet and the legs below the knees; bilateral walking steppage, reduction in foot strength, absence of ankle jerk and knee tendon reflexes, and tactile stocking pin-pick and vibratory sensory impairment in the lower limbs below the knee. Disulfiram was discontinued and she recovered partially over three months. Case 2: After one month of treatment with disulfiram 1600 mg/day, a 27-year-old man reported walking impairment, distal lower limb weakness and paresthesias. He had unsteady gait with bilateral steppage and foot drop, absence of ankle jerks and overall sensation impairment below the knee. Disulfiram was discontinued and nine months later there was almost complete recovery of motor deficits, only minor motor weakness in distal leg muscles, and no dysesthesia, sensation deficits or areflexia. In both of them clinical and neurophysiological patterns were indicative of a distal axonopathy. DISCUSSION The mechanisms by which disulfiram cause injury in human nerves are unclear, though may involve carbon disulfide. The discrepancy between experimental and clinical observations is still unexplained. CONCLUSION: We report two cases of disulfiram axonal toxicity and the partial response following discontinuation of the drug.

Autosomal dominant psychiatric disorders and mitochondrial DNA multiple deletions: report of a family.

BACKGROUND: Psychiatric problems, including bipolar affective disorder (BD) and schizophrenia, are common in mitochondrial diseases (MD) and frequently precede the diagnosis of mitochondrial dysfunction. However, they are rarely the only persistent manifestation of a MD and they are usually associated with other neurological or non-neurological features. CASE REPORT: Here, we describe an Italian family with multiple deletions of mtDNA in muscle, in which BD, schizophrenia, and depression recurred over several generations in the absence of other major signs of mitochondrial dysfunction. CONCLUSION: In patients with positive family history of psychiatric problems, the possibility of MD should be kept in mind, even in absence of other canonical features of mitochondrial encephalomyopathies.

Mitochondrial DNA-related disorders.

Mitochondrial diseases are a group of disorders due to a mitochondrial respiratory chain deficiency. They may depend on mitochondrial genome (mtDNA-related disorders) as well as on a nuclear genome defect (nDNA-related disorders). mtDNA-related disorders encompass an increasing number of clinical pictures associated with more than 250 different provisional or confirmed pathogenic changes in mtDNA. Although some clinical syndromes are nosologically defined, most of the cases present with polymorphous phenotypes ranging from pure myopathy to multi-system involvement. Complexity of mitochondrial genetics is in part responsible for the extreme clinical intra- and inter-familial heterogeneity of this group of diseases. In this review, we briefly report an updated classification and overview the main clinical pictures of this class of diseases.

MERRF syndrome without ragged-red fibers: the need for molecular diagnosis.

We report a patient with myoclonic epilepsy who underwent muscle biopsy for suspected mitochondrial disease (myoclonic epilepsy with ragged-red fibers, MERRF). In spite of normal histochemical studies and of the absence of a severe COX deficiency, the molecular analysis showed the common MERRF mutation (A8344G) in the tRNA(Lys) gene on mitochondrial DNA. The case serves to illustrate the importance of pursuing the proposed mitochondrial genetic abnormality, even in patients with normal biopsy findings.

Could mitochondrial haplogroups play a role in sporadic amyotrophic lateral sclerosis?

Mitochondrial impairment has been implicated in the pathogenesis of the amyotrophic lateral sclerosis (ALS). Furthermore, mitochondrial-specific polymorphisms were previously related to other neurodegenerative diseases, such as Parkinson, Friedreich and Alzheimer disease. To investigate if specific genetic polymorphisms within the mitochondrial genome (mtDNA) could act as susceptibility factors and contribute to the clinical expression of sporadic ALS (sALS), we have genotyped predefined European mtDNA haplogroups in 222 Italian patients with sALS and 151 matched controls. Individuals classified as haplogroup I demonstrated a significant decrease in risk of ALS versus individuals carrying the most common haplogroup, H (odds ratio 0.08, 95% confidence interval 0.04-0.4, p < 0.01). Further stratification of the dataset by sex, age and site of onset of disease and survival failed to reach significance for association. Our study provides evidence of the contribution of mitochondrial variation to the risk of ALS development in Caucasians. Further it may help elucidate the mechanism of the mitochondrial dysfunction detectable in ALS, and may be of relevance in development of strategies for the treatment of this disease.