Political terrorism – Violent criminal behaviour designed primarily to generate fear in the community, or substantial segment of it, for political purposes. Non-Political terrorism – Terrorism that is not aimed at political purposes but which exhibits "conscious design to create and maintain a high degree of fear for coercive purposes, but the end is individual or collective gain rather than the achievement of a political objective". Anonymous terrorism – In the two decades prior to 2016–19, "fewer than half" of all terrorist attacks were either "claimed by their perpetrators or convincingly attributed by governments to specific terrorist groups". A number of theories have been advanced as to why this has happened. Quasi-terrorism – The activities incidental to the commission of crimes of violence that are similar in form and method to genuine terrorism but which nevertheless lack its essential ingredient. It is not the main purpose of the quasi-terrorists to induce terror in the immediate victim as in the case of genuine terrorism, but the quasi-terrorist uses the modalities and techniques of the genuine terrorist and produces similar consequences and reaction. For example, the fleeing felon who takes hostages is a quasi-terrorist, whose methods are similar to those of the genuine terrorist but whose purposes are quite different. Limited political terrorism – Genuine political terrorism is characterized by a revolutionary approach; limited political terrorism refers to "acts of terrorism which are committed for ideological or political motives but which are not part of a concerted campaign to capture control of the state".
Because egg cells, but not sperm cells, contribute mitochondria to the developing embryo, only females pass mitochondrial conditions to their children. Mitochondrial disorders can appear in every generation of a family and can affect both males and females, but fathers do not pass mitochondrial traits to their children. In most cases, people with MELAS inherit an altered mitochondrial gene from their mother. Less commonly, the disorder results from a new mutation in a mitochondrial gene and occurs in people with no family history of MELAS. Diagnosis
MRI: Multifocal infarct-like cortical areas in different stages of ischemic evolution, areas that do not conform to any known vascular territory. Initial lesions often occur in the occipital or parietal lobes with eventual involvement of the cerebellum, cerebral cortex, basal ganglia, and thalamus.Lactate levels are often elevated in serum and cerebrospinal fluid. MR spectroscopy may show an elevated lactate peak in affected and even unaffected brain areas. Muscle biopsy shows ragged red fibers. However, genetic evaluation should be done first, which eliminates the need for muscle biopsy in most cases. Diagnosis may be molecular or clinical:
Stroke-like episodes before or after 40 years old
Encephalopathy with seizures or dementia
Blood lactic acidosis* or ragged red fibers on muscle biopsyDue to mitochondrial heteroplasmy, urine and blood testing is preferable to blood alone. PCR and ARMS-PCR are commonly used, reliable, rapid, and cost-effective techniques for the diagnosis of MELAS.Hearing loss and mitochondrial diabetes are common features. Eyes may have a distinctive speckled pigment in the retina, referred to as a maculopathy. Family members may present differently.