Alexander disease is a very rare autosomal dominant leukodystrophy, which are neurological conditions caused by anomalies in the myelin which protects nerve fibers in the brain. The most common type is the infantile form that usually begins during the first 2 years of life. Symptoms include mental and physical developmental delays, followed by the loss of developmental milestones, an abnormal increase in head size and seizures. The juvenile form of Alexander disease has an onset between the ages of 2 and 13 years. These children may have excessive vomiting, difficulty swallowing and speaking, poor coordination, and loss of motor control. Adult-onset forms of Alexander disease are less common. The symptoms sometimes mimic those of Parkinson’s disease or multiple sclerosis, or may present primarily as a psychiatric disorder. According to the National Institute of Neurological Disorders and Stroke, the destruction of white matter is accompanied by the formation of Rosenthal fibers—abnormal clumps of protein that accumulate in astrocytes in the brain. The disease occurs in both males and females, and no ethnic, racial, geographic or cultural/economic differences are seen in its distribution. Alexander disease is a progressive and often fatal disease. Presentation
Delays in development of some physical, psychological and behavioral skills; progressive enlargement of the head (macrocephaly), seizures, spasticity, and in some cases also hydrocephalus, idiopathic intracranial hypertension, and dementia. Cause
Alexander disease is a genetic disorder affecting the midbrain and cerebellum of the central nervous system. It is caused by mutations in the gene for glial fibrillary acidic protein (GFAP) that maps to chromosome 17q21.
Symptoms can appear ten to 30 minutes after ingestion, and include nausea, vomiting, diarrhea, abdominal pain,  tingling or burning lips, gums, tongue, face, neck, arms, legs, and toes. Shortness of breath, dry mouth, a choking feeling, confused or slurred speech, and loss of coordination are also possible. PSP in wild marine mammals
PSP has been implicated as a possible cause of sea otter mortality and morbidity in Alaska, as one of its primary prey items, the butter clam (Saxidomus gigantea) bioaccumulates saxitoxin as a chemical defense mechanism. In addition, ingestion of saxitoxin-containing mackerel has been implicated in the death of humpback whales.Additional cases where PSP was suspected as the cause of death in Mediterranean monk seals (Monachus monachus) in the Mediterranean Sea  have been questioned due to lack of additional testing to rule out other causes of mortality. Detection and treatment
In Vivo, in Vitro, analytical techniques and immunoassays can all be used in order to determine whether saxitoxin is present within shellfish or has been ingested by humans. The most common In Vivo method used is that of mouse bioassays, which provides quantitative and qualitative data regarding the relative toxicity of a suspected PSP infection. An in Vitro method of detection commonly used is that of receptor binding assays which provides similar data to that of mouse bioassays.