Angelman syndrome or Angelmans syndrome (AS) is a genetic disorder that mainly affects the nervous system. Symptoms include a small head and a specific facial appearance, severe intellectual disability, developmental disability, limited to no functional speech, balance and movement problems, seizures, and sleep problems. Children usually have a happy personality and have a particular interest in water. The symptoms generally become noticeable by one year of age.Angelman syndrome is due to a lack of function of part of chromosome 15, typically due to a new mutation rather than one inherited from a persons parents. Most of the time, it is due to a deletion or mutation of the UBE3A gene on that chromosome. Occasionally, it is due to inheriting two copies of chromosome 15 from a persons father and none from their mother (paternal uniparental disomy). As the fathers versions are inactivated by a process known as genomic imprinting, no functional version of the gene remains. Diagnosis is based on symptoms and possibly genetic testing.No cure is available. Treatment is generally supportive in nature. Anti-seizure medications are used in those with seizures. Physical therapy and bracing may help with walking. Those affected have a nearly normal life expectancy.AS affects 1 in 12,000 to 20,000 people. Males and females are affected with equal frequency. It is named after British pediatrician Harry Angelman, who first described the syndrome in 1965. An older term, happy puppet syndrome, is generally considered pejorative. Prader–Willi syndrome is a separate condition, caused by a similar loss of the fathers chromosome 15.
The person serum osmolality is measured by freezing point depression and then compared with the predicted osmolality based on the persons measured sodium, glucose, blood urea nitrogen, and any ethanol that may have been ingested. The presence of a large osmolal gap supports a diagnosis of ethylene glycol poisoning. However, a normal osmolar gap does not rule out ethylene glycol exposure because of wide individual variability.The increased osmolal gap is caused by the ethylene glycol itself. As the metabolism of ethylene glycol progresses there will be less ethylene glycol and this will decrease the blood ethylene glycol concentration and the osmolal gap making this test less useful. Additionally, the presence of other alcohols such as ethanol, isopropanol, or methanol or conditions such as alcoholic or diabetic ketoacidosis, lactic acidosis, or kidney failure may also produce an elevated osmolal gap leading to a false diagnosis.Other laboratory abnormalities may suggest poisoning, especially the presence of a metabolic acidosis, particularly if it is characterized by a large anion gap. Large anion gap acidosis is usually present during the initial stage of poisoning. However, acidosis has a large number of differential diagnosis, including poisoning from methanol, salicylates, iron, isoniazid, paracetamol, theophylline, or from conditions such as uremia or diabetic and alcoholic ketoacidosis. The diagnosis of ethylene glycol poisoning should be considered in any people with a severe acidosis. Urine microscopy can reveal needle or envelope-shaped calcium oxalate crystals in the urine which can suggest poisoning; although these crystals may not be present until the late stages of poisoning.