One of these studies was conducted on Japanese adolescents who reported visual episodic illusions with macropsia and showed that illusions are three times more likely to occur in association with migraine. The illusions were most prevalent among girls between the ages of 16 and 18. It is unlikely that macropsia in Japanese adolescents could be due to epileptic seizure since only 0.3% of Japanese adolescents have epilepsy. No evidence of drugs was found, which eliminates the possibility of the macropsia in the adolescents being drug-induced. It is also unlikely for macropsia in adolescent children to be associated with a serious disease. It is usually the macropsia or other visual disturbance which precedes the painful migrainous headaches. The episodes of macropsia can occur as part of the aura in a migraine. These episodes are often brief, lasting only a few minutes. Adolescents who are deemed to have multiple distortions per episode, such as slow motion vision and macropsia, are even more likely to be people with migraine. The macropsia episodes associated with migraine are typically equivalent to the duration of the aura, which can range from moments to 15 minutes. Non-migrainous headaches are not known to be associated with episodic illusions. Even in the absence of a migraine, a fever or a hypnogogic state can provoke visual illusions, which one might claim to be macropsia. A person with macropsia may fail to see the connection between the migraine and the macropsia, since the conditions may not elicit symptoms at the same time.
Amish lethal microcephaly is a rare genetic disorder which is characterized by severe microcephaly (small head) from birth, brain hypoplasia (underdeveloped brain), micrognathia (small chin), irritability (at second or third month of age), seizures, problems controlling their body temperature, high levels of alpha-ketogluraic acid in their urine, and less commonly hepatomegaly (large liver). Babies with this condition typically die when they are 6 months old. This disorder was named after the Amish since, in Old Order Amish communities in Pennsylvania, it affects 1 in 500 babies, while 1 in 11 people in the same communities are unaffected carriers of the (recessive) mutation that causes the disorder, it has not been found outside this population.This disorder is caused by mutations in the SLC25A19 gene in chromosome 17q25, it follows an autosomal recessive inheritance pattern


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