Other symptoms may include visual impairment, lack of growth, deafness, blindness, spastic quadriparesis (paralysis), and intellectual deficits.Some infants may have additional abnormalities at birth including seizures, myoclonus (involuntary sudden, rapid jerks), limited thermoregulation abilities, and respiratory problems. Still other infants display no obvious symptoms at birth, going many months without a confirmed diagnosis of hydranencephaly. In some cases severe hydrocephalus, or another cephalic condition, is misdiagnosed. Causes
Hydranencephaly is an extreme form of porencephaly, which is characterized by a cyst or cavity in the cerebral hemispheres.Although the exact cause of hydranencephaly remains undetermined in most cases, the most likely general cause is by vascular insult, such as stroke, injury, intrauterine infections, or traumatic disorders after the first trimester of pregnancy. In a number of cases where intrauterine infection was determined to be the causing factor, most involved toxoplasmosis and viral infections such as enterovirus, adenovirus, parvovirus, cytomegalovirus, herpes simplex, Epstein-Barr, and syncytial viruses. Another cause factor is monochorionic twin pregnancies, involving the death of one twin in the second trimester, which in turn causes vascular exchange to the living twin through placental circulation through twin-to-twin transfusion, causing hydranencephaly in the surviving fetus. One medical journal reports hydranencephaly as an autosomal inherited disorder with an unknown mode of transmission, causing a blockage of the carotid artery where it enters the cranium; this causes obstruction and damage to the cerebral cortex. Genetic
Hydranencephaly is a recessive genetic condition, so both parents must carry the asymptomatic gene and pass it along to their child.
1970: Mary F. Lyon and Susan Hawkes reported that a gene on the X chromosome caused complete insensitivity to androgens in mice. 1981: Barbara Migeon et al. narrowed down the locus of the human androgen receptor gene (or a factor controlling the androgen receptor gene) to somewhere between Xq11 and Xq13. 1988: The human androgen receptor gene is first cloned and partially analyzed by multiple parties. Terry Brown et al. reported the first mutations proven to cause AIS. 1989: Terry Brown et al. reported the exact locus of the AR gene (Xq11-Xq12), and Dennis Lubahn et al. published its intron-exon boundaries. 1994: The androgen receptor gene mutations database was created to provide a comprehensive listing of mutations published in medical journals and conference proceedings. Early terminology
The first descriptions of the effects of AIS appeared in the medical literature as individual case reports or as part of a comprehensive description of intersex physicalities. In 1839, Scottish obstetrician Sir James Young Simpson published one such description in an exhaustive study of intersexuality that has been credited with advancing the medical communitys understanding of the subject. Simpsons system of taxonomy, however, was far from the first; taxonomies or descriptions for the classification of intersexuality were developed by Italian physician and physicist Fortuné Affaitati in 1549, French surgeon Ambroise Paré in 1573, French physician and sexology pioneer Nicolas Venette in 1687 (under the pseudonym Vénitien Salocini), and French zoologist Isidore Geoffroy Saint-Hilaire in 1832.