Disease relevance of Anencephaly

• Abnormalities in Brca1-deficient embryos were most evident in the neural tube, with 40% of the embryos presenting with varying degrees of spina bifida and anencephaly [1].
• Out of 72 pregnancies correctly classified by the amniotic-fluid alpha-fetoprotein (A.F.P.) test, 2 of 56 without neural-tube defects and all 16 with open neural-tube defects (8 with anencephaly and 8awith open spina bifida) had raised levels of AChE [2].
• There was one birth defect (anencephaly), in a fetus conceived 2.5 months after quinacrine insertions; however, we believe it is not related to the procedure [3].
• Brief maternal hyperthermia (HT) early in pregnancy has been implicated in NTD both in humans and laboratory animals, and anterior NTD including exencephaly and anencephaly are induced frequently when pregnant mice are exposed to HT [4].
• Neural tube defects (open spina bifida, anencephaly, and encephalocele) represent the first congenital malformations to be preventable through public health measures such as supplementation and/or food fortification with folic acid [5].

Psychiatry related information on Anencephaly

• Termination rates after prenatal diagnosis of Down syndrome, spina bifida, anencephaly, and Turner and Klinefelter syndromes: a systematic literature review. European Concerted Action: DADA (Decision-making After the Diagnosis of a fetal Abnormality) [6].
• Fifteen female patients had already married, and out of 13 babies who were born from these patients, there were one with ventricular septal defect, one with mental deficiency, and one with anencephaly, while the rest were entirely normal [7].

High impact information on Anencephaly

• In particular, the AP-2 knockout mice exhibit anencephaly, craniofacial defects and thoraco-abdominoschisis [8].
• Thus, in the case of anencephaly, in which the activity of the adrenal is very low, plasma levels of LDL are 2--3 times higher than in normal fetuses, whereas plasma HDL levels are similar [9].
• Folic acid-preventable spina bifida and anencephaly [10].
• Vitamin B12 and anencephaly [11].
• Disruption of the MacMARCKS gene prevents cranial neural tube closure and results in anencephaly [12].

Chemical compound and disease context of Anencephaly

• In anencephaly, conjugate levels were very low while cortisol levels were relatively normal [13].
• Anencephaly was produced consistently, using vitamin A as the teratogen [14].
• The effects of dexamethasone and anencephaly on newborn serum levels of apolipoprotein A-1 [15].
• In the mouse, exogenous retinoic acid can induce both anterior (anencephaly, exencephaly) and posterior (spina bifida) neural tube defects depending on the developmental stage of treatment [16].
• Increased risks for anencephaly were observed at nitrate levels below the maximum contaminant level among groundwater drinkers only (OR = 2.1, 95% CI: 1.1,4.1 for 5-15 mg/liter; OR = 2.3, 95% CI: 1.1, 4.5 for 16-35 mg/liter; and OR = 6.9, 95% CI: 1.9, 24.9 for 36-67 mg/liter compared with <5 mg/liter) [17].

Biological context of Anencephaly

• The detection of high levels of both maternal serum (MS) alpha-fetoprotein (AFP) and human chorionic gonadotrophin (hCG) during the second trimester led to the ultrasonic demonstration of anencephaly, omphalocele, and partial mole [18].
• After gestational week 15, fetuses with trisomy 21 or 18, anencephaly, or renal disorders were associated with low amniotic fluid PSA levels [19].
• Both parameters were reduced compared with those of normal controls in diaphragmatic hernia, anencephalus, anuric renal anomalies, chondrodystrophies, and osteogenesis inperfecta [20].
• The presence of alpha-MSH in the fetal pars intermedia, the change in the ratio of the alpha-MSH/ACTH cells during the course of development, and the absence of alpha-MSH in anencephaly all support the possibility that human fetal pituitary alpha-MSH is involved in both intrauterine growth and fetal adrenal function and thus also in parturition [21].
• Raised maternal serum AFP values due to multiple pregnancy should not cause unnecessary amniocentesis in the diagnosis of anencephaly or spina bifida if an ultrasound investigation is routinely performed first [22].

Anatomical context of Anencephaly

• In six cases of anencephaly, sections from the margin of the cranial end of defective spinal cords at the aperture of the open lesion were also studied for AFP and GFAP [23].
• In contrast, anencephaly, exencephaly, and defects confined to the sacrum may not be related to altered homocysteine metabolism [24].
• We conclude that the elevated level of low-density lipoprotein cholesterol in cord blood of fetuses with anencephaly is not caused by deficiency of low-density lipoprotein receptors and metabolism in skin fibroblasts but instead by deficiency of low-density lipoprotein receptors and metabolism by atrophic adrenal glands [25].
• These cases presented grossly with microcephaly and missing forebrain, appearing to be cases of aprosencephaly [26].
• Murine exencephaly corresponds to human anencephaly, and provides a model for studying the mechanism of development of the central nervous system [27].

Gene context of Anencephaly

• In contrast, anencephaly, exencephaly, and defects confined to the sacrum included many cases that had both normal MTHFR alleles and normal homocysteine and were not significantly different from controls [24].
• In pregnancies complicated with anencephaly and spina bifida no significant difference was demonstrated for alpha-1-antitrypsin, alpha-1-antichymotrypsin and urokinase [28].
• In a significant proportion (23%) of p53-/- female embryos, the normal process of neural tube closure failed, leading to exencephaly and subsequent anencephaly [29].
• Anencephaly with diaphragmatic hernia in sibs [30].
• Cases were identified by the New York State Congenital Malformations Registry as babies with cleft palate (n = 121), cleft lip with or without cleft palate (n = 197), born in 1983-1984, and anencephalus and spina bifida (n = 224), born in 1983-1986, all to upstate New York residents [31].

Analytical, diagnostic and therapeutic context of Anencephaly

• If the serum AFP level is normal and if ultrasonography excludes anencephaly the risk of spina bifida might be low enough (about 1 per cent) to make diagnostic amniocentesis difficult to justify [32].
• The reliability of amniotic fluid AFP in the early prenatal diagnosis of spina bifida and anencephaly and the possibility of performing assays on samples sent by post from any part of the world are emphasized [33].
• Neurone specific enolase measured by radioimmunoassay is capable of totally discriminating between normal pregnancies and those complicated by anencephaly [34].
• Experimental anencephaly (functional hypophysectomy) of the rhesus fetus results in lowered concentrations of maternal oestradiol and loss of the precise control of gestational length, with 40% of fetuses delivering beyond term [35].

References