Iniencephaly

About: Iniencephaly is a research topic. Over the lifetime, 141 publications have been published within this topic receiving 1651 citations.

Spina Bifida and Anencephalus in Greater London

Abstract: In order to make comparisons with the findings in a high frequency area, South Wales, with those in a low frequency area, south-east England, a birth frequency and family study was made of all births with neural tube malformations (spina bifida cystica, encephalocele, anencephaly, and iniencephaly) in 32 of the 33 London Boroughs over a 3-year period from 1 April 1965 to 31 March 1968. The births were ascertained through local authority registers, stillbirth and infant death certificates, and hospital records. The frequencies found were 1·54 for spina bifida (including encephalocele) and 1·41 for anencephaly (including iniencephaly). This was less than four tenths of the South Wales frequency. Evidence of an excess of winter births was found for both types of malformation, with a peak for conceptions in February, March, and April. The parents of 870 of the original 1209 index patients were traced and visited for the family survey. The usual social class effect was seen, a deficit of fathers in social class I and II. The birth order distribution of legitimately born patients standardized for maternal age showed only a small excess of firstborn and a deficit rather than an excess of lateborn. For maternal age, however, standardized for birth order, there was an excess of patients born to mothers under 20 and over 35 years of age. The whole family study sample showed a striking excess of patients born to parents from India and Pakistan compared to parents born in the West Indies in relation to households of immigrant parents in the 1966 sample Census. A small sample of 164 patients with matched controls had more parents born in Ireland and India and Pakistan and fewer born in south-east England and the West Indies than the controls. The proportions of sibs affected with spina bifida and anencephaly were 3·42% for spina bifida index patients and 5·44% for anencephaly. For patients born after the index patient the proportions were 5·17 and 4·17%, respectively. The overall risk to sibs was lower than that shown in the South Wales survey, but substantially higher relative to the population birth frequency. The risk to sibs was not apparently influenced by father's social class but there was an indication of an effect of mother's father's social class, with a lower risk where mother had grown up in a class I, II, or IIIa home. There was no apparent influence of grandparental birth place. There was no apparent effect of a relative affected other than a sib. Among cousins a significant increase over the population birth frequency was seen only in mother's sisters' children. The findings, like those of earlier surveys, suggest a multifactorial aetiology of the neural tube malformations, depending both on genetic predisposition and environmental triggers.

Syndromes with cephaloceles

Abstract: Encephaloceles may occur as isolated malformations or together with other anomalies making up various syndromes or associations. With the possible exception of the aberrant tissue band syndrome and the Meckel syndrome, little attention has been paid to syndromes with encephaloceles as a group. This paper discusses syndromes of known genesis, including the aberrant tissue band syndrome, Chemke syndrome, cryptophthalmos syndrome, dyssegmental dwarfism, frontonasal dysplasia, Knobloch syndrome, Meckel syndrome, pseudo-Meckel syndrome, von Voss syndrome, and warfarin syndrome. Associations include a wide range of anomalies that may occur with encephalocele. Some abnormalities are secondary to encephalocele formation; others represent primary noncontiguous embryonic malformations. Associated anomalies include absent corpus callosum, orofacial clefting, craniostenosis, Dandy-Walker defect, Arnold-Chiari defect, ectrodactyly, hemifacial microsomia, hypothalamic-pituitary dysfunction, Klippel-Feil anomaly, iniencephaly, and myelomeningocele. Finally, several other conditions with encephalocele are discussed. Some may represent true low-frequency associations; others are spurious.

Chromosomal abnormalities in fetuses with open neural tube defects: prenatal identification with ultrasound.

Abstract: Objectives To determine the prevalence of chromosomal abnormalities in fetuses with open neural tube defects (NTD) undergoing prenatal chromosome analysis. The role of prenatal ultrasound in detecting those with an underlying chromosomal abnormality was also investigated. Methods Over a 6-year period, 144 fetuses with open NTD underwent prenatal chromosome analysis between 12 and 37 weeks of gestation, as part of a prospective, multicenter prenatal diagnosis and counseling program in Chile. This population included 66 fetuses with spina bifida, 46 with acrania/anencephaly, 21 with cephalocele and 11 with iniencephaly. A confident prenatal diagnosis was made in 143 fetuses (99%) and confirmed postnatally in all cases. Results An underlying chromosomal abnormality was diagnosed in 10 fetuses (7%), six with spina bifida, three with cephalocele and one with craniorachischisis. The prevalence of chromosomal abnormality varied according to the defect present in the fetus, with a 14% (3/21) prevalence among those with cephalocele, 9% (6/66) among those with spina bifida and 2% (1/57) among those with lethal defects such as acrania, anencephaly or iniencephaly. Karyotype results revealed trisomy 18 in seven cases, trisomy 13 in two and mosaicism for a marker chromosome in one. Prenatal ultrasound before the procedure showed that all chromosomally abnormal fetuses had additional findings. The prevalence of chromosomal abnormality in fetuses with spina bifida and cephalocele was higher when chromosome analysis was performed at or before 24 weeks of gestation in comparison to those performed after 24 weeks (5/31 (16%) vs. 4/56 (7%), respectively). However, this difference did not reach statistical significance, probably due to the small number of cases. Conclusions A significant number of fetuses with open NTD are chromosomally abnormal. Although prenatal chromosome analysis should be considered in all cases, prenatal ultrasound seems effective in identifying those fetuses with an underlying chromosomal abnormality. Copyright © 2004 ISUOG. Published by John Wiley & Sons, Ltd.

Heterogeneity of neural tube defects in Europe: the significance of site of defect and presence of other major anomalies in relation to geographic differences in prevalence.

Abstract: In the period 1980-1987, neural tube defects were two to three times more prevalent in populations covered by EUROCAT registries in the United Kingdom and Ireland (UKI) than in Continental Europe and Malta (CEM). 1864 NTD cases in a total population of 580,000 births in UKI and 455 cases in a population of 380,000 births in CEM were analysed to find if there were differences in the ratio of prevalence rates between UKI and CEM according to site of the defect and association with non-central nervous system (CNS) anomalies. The prevalence rate ratio was high for anencephaly with accompanying spina bifida, iniencephaly, and upper spina bifida, and low for encephalocele, lower spina bifida, and anencephaly without other neural tube defects. There was a greater female excess for anencephaly with accompanying spina bifida, iniencephaly, and upper spina bifida than for other defects in both geographic areas. There was a female excess for encephalocele in UKI but a male excess in CEM. Certain sites (anencephaly with accompanying spina bifida, iniencephaly, and encephalocele) were more likely to have accompanying non-CNS anomalies. The prevalence rate ratio of multiply malformed NTD was in general lower than for isolated NTD but showed the same pattern by site. The prevalence rate ratio was high for multiply malformed anencephaly with accompanying spina bifida, iniencephaly, and upper spina bifida. The sex ratio was similar between isolated and multiply malformed cases when site of the defect is taken into account. It is concluded that the geographic prevalence pattern and sex ratio differ according to site of NTD but do not differ substantially according to whether NTD is isolated or associated with non-CNS anomalies.

The range of neural tube defects in southern India.

Abstract: During a prospective study of 3500 consecutive births from November 1985 to January 1987 at three hospitals, 40 babies were found to have neural tube defects, an extremely high incidence (11.4/1000 births). The defects comprised anencephaly (n = 18), meningomyelocele (n = 11), Arnold-Chiari deformity (n = 3), encephalocele (n = 3), iniencephaly (n = 2), and one each of occipital meningocele, spina bifida occulta, and anencephaly with rachischisis. There were significant differences in incidence between those with consanguineous and nonconsanguineous parents and those whose mothers had previously given birth to malformed infants or who had had miscarriages, and those who had not. Significantly more defects were found among stillborn and low birthweight babies, among girls, and among those whose mothers were aged between 20 and 30 years. Just over a third (14) were breech presentations, and hydramnios was present in 16 (40%).