Introduction
Neural tube defects (NTDs) are a group of congenital malformation with an incidence of 1/1000 live birth worldwide.[1] NTD can be classified into open or closed type. Open NTDs are the most common type of defect which include anencephaly which occurs most predominantly after spina bifida.[2] Anencephaly which results in the absence of cranial vault and subsequent disruption of the cerebral cortex development with severely damaged brain.[3] In anencephaly, forebrain and brain stem are exposed. Forebrain either does not develop or is destroyed leading to the absence of cerebrum and cerebellum. Several factors both genetic and environmental were known to be associated with NTD. Newborns with anencephaly are stillbirth or survive for few hours (30 h). Anencephaly is a lethal malformation, and several associated deformities are known to be associated with NTD. The different malformation which occurred along with anencephaly includes cleft lip, cleft palate, polycystic kidney, spina bifida, simian crease, malrotation of gut, intestinal obstruction, esophageal atresia, diaphragmatic hernia, bladder exstrophy, or renal agenesis. Meckel–Gruber syndrome (MKS) is a lethal ciliopathy characterized by the triad of cystic renal dysplasia, occipital encephalocele, and postaxial polydactyly. The diagnosis of anencephaly can be done either by ultrasound examination or by alpha-fetoprotein test. However, since anencephaly is associated with several anomalies both systemic and nonsystemic, hence pathological examination of abortus is to be done.[4] Only a few studies of this type have been done in southern India; however, in northern India, no study has been done.[5] Hence, the proposed study was undertaken to assess the deformities and systematic anomalies associated with anencephaly and also with histological findings in anencephaly and associated different anomalies.
Methodology
During the study, stillbirth samples of NTDs were collected from the Department of Gynecology and Obstetrics, SS Hospital, Banaras Hindu University. This is a prospective study where all the patients diagnosed with features of NTD by ultrasound or delivered babies with NTD were taken in the study group. During the autopsy, clinical findings, external examination, internal examination, and photography were done along with the histopathology of the specimens to confirm the anomalies at microscopic level using hematoxylin and eosin staining.
Methods of preparation of egg albumin
Egg albumin solution was prepared by mixing equal amount of egg white and glycerin. It was filtered and few crystals of thymol were added to it to prevent the growth of molds in it.
Results
The study shown here determines six cases of anencephaly with different systemic anomalies. During the study, the minimum maternal age having anencephaly baby was 21 and maximum 35 years with a mean age of 26 years. Out of six mothers, four were primigravida (66.66%), one was gravida 2 (16.66%), and the last one was gravida 3 (16.66%). A study shown here determines that out of six cases, four cases were female (80%), one was male (20%), and in one case, sex was undetermined. The gestational age ranged from 14 to 36 weeks with a mean of 23.2 weeks. The head circumference ranged from 10 cm to 26 cm with a mean of 16 cm. On dissection, the entire six fetuses showed different associated systemic anomalies (100%) along with anencephaly. During the study, anencephaly fetuses were suffering from different types of anomalies.
A 24-year-old female presented with 25 weeks 5 days of gestation for routine antenatal examination. There was no history of consanguineous marriage and no history of teratogenic drugs was there. Routine antenatal screening showed a female fetus having features of anencephaly. Case 1 presented with cleft palate in the oral cavity. Ultrasound report showed that supraorbital skull bones and brain tissue is not visualized showing a case of anencephaly and bradycardia of the fetus. Club foot was also seen in both legs. The fetal autopsy was done of the anencephalic subjects after obtaining consent from their parents. All the anencephalic subjects displayed absence of the cerebrum, cerebellum and a poorly developed brain stem. The fetus showed excess hairs on the whole body, i.e., lanugo. There was dilation in the bowel loop leading to intestinal obstruction and the sigmoid colon shifted toward the right side leading to malrotation of the gut. Other visceral organs were normal. A 24-year-old female presented with primigravida for 19 weeks of gestation for routine antenatal examination. She was not on any teratogenic drugs. Routine antenatal screening showed features of anencephaly. On autopsy, the male fetus Case 2 showed a cleft palate with syndactyly in the right hand. X-ray showed the presence of four metatarsals and two phalanges in the right hand. There was dilation in the bowel loop leading to intestinal obstruction and the sigmoid colon shifted towards the right side leading to malrotation of the gut. The fetus has a right lobe of the liver smaller than left lobe. A 35-year-old female presented at 19 weeks 6 days of gestation to the OPD for routine antenatal examination. There was no significant medical and surgical history with no history of consanguineous marriage. Her second daughter died due to jaundice at the age of 23 days. On clinical examination, she was of average nutrition. Ultrasound report showed features of fetal occipital calvarial defect with herniation of occipital lobes leading to anencephaly with postaxial polydactyly and nephromegaly with echogenic medulla which can be correlated with cystic dysplasia of the kidney. Hence, the termination of pregnancy was done after proper counseling and consent and the baby was sent for autopsy. On external examination, the baby was male and showed features of microcephaly with anencephaly. The brain stem was present; however, cerebellum and cerebrum were absent. Oral cavity showed the presence of cleft palate and lobulated tongue. All the four limbs showed postaxial polydactyly with seven fingers in the right and six fingers in the left hand and six fingers in both legs. On autopsy, malrotation of the gut was observed along with bilateral polycystic kidney. The kidney specimen was sent for histopathology for confirmation. On histological observation, multiple cysts were observed in the kidney of fetus. Other visceral organs were normal. The characteristic features of anencephaly, postaxial polydactyly, cleft palate, and polycystic kidney correlated with MKS [Figures 1-3].
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Figure 1: Ventral and dorsal surface of fetus showing encephalocele and polydactyly
Figure 2: (a) Absence of cerebellum and cerebrum, (b) cleft palate, (c) lobulated tongue, (d and e) polydactyly in all four limbs, (f) malrotation of gut
Figure 3: Microphotograph of the kidney showing multiple cysts
A 21-year-old female presented with 14 weeks of gestation and came to a gynecologist for routine antenatal examination. There was no history of consanguineous marriage. She was not on any teratogenic drug. A gravida 2 female fetus Case 4 showed central nervous system anomalies, i.e., spina bifida. USG report showed that the cranium is not opacified. Only facial bones are visualized and brain material is lying in closed sac. On dissection, brain showed the absence of cerebrum and cerebellum with the absence of brain stem. Oral cavity showed the presence of cleft palate. Webbed neck is also observed. The vertebral column shows spina bifida. The only skeletal deformity showed shifting of the spinal cord from the center toward the right side evidence kyphoscoliosis. A bilateral simian crease is observed. Other visceral organs were normal [Table 1]. A 28-year second gravida at 36 weeks of gestation in labor presented in the emergency. Her previous pregnancy was uneventful with a 3-year-old male baby. She delivered a stillborn female fetus. On external examination, there was anencephaly with protruding eyes. Oral cavity showed cleft palate, two teeth. There was presence of simian crease in the right palm along with low-set ears. On autopsy, the forebrain of fetus has thalamus, but cerebrum was absent. The corpus callosum showed the development of only splenium. It was observed that the cerebellum was absent. The medulla oblongata and pons were present. Abnormal rotation of the gut was also observed. Other visceral organs were normal. Again, this fetus showed characteristic features of anencephaly, cleft palate, and polycystic kidney closely correlating with the diagnosis of MKS. Histological examination was done to check multiple cysts in the kidney of fetus. We observed multiple cysts in the kidney of fetus [Figures 4, 5 and Table 1].
Table 1: Different anomalies associated with anencephaly in different cases
Figure 4: (a and b) Ventral and dorsal surface of fetus showing encephalocele. (c) Left lateral showing low set ears, (d) presence of tooth, (e) cleft palate, (f) simian crease, (g) malrotation of gut, (h) polycystic kidney
Figure 5: Gross photograph of cut surface of kidney showing multiple cysts
The different systematic anomalies associated with anencephaly with the number of cases are represented in Table 2.
Table 2: Systemic anomalies associated with anencephaly
Discussion
The incidence of anencephaly varies in different countries. In India, a study of Cherian showed that the incidence rate is 6·57–8·21 per 1000 live births.[6] Other studies showed the incidence rate to be 0.5–6.5 per 1000 live birth.[7–10] A hospital-based study has been done to check the incidence of NTD.[11] A study shows that the incidence of anencephaly varies in different countries with an incidence of 0.54 per 1000 births in Singapore,[12] 12 per 10,000 in Iran, and 10.4 per 10,000 in China. A previous study showed the prevalence of anencephaly to be more in mother of age below 20 and above 35. In our study, the mean age was 26 years with a minimum age of 21 and maximum 35 years; our findings were similar to previous studies reported.[13–16]
In our study, four out of six showed primigravida which is similar to the previous study observed.[17,18] The anencephaly cases were diagnosed at the time when the mother came to SS Hospital for regular check-up. The ultrasound examination showed a defect in fetus and termination of pregnancy was advised. During the study, some cases were spontaneous abortion and some were stillborn with gestational age of 14–36 weeks. Furthermore, there is preponderance of anencephaly more in female fetus (4/6) than males in our study. Some studies showed male preponderance than females.[17] Phenotypic features of anencephaly such as acrania (absence of skull), acephaly (absence of head), and meroanencephaly were present in all cases. Some other features such as low-set ears and protruding eyes were also present in all the cases. A very interesting feature simian crease which is known to be associated with Down’s syndrome was observed in 4 out of 5 (80%) cases. Studies show that anencephaly is associated with anomalies of different systems. In our study out of six cases obtained, two showed spina bifida. Spina bifida is the most common anomaly associated with anencephaly. GIT anomalies were the second most common anomalies associated with anencephaly. In our study, GIT anomalies included cleft palate, lobulated tongue, witched teeth, and intestinal obstruction of megacolon and malrotation of the gut. In our study, we have noticed polycystic kidney in two cases out of five. During the study, we observed two cases having MKS. Studies show the presence of anencephaly which is a defect of the central nervous system (90%), polydactyly (83.3%), and renal dysplasia because the internal structure does not develop properly leading to polycystic kidney (100%).[19–21] MGS shows an autosomal recessive inheritance pattern. In MKS, both male and female are affected equally with a recurrence rate in subsequent pregnancy of 1 in 4 (25%). The survivor rate of infants affected with MKS is very less. Only ten infants have been known to survive after birth with the highest age of 28 months.[2,6,8–10,17] Mortality rate is 100% [Table 3].
Table 3: Comparison of pathological parameters done in a previous study with the present study
Conclusion
Anencephaly is associated with multiple congenital anomalies with observed percentage of 100%. In our study, we conclude that anencephaly is observed in women conceiving at the third decade (20–29 years) of life. It may be concluded from the observations made that Anencephaly showed a female preponderance .The ratio of female to male being 4:1 .Further it was seen that the primigravida showed an increased association with that of anencephaly than multigravida. In our study, we observed a simian crease in 4 out of 5 (80%) cases. Furthermore, there was presence of tooth which was not seen in previous studies. Central nervous system anomalies like spina bifida, GIT anomalies like cleft palate, intestinal obstruction of megacolon, and malrotation of gut were some of the common anomalies which were observed in our study. Club foot, polydactyly, syndactyly, and kyphoscoliosis are the commonly associated anomalies of the skeletal system. Diagnosis of anencephaly can be done by Ultrasonography (USG) examination during early weeks of pregnancy and further pathological examination of abortus should be done. Further to determine the reason associated with anencephaly and other systemic anomalies, genetic studies can be done.
Author contributions
R.S., R., N.K.S. contributed to the conception, design, and writing of the study protocol and the design of search strategies; A., A.K.Y., M.K. located and obtained reports, helped to select and assess cases, conducted the data analysis, and drafted and approved the final paper. All authors contributed to the conception, design, and writing of the study protocol, conducted data analysis, and revised and approved the final paper.
Financial support and sponsorship
Nil.
Conflicts of interest
There are no conflicts of interest.
Acknowledgment
This research was sponsored by Multi-Disciplinary Research Units (MRUs), a grant by ICMR-Department of Health Research.
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