Brains and faces in holoprosencephaly: pre- and postnatal description of 30 cases

The Role of Antenatal Ultrasound Scans in the Early Detection of Alobar Holoprosencephaly: A Case Report

Holoprosencephaly (HPE) is a developmental defect that affects the brain structure due to failure or incomplete division of the prosencephalon at the third week to the fourth week of gestation into cerebral hemispheres. Although the exact cause of HPE remains unclear, it is suspected to result from a combination of genetic and environmental factors. We report a case of alobar HPE. This case was diagnosed on antenatal ultrasonography in a 42-year-old female (Gravida 3, Para 2) with an unremarkable family history and absence of any risk factors. The association of alobar HPE with an atrioventricular canal defect, left-sided clubfoot, and omphalocele, in this case, constitutes a rare fetal morphological presentation. This case highlights the crucial role of regular antenatal ultrasound scans in the early detection of fatal anomalies like alobar HPE.

Holoprosencephaly spectrum: an up-to-date overview of classification, genetics and neuroimaging

Holoprosencephaly (HPE) is a complex forebrain congenital malformation with widely variable outcomes. It represents a disorder of ventral induction, which begins in the fifth gestational week. Its main feature is forebrain cleavage failure, which prevents the brain complete division into right and left hemispheres, the normal development of midline structures, and the deep brain structure. Based on the severity of prosencephalic cleavage failure, three classic forms (lobar, semilobar, and alobar) were described, and subsequently, interhemispheric variant (syntelencephaly) and septopreoptic variants were proposed. This review proposes a practical imaging approach to diagnosing HPE spectrum disorders, allowing an easier recognition and earlier diagnosis, which is essential for prenatal care and adequate parental counseling. In addition, we intend to simplify the understanding of HPE through a didactic discussion, schematic illustrations, and descriptions of each entity's current classification and critical neuroimaging features, as well as the main differential diagnosis of HPE.

Fetal Autopsy: Insights Into the Spectrum of Dysraphisms With Associated Anomalies

Introduction and aim Malformations of the central nervous system (CNS) are one of the most devastating, yet most common congenital anomalies. Congenital CNS anomalies are structural or functional abnormalities of the brain and spinal cord that occur during the intrauterine developmental period and have a high intrauterine mortality. This study aimed to determine the frequency and distribution of neural tube defects (NTDs) in a tertiary care center for a period of 4.5 years. The neural tube defect was analyzed along with the other associated anomalies in the fetus. Its association with maternal risk factors was also analyzed. Materials and methods This retrospective study includes a total of 48 cases of neural tube defects, over a period of 4.5 years from January 2019 to June 2023, retrieved from the archives of the Department of Pathology at Saveetha Medical College. The study population included all fetuses diagnosed with NTDs during the fetal autopsies conducted at Saveetha Medical College during the period of study. The variables studied include maternal age, maternal risk factors, sex of the fetus, other associated anomalies in the fetus, and placental anomalies associated with the NTDs. Results A total of 48 cases of NTDs were included in this study. NTDs were more common among the female fetuses when compared with the male fetuses. The most common NTD observed in our study was anencephaly. The associated anomalies seen with NTDs include dysplastic kidney, unilateral renal agenesis, agenesis of urinary bladder, sacral agenesis, diaphragmatic hernia, bilateral talipes equinovarus deformity in both lower limbs. In the present study, among the placental defects seen in fetuses with NTDs, single umbilical artery was seen in four fetuses with NTDs. Twelve out of the 48 females included in the study did not take folic acid supplements during the antenatal period, and two females had a history of neural tube defects in their previous pregnancies. Conclusion  This study emphasizes that intensive screening and documentation of coexistent abnormalities of NTDs is needed. Either ultrasonography/MRI or fetal autopsy should be conducted in order to exhibit certain diagnoses and to conduct proper prenatal genetic counseling for parents with fetuses having NTDs or having a history of fetuses with NTDs regarding ongoing and future pregnancies.

Phenotypically Discordant Anomalies in Conjoined Twins: Quirks of Nature Governed by Molecular Pathways?

A multitude of additional anomalies can be observed in virtually all types of symmetrical conjoined twins. These concomitant defects can be divided into different dysmorphological patterns. Some of these patterns reveal their etiological origin through their topographical location. The so-called shared anomalies are traceable to embryological adjustments and directly linked to the conjoined-twinning mechanism itself, inherently located within the boundaries of the coalescence area. In contrast, discordant patterns are anomalies present in only one of the twin members, intrinsically distant from the area of union. These dysmorphological entities are much more difficult to place in a developmental perspective, as it is presumed that conjoined twins share identical intra-uterine environments and intra-embryonic molecular and genetic footprints. However, their existence testifies that certain developmental fields and their respective developmental pathways take different routes in members of conjoined twins. This observation remains a poorly understood phenomenon. This article describes 69 cases of external discordant patterns within different types of otherwise symmetrical mono-umbilical conjoined twins and places them in a developmental perspective and a molecular framework. Gaining insights into the phenotypes and underlying (biochemical) mechanisms could potentially pave the way and generate novel etiological visions in the formation of conjoined twins itself.

Efficacy of Systematic Early-Second-Trimester Ultrasound Screening for Facial Anomalies: A Comparison between Prenatal Ultrasound and Postmortem Findings

Second-trimester 2D ultrasound (US) assessment of the fetal anatomy, as proposed by worldwide guidelines, allows detecting the majority of fetal malformation. However, the detection rates of fetal facial anomalies seem to still be low, mostly in cases of isolated facial malformation. The purpose of this research was to assess and analyze the concordance between the antenatal imaging findings from second-trimester US screening and the results of fetal postmortem autopsy. Between January 2010 and January 2020, there were 43 cases where fetuses with prenatal ultrasound diagnosis of a face abnormality, associated or not with a genetic syndrome or chromosomal disorder, following intrauterine death (IUD) or termination of pregnancy (TOP) after the 13 weeks of pregnancy, underwent autopsy in the Pathological Anatomy section of Bari Polyclinic specializing in feto-placental autopsies. The diagnosis of the fetal facial defects at ultrasound was compared with the findings at autopsy in all cases. A very high level of agreement between prenatal ultrasound and autopsy findings was found for facial abnormalities associated with genetic syndromes or numerical abnormality of chromosomes. A lower level of concordance was instead found in isolated facial defects or those associated with other organ anomalies, but not associated with genetic syndrome or numerical chromosome anomaly. A detailed examination of aborted fetuses led to successful quality control of early-second-trimester ultrasound detection of facial anomalies; however, it was less accurate for the isolated ones. It is, thus, reasonable to propose a systematic early-second-trimester prenatal ultrasound screening for facial anatomy by operators specialized in fetal medicine field, using 2D, 3D, and 4D techniques (two-, three-, and four-dimensional ultrasound).

Sonography of fetal holoprosencephaly: a guide to recognize the lesser varieties

BACKGROUND

Alobar holoprosencephaly (HPE) is easily detected during a first-trimester screening examination, conversely, recognizing the lesser varieties may be difficult even in the second trimester.

OBJECTIVES

To describe the imaging findings of a cohort of fetuses with holoprosencephaly (HPE) and to elucidate the appearances of the different anatomical varieties.

MATERIALS AND METHODS

We reviewed medical records and stored images of pregnant women referred to our clinic because of a diagnosis or the suspicion of various forms of HPE. We reported the imaging characteristics, the presence of other associated anomalies, magnetic resonance findings, karyotype and autoptic examinations when available.

RESULTS

Alobar forms show great distortion of normal brain anatomy, with a single ventricle detectable during the first trimester of pregnancy. Extracerebral, face and karyotype abnormalities are often associated. In semilobar and lobar forms the septum pellucidum is typically absent in axial planes, with fused frontal horns, while posterior fossa is often normal. At multiplanar neurosonogram, anomalies involving corpus callosum and cortex development can be detected. Face abnormalities are mild in lobar forms: receding forehead, various degrees of hypotelorism and the presence of a single central maxillary incisor are reported.

CONCLUSIONS

The alobar forms are detectable since the first trimester, with a peculiar single ventricle and extremely frequent extracerebral and karyotype abnormalities. The semilobar and lobar forms are more challenging and the diagnosis is easily missed in a mid-trimester screening exam unless a careful evaluation of both cavum septi pellucidi and frontal horns as well is conducted.

Re-focusing on Agnathia-Otocephaly complex

OBJECTIVES

Agnathia-otocephaly complex is a rare condition characterized by mandibular hypoplasia or agnathia, ear anomalies (melotia/synotia) and microstomia with aglossia. This severe anomaly of the first branchial arch is most often lethal. The estimated incidence is less than 1 in 70.000 births, with etiologies linked to both genetic and teratogenic factors. Most of the cases are sporadic. To date, two genes have been described in humans to be involved in this condition: OTX2 and PRRX1. Nevertheless, the overall proportion of mutated cases is unknown and a significant number of patients remain without molecular diagnosis. Thus, the involvement of other genes than OTX2 and PRRX1 in the agnathia-otocephaly complex is not unlikely. Heterozygous mutations in Cnbp in mice are responsible for mandibular and eye defects mimicking the agnathia-otocephaly complex in humans and appear as a good candidate. Therefore, in this study, we aimed (i) to collect patients presenting with agnathia-otocephaly complex for screening CNBP, in parallel with OTX2 and PRRX1, to check its possible implication in the human phenotype and (ii) to compare our results with the literature data to estimate the proportion of mutated cases after genetic testing.

MATERIALS AND METHODS

In this work, we describe 10 patients suffering from the agnathia-otocephaly complex. All of them benefited from array-CGH and Sanger sequencing of OTX2, PRRX1 and CNBP. A complete review of the literature was made using the Pubmed database to collect all the patients described with a phenotype of agnathia-otocephaly complex during the 20 last years (1998-2019) in order (i) to study etiology (genetic causes, iatrogenic causes…) and (ii), when genetic testing was performed, to study which genes were tested and by which type of technologies.

RESULTS

In our 10 patients' cohort, no point mutation in the three tested genes was detected by Sanger sequencing, while array-CGH has allowed identifying a 107-kb deletion encompassing OTX2 responsible for the agnathia-otocephaly complex phenotype in 1 of them. In 4 of the 70 cases described in the literature, a toxic cause was identified and 22 out the 66 remaining cases benefited from genetic testing. Among those 22 patients, 6 were carrying mutation or deletion in the OTX2 gene and 4 in the PRRX1 gene. Thus, when compiling results from our cohort and the literature, a total of 32 patients benefited from genetic testing, with only 34% (11/32) of patients having a mutation in one of the two known genes, OTX2 or PRRX1.

CONCLUSIONS

From our work and the literature review, only mutations in OTX2 and PRRX1 have been found to date in patients, explaining around one third of the etiologies after genetic testing. Thus, agnathia-otocephaly complex remains unexplained in the majority of the patients, which indicates that other factors might be involved. Although involved in first branchial arch defects, no mutation in the CNBP gene was found in this study. This suggests that mutations in CNBP might not be involved in such phenotype in humans or that, unlike in mice, a compensatory effect might exist in humans. Nevertheless, given that agnathia-otocephaly complex is a rare phenotype, more patients have to be screened for CNBP mutations before we definitively conclude about its potential implication. Therefore, this work presents the current state of knowledge on agnathia-otocephaly complex and underlines the need to expand further the understanding of the genetic bases of this disorder, which remains largely unknown.

CLINICAL RELEVANCE

We made here an update and focus on the clinical and genetic aspects of agnathia-otocephaly complex as well as a more general review of craniofacial development.

Prenatal ultrasound findings of holoprosencephaly spectrum: Unusual associations

OBJECTIVE

The objective of this study is to evaluate the prenatal diagnosis, postnatal characteristics, and the spectrum of associated findings in fetuses with holoprosencephaly (HPE).

METHODS

Fetal neurosonograms, postnatal assessment, and chromosomal analysis were performed in a cohort of 25 fetuses with HPE.

RESULTS

The prevalence of HPE in high-risk pregnancies was 4.4:10 000. The alobar subtype was the most frequently encountered, with 17 cases (68%). Interestingly, among them, four cases (16%) presented with the rare agnathia-otocephaly complex. Chromosomal abnormalities were detected in 11 cases (44%), the most frequent being trisomy 13 in seven cases (five alobar, one semilobar, and one lobar HPE), followed by trisomy 18 in two cases with semilobar HPE. One case of alobar HPE had 45, XX, t(18;22) (q10;q10), -18p karyotyping, and one case of semilobar HPE was associated with triploidy. Facial malformations in HPE spectrum ranged from cyclopia, proboscis, and arrhinia that were associated with the alobar subtype to hypotelorism and median cleft that were frequent among the semilobar and lobar subtypes. Associated neural tube defects were identified in 12% of cases.

CONCLUSION

Our study illustrates the clinical and genetic heterogeneity of HPE and describes different chromosomal abnormalities associated with HPE.

Autopsy Findings of Central Nervous System Anomalies in Intact Fetuses Following Termination of Pregnancy After Prenatal Ultrasound Diagnosis

OBJECTIVES

Central nervous system (CNS) anomalies are the second most frequent category of congenital anomalies after congenital heart defects (CHDs). In this study, the aim was to investigate the distribution of different CNS anomalies with associated anomalies and karyotype in a fetal autopsy population of terminated pregnancies over a 30-year period and to correlate the ultrasonographic diagnoses of CNS anomalies with autopsy findings.

MATERIALS AND METHODS

This study includes 420 intact fetuses with CNS anomalies terminated at gestational ages 11^+ 0 to 33^+ 6 over a 30-year period from 1985 to 2014. An ultrasound (US) examination was performed at the National Centre for Fetal Medicine, St. Olavs Hospital, Trondheim. The autopsies were performed at the Department of Pathology at the same hospital or a collaborating hospital. The anomalies were subcategorized according to the classification by the World Health Organization.

RESULTS

Neural tube defects such as anencephaly (22.4%, 107/477) and spina bifida (22.2%, 106/477) constituted the most common CNS anomalies, followed by congenital hydrocephalus (17.8%, 85/477). In total, the karyotype was abnormal in 21.0% of all termination of pregnancies (TOPs), with trisomy 18 as the most frequent abnormal karyotype. CHDs, skeletal anomalies, and urinary anomalies were the most common associated organ anomalies. Throughout the study period, there was full agreement between US and postmortem findings of CNS anomalies in 96.9% (407/420) of TOPs.

CONCLUSION

In this study of autopsy findings of CNS anomalies in intact fetuses terminated after prenatal US diagnosis, neural tube defects were most common. About half of the fetuses had isolated serious CNS anomalies, while the other half were CNS anomalies associated with structural and/or chromosomal anomalies. The prenatal US diagnoses were in good concordance with autopsy findings. In particular, due to challenges of diagnoses made early in pregnancy, it is necessary to continue the validation practice.

First-Trimester Diagnosis of Agnathia-Otocephaly Complex: A Series of 4 Cases and Review of the Literature

First-trimester ultrasound findings in 4 fetuses with agnathia-otocephaly complex are described. In addition, information from 3 cases reported in the literature was also reviewed, for a total of 7 cases analyzed. All 7 fetuses presented with agnathia and 6 with ventrocaudal displacement of the ears (melotia/synotia). Four fetuses had holoprosencephaly. In 6 cases, the parents opted for termination of pregnancy. The remaining case resulted in premature delivery at 26 weeks due to severe polyhydramnios and early neonatal death. This report highlights the important role of ultrasound in the identification of agnathia-otocephaly complex in the first trimester of pregnancy.

Digynic triploidy in a fetus presenting with semilobar holoprosencephaly

OBJECTIVE

We present digynic triploidy in a fetus with semilobar holoprosencephaly (HPE).

CASE REPORT

A 32-year-old, gravid 1, para 0, woman underwent prenatal ultrasound examination at 12 weeks of gestation, and the ultrasound showed relative macrocephaly, a small non-cystic placenta, and a fetus with absent nasal bone and semilobar HPE. The pregnancy was terminated subsequently, and a 50-g fetus was delivered with a relatively enlarged head and premaxillary agenesis. The placenta was small and non-cystic. Postnatal cytogenetic analysis of the umbilical cord revealed a karyotype of 69, XXX. Postnatal DNA marker analysis using quantitative fluorescent polymerase chain reaction assays and the polymorphic short tandem repeat markers for chromosome 18 and 20 on the placental tissues showed a diallelic pattern with a dosage of 1:2 (paternal allele to maternal allele ratio), indicating a maternal origin of the triploidy.

CONCLUSION

Fetuses with digynic triploidy may present relative macrocephaly, semilobar HPE and a small placenta on prenatal ultrasound.

Alobar holoprosencephaly associated with a rare chromosomal abnormality: Case report and literature review

RATIONALE

Holoprosencephaly is a structural malformation of the brain that results from the complete or incomplete noncleavage of the forebrain of the embryo into 2 hemispheres. We report a severe case of alobar holoprosencephaly diagnosed at 38 weeks, associated with cebocephaly, microcephaly, and craniosynostosis.

PATIENT CONCERN

The main knowledge added by this case is the late ultrasound diagnosis and chromosomal analysis that revealed a very rare abnormality (45X/46,XX/47,XX) with mosaicism at chromosome 18.

DIAGNOSES

Investigation of the mother revealed nothing remarkable from clinical point of view and on laboratory tests. Ultrasonography identified a fetal biometry appropriate for gestational age, except for the head biometry and abdominal circumference, that were appropriate for less than the fifth percentile. Microcephaly, a large midline monoventricle, absent midlinestructures, cleft lip, cebocephaly (hypotelorism, single-nostril nose), ethmocephaly (hypotelorism, interorbital proboscis) and craniosynostosis, were also present. Fetal magnetic resonance imaging of fetus revealed an absent midline structure, a central monoventricle, abnormal corpus calosum, and abnormal gyri.

INTERVENTIONS

A cesarean section at 38 weeks was indicated for fetal bradycardia and a female baby was delivered, with Apgar score 6, weight 2290g. After birth, the diagnosis of the fetus confirmed holoprosencephaly with facial anomalies and demonstrated repeated tonic-clonic seizure, severe respiratory failure, cyanosis, decreased muscle tone, palor, and apnea. Laboratory examination of the newborn revealed acidosis and a prolonged of prothrombin time. The neonate was treated for severe respiratory distress syndrome, with immediate intubation and resuscitation. Vitamin K, fresh frozen plasma, and antibiotics were also administered.

OUTCOMES

After delivery, exitus of the fetus occurred at 3 days and 18hours due to massive pulmonary hemorrhage.

LESSONS

We described a case of alobar holoprosencephaly diagnosed at 38 weeks of gestation and associated with a rare chromosomal abnormality (45X/46,XX/47,XX) with mosaicism at chromosome 18. Emotional implications could have been less severe if the patient underwent regular ultrasonography allowing a diagnosis in the first or early second trimester.

Further evidence for complex inheritance of holoprosencephaly: Lessons learned from pre- and postnatal diagnostic testing in Germany

Holoprosencephaly (HPE) has been defined as a distinct clinical entity with characteristic facial gestalt, which may-or may not-be associated with the true brain malformation observed postmortem in autopsy or in pre- or postnatal imaging. Affected families mainly show autosomal dominant inheritance with markedly reduced penetrance and extremely broad clinical variability even between mutation carriers within the same families. We here present advances in prenatal imaging over the last years, increasing the proportion of individuals with HPE identified prenatally including milder HPE forms and more frequently allowing to detect more severe forms already in early gestation. We report the results of diagnostic genetic testing of 344 unrelated patients for HPE at our lab in Germany since the year 2000, which currently with the application of next generation sequencing (NGS) panel sequencing identifies causal mutations for about 31% (12/38) of unrelated individuals with normal chromosomes when compared to about 15% (46/306) using conventional Sanger sequencing and Multiplex Ligation-dependent Probe Amplification (MLPA). More comprehensive genetic testing by our in house NGS panel sequencing of 10 HPE associated genes (MiSeq™ and NextSeq™500, Illumina, Inc., San Diego, CA) not only allowed to include genes with smaller contribution to the phenotype, but may also unravel additional low frequency or more common genetic variants potentially contributing to the observed large intrafamiliar variability and may ultimately guide our understanding of the individual clinical manifestation of this complex developmental disorder.

Prenatal diagnosis of holoprosencephaly

Holoprosencephaly is a spectrum of congenital defects of forebrain development characterized by incomplete separation of the cerebral hemispheres. In vivo diagnosis can be established with prenatal brain imaging and disease severity correlates with extent of abnormally developed brain tissue. Advances in magnetic resonance imaging (MRI) over the past 25 years and their application to the fetus have enabled diagnosis of holoprosencephaly in utero. Here, we report on the prenatal diagnosis of holoprosencephaly using MRI as part of a diagnostic and management evaluation at a tertiary and quaternary referral center. Using an advanced MRI protocol and a 1.5-Tesla magnet, we show radiographic data diagnostic for the holoprosencephaly spectrum, including alobar, semilobar, lobar, middle interhemispheric, and septopreoptic variant. Accurate prenatal evaluation is important because the severity of imaging findings correlates with postnatal morbidity and mortality in holoprosencephaly. Therefore, this work has implications for the evaluation, diagnosis, management, and genetic counseling that families can receive during a pregnancy.

History and highlights of the teratological collection in the Museum Anatomicum of Leiden University, The Netherlands

The anatomical collection of the Anatomical Museum of Leiden University Medical Center (historically referred to as Museum Anatomicum Academiae Lugduno-Batavae) houses and maintains more than 13,000 unique anatomical, pathological and zoological specimens, and include the oldest teratological specimens of The Netherlands. Throughout four centuries hundreds of teratological specimens were acquired by more than a dozen collectors. Due to the rich history of this vast collection, teratological specimens can be investigated in a unique retrospective sight going back almost four centuries. The entire 19th century collection was described in full detail by Eduard Sandifort (1742-1814) and his son Gerard Sandifort (1779-1848). Efforts were made to re-describe, re-diagnose and re-categorize all present human teratological specimens, and to match them with historical descriptions. In the extant collection a total of 642 human teratological specimens were identified, including exceptional conditions such as faciocranioschisis and conjoined twins discordant for cyclopia, and sirenomelia. Both father and son Sandifort differed in their opinion regarding the causative explanation of congenital anomalies. Whereas, their contemporaries Wouter Van Doeveren (1730-1783) and Andreas Bonn (1738-1817) both presented an interesting view on how congenital anomalies were perceived and explained during the 18th and 19th centuries; the golden age of descriptive teratology. Although this enormous collection is almost 400 years old, it still impresses scientists, (bio)medical students, and laymen visiting and exploring the collections of the Museum Anatomicum in Leiden, The Netherlands.

Prenatal Diagnosis of Isolated Agnathia-Otocephaly: A Case Report and Review of the Literature

Agnathia is a rare disease characterized by the absence of a mandible. Few cases of prenatally diagnosed isolated agnathia have been reported. We present a case report and review of the literature of prenatally diagnosed agnathia. A 38-year-old woman (gravida 0, para 0) was referred to our hospital at 28 weeks and 3 days of gestation for fetal evaluation because of polyhydramnios and suspected facial anomalies. Three-dimensional ultrasonography and MRI indicated agnathia. Premature rupture of the membranes occurred before the parents could reach a decision on the postnatal treatment. We performed emergency cesarean section on the second day of the 33rd week of gestation. The neonate was deemed nonresuscitable and he died of airway obstruction shortly after birth. Because agnathia is associated with very poor prognosis, accurate prenatal diagnosis and detailed counseling should be promptly provided before unexpected delivery to the parents for the determination of postnatal treatment.

Sonographic detection of central nervous system defects in the first trimester of pregnancy

The fetal central nervous system can already be examined in the first trimester of pregnancy. Acrania, alobar holoprosencephaly, cephaloceles, and spina bifida can confidently be diagnosed at that stage and should actively be looked for in every fetus undergoing first-trimester ultrasound. For some other conditions, such as vermian anomalies and agenesis of the corpus callosum, markers have been identified, but the diagnosis can only be confirmed in the second trimester of gestation. For these conditions, data on sensitivity and more importantly specificity and false positives are lacking, and one should therefore be aware not to falsely reassure or scare expecting parents based on first-trimester findings. This review summarizes the current knowledge of first-trimester neurosonography in the normal and abnormal fetus and gives an overview of which diseases can be diagnosed.

Otocephaly: Agnathia- Microstomia-Synotia Syndrome- A Rare Congenital Anomaly

Otocephaly is a rare malformation characterized by the association of agnathia (agenesis of mandible) or mandibular hypoplasia, melotia (anteromedial malposition of ears), microstomia (small mouth), aglossia or microglossia (absent or rudimentary tongue). This rare anomaly of the ventral portion of first brachial arch is a consequence of failure of migration of neural crest cells from hind brain. It leads to the development of maxillary and mandibular prominences and starts to develop at the fourth and fifth week of gestation. We hereby present the autopsy findings of a fetus of 28 weeks gestation abortus having otocephaly without holoprosencephaly.

Semilobar Holoprosencephaly Associated with Multiple Malformations in a Foal

A full-term male foal born in a farm holidays in Maremma (Tuscany, Italy) was euthanized shortly after birth due to the presence of several malformations. The rostral maxilla and the nasal septum were deviated to the right (wry nose), and a severe cervico-thoracic scoliosis and anus atresia were evident. Necropsy revealed ileum atresia and agenesis of the right kidney. The brain showed an incomplete separation of the hemispheres of the rostral third of the forebrain and the olfactory bulbs and tracts were absent (olfactory aplasia). A diagnosis of semilobar holoprosencephaly (HPE) was achieved. This is the first case of semilobar HPE associated with other organ anomalies in horses.

Evaluation and prevalence of major central nervous system malformations: a retrospective study

OBJECTIVE:

Central nervous system (CNS) anomalies are the most common abnormalities of all malformations and can be diagnosed on routine prenatal ultrasonography (US). We aimed to find out fetal CNS anomaly rate in our clinic which is the referral center in the region.

METHODS:

This is a retrospective study of 15000 pregnant women who were scanned for routine obstetric follow-up from January 2012 to July 2013 in our referral center. We diagnosed CNS anomalies in 41 fetuses by using high resolution ultrasound unit with 3.5 MHz transabdominal and 6 MHz transvaginal transducers.

RESULTS:

CNS anomalies included 12 Chiari malformations, 2 Dandy-Walker malformations (DWM), 1 variant of Dandy-Walker syndrome (DWS), 3 iniencephalies, 15 anencephalies, 1 alobar holoprosencephaly, 2 isolated hydrocephalies, 3 hydrocephalies with cerebellar hypoplasia, 1 occipital encephalocele, 1 lumbosacral myelomeningocele accompanied with microcephaly. There were some associated anomalies in the groups that included club-foot deformities in 6 cases, ventricular septal defect (VSD) in 2 cases, polycystic kidney in 2 cases, scoliosis in 1 case, hypoplasic left ventricle in 1 case; alone atrium, single umbilical artery, echogenic focus, hydronephrosis and cleft lip and palate in the same case, and omphalocele in one.

CONCLUSION:

Prognosis and early detection of CNS abnormalities have become an important issue because the most serious complications of major CNS anomalies are disability and getting bedridden and this situation is inevitably related to health economy. On the other hand prognosis of the fetus and family counseling is another important issue. Parents should decide whether to continue their pregnancies or not.

Rare Disease: Lobar Holoprosencephaly With a Median Cleft Lip-Case Report

Holoprosencephaly is a complex malformation of the brain associated with the median facial defects. Variability of the clinical picture is the characteristic of this anomaly. In most cases, the degree of severity of the facial anomaly correlates with the degree of damage to the brain. This article aims to present a rare case of child with a milder form of brain anomaly combined with a severe form of facial anomaly. The article also presents the application of a feeding stimulator to improve the child's quality of life. The anomaly was diagnosed by postnatal sonography of the brain, magnetic resonance imaging of the endocranium, and three-dimensional computed tomography of the craniofacial skeleton.

Biparietal diameter-to-crown-rump length disproportion in first-trimester fetuses with holoprosencephaly

OBJECTIVES

To determine whether the biparietal diameter measurement is altered in first-trimester fetuses with holoprosencephaly.

METHODS

Cases of holoprosencephaly were collected retrospectively from 4 fetal medicine centers, and first-trimester biparietal diameter measurements were reviewed. The diagnosis of holoprosencephaly was established sonographically by the detection of abnormal choroid plexus morphologic characteristics (absent "butterfly" sign) and the identification of a monoventricular cerebral cavity on axial views of the fetal brain. The proportion of fetuses with biparietal diameter measurements below the 5th percentile for crown-rump length was determined.

RESULTS

Among 45 cases of holoprosencephaly reviewed, 43 had information on both biparietal diameter and crown-rump length measurements. The biparietal diameter was below the 5th percentile for crown-rump length in 14 (32.6%) fetuses. Chromosomal analysis was available in 41; no statistically significant difference in biparietal diameter measurement between those with associated chromosomal anomalies and those without anomalies was noted. A supplementary analysis using head circumference measurement showed an even greater proportion of fetuses with holoprosencephaly with measurements below the 5th percentile for crown-rump length (18 of 42 [42.9%]).

CONCLUSIONS

One-third of first-trimester fetuses with a sonographic diagnosis of holoprosencephaly had a biparietal diameter that was smaller than expected for crown-rump length. In this subset of fetuses, the evaluation of intracranial anatomy for signs of holoprosencephaly may be more difficult to perform due to the smaller size of the brain. Therefore, the detection of a biparietal diameter below the 5th percentile as expected from crown-rump length on the first-trimester scan may be a warning sign of holoprosencephaly and should prompt a detailed examination of the intracranial anatomy.

Detection of structural abnormalities in the first trimester using ultrasound

During the past 25 years, embryonic and early fetal ultrasound and diagnosis have increasingly gained attention in pregnancy care. Modern high-frequency ultrasound transducers make it possible to obtain detailed images of the early conceptus and its organs, and thus move part of the anatomy and anomaly scan from the second to the first trimester. Today, detection of embryonic and fetal structural abnormalities in the first trimester has frequently been reported. One has to distinguish between diagnosis during the early period until about 10 weeks when the embryo or early fetus is small and transvaginal ultrasound is applied, and diagnosis during the late period at the nuchal translucency screening, usually carried out using transabdominal ultrasound. Early first-trimester abnormalities are often diagnosed by chance on clinical indications, whereas late first-trimester diagnoses are the result of systematic screening using ultrasound markers.

First trimester screening for holoprosencephaly with choroid plexus morphology ('butterfly' sign) and biparietal diameter

OBJECTIVE

The aim of this study was to determine whether choroid plexus morphology ('butterfly' sign) and biparietal diameter (BPD) are effective sonographic screening tools for holoprosencephaly (HPE) in the first trimester.

METHODS

An axial view of the fetal head was obtained routinely to determine the presence of the 'butterfly' sign in pregnancies presenting for sonographic screening at 11-13 weeks of gestation. The same view was also used to obtain BPD measurements. The definitive diagnosis of HPE was established by the sonographic demonstration of an anterior cerebral monoventricular cavity and thalamic fusion.

RESULTS

During a 9-year study period, 11 068 live fetuses were screened. There were 11 cases of HPE (prevalence 1/1006); all of them were detected by demonstration of an absent 'butterfly' sign with no false-positive cases. The BPD was less than the 5th percentile in 40% of the cases.

CONCLUSIONS

The 'butterfly' sign appears to be a highly sensitive marker for HPE in the first trimester. On the other hand, BPD measurements had a lower sensitivity, implying that microcephaly is not a prominent first-trimester feature in these cases. Incorporation of the 'butterfly' sign into the first trimester anatomy scan is simple and can facilitate the identification of the vast majority of fetuses with HPE in the first trimester.

Holoprosencephaly with multiple anomalies of the craniofacial bones-an autopsy report

Holoprosencephaly (HPE), a disorder which results from a failure of cleavage or the incomplete differentiation of the forebrain structures at various levels or to various degrees, is related to hereditary factors, chromosomal anomalies, cytogenetic abnormalities, and environmental teratogenic factors. We are reporting a case of a multiparous woman who was G3,P3,L2, who delivered a full term foetus with holoprosencephaly and multiple craniofacial anomalies. An autopsy was conducted. Multiple anomalies of the craniofacial bones, which include hypoplasia and synostosis of the frontal bone, anophthalmia, absence of the anterior cranial fossa, hypoplasia of the maxillae, an absent antrum, cleft palate, a central hare lip and arrhinia which includes absence of the nostrils and hypotelorism of the eye placodes, were noted. This case is being reported for its rarity and the available literature was reviewed in this respect.

Prenatal Detection of Fetal Anomalies at the 11- to 13-Week Scan—Part I: Brain, Face and Neck

In the last 20 years, the role of first-trimester ultrasound screening has expanded from individual calculation of the risk of aneuploidy through measurement of the nuchal translucency to a powerful technique to evaluate important aspects of the fetal anatomy. Traditionally, the full anatomy scan for detection of structural anomalies has been performed in the second trimester of pregnancy. However, with the implementation of the first-trimester scan at 11 to 13 weeks of gestation many of the structural anomalies traditionally detected in the second trimester can now be identified earlier in pregnancy. In the first part of this review we discuss the main ultrasound findings that may facilitate the prenatal detection of fetal brain, face and neck abnormalities in the first trimester of pregnancy.

How to cite this article

Sepulveda W, Illescas T, Adiego B, Martinez-Ten P. Prenatal Detection of Fetal Anomalies at the 11- to 13-Week Scan—Part I: Brain, Face and Neck. Donald School J Ultrasound Obstet Gynecol 2013;7(4):359-368.

Early pregnancy scanning for fetal anomalies--the new standard?

For many years, significant efforts have been made toward attempts at early detection of chromosomal and structural malformations, to lower the rate of these defects in newborns. Traditionally, the main ultrasound examination during pregnancy was performed in the second trimester, using transabdominal transducers. The development of high-frequency and high-resolution (5 to 9 MHz; 6 to 12 MHz) transvaginal probes along with substantial improvements in image and signal processing have opened new possibilities for the investigation of early pregnancy. Up until the recent past, many defects were considered unidentifiable early in pregnancy. A large number of those can now be diagnosed already in the first trimester. Early detection of fetal anomalies enables karyotyping by chorionic villus sampling and, in those patients in whom findings are abnormal, simpler procedures for termination of pregnancy may be performed. This may reduce physical and psychological morbidity associated with second-trimester abortions.

Prenatal neurologic anomalies: sonographic diagnosis and treatment

The low prevalence of fetal CNS anomalies results in a restricted level of exposure to, and limited experience for most obstetricians involved in, prenatal ultrasound. Sonographic guidelines for screening the fetal brain in a systematic way may increase the detection rate of fetal CNS anomalies, thus promoting correct referral to tertiary care centers offering patients a multidisciplinary approach to the condition. The aim of this review is to elaborate on the prenatal sonographic diagnosis and outcome of various CNS malformations. Detailed neurosonographic investigation has become available through high-resolution vaginal ultrasound probes and the development of a variety of 3-dimensional (3D) ultrasound modalities, such as ultrasound tomographic imaging. In addition, fetal magnetic resonance imaging is particularly helpful in the detection of gyration and neurulation anomalies, and disorders of the gray and white matter. Isolated mild ventriculomegaly is a rather common finding with good overall outcome. With an increasing diameter of the atria, however, and especially with the presence of associated malformations, long-term neurodevelopmental and behavioral outcome is disturbed in about 15% or more of cases. In view of recent developments in fetal therapy for neural tube defects, there is a clear need for a high level of ultrasound screening, work-up and counseling in tertiary care centers to identify those cases that might benefit from in utero intervention. The failure of prosencephalic midline induction and development results in midline defects ranging from alobar holoprosencephaly to isolated corpus callosum defects. The detection of callosal abnormaties is enhanced by 3D ultrasound, but counseling on neurodevelopmental outcome remains challenging. The Dandy-Walker spectrum includes isolated megacisterna magna, Blake's pouch cyst, hypoplasia of the vermis and Dandy-Walker malformation. Except for complete agenesis of the vermis associated with fourth ventricle cyst formation, data on long-term outcomes for the various conditions is largely lacking. Congenital cytomegalovirus (CMV) results in the highest incidence of children born with, or developing, long-term neurologic conditions. If proof of fetal infection has been delivered, microcephaly, cortical malformations, and intraparenchymal cysts show a strong correlation with poor outcome. Fetuses with CMV-related ultrasound abnormalities might benefit from maternal transplacental treatment. The aneurysm of the vein of Galen, a vascular malformation of the brain, often results in high cardiac output failure. After neonatal arterial embolization, survival is about 50% with normal neurologic development in 36% of cases. Over 50% of intracranial tumors are teratomata, presenting as fast-growing heterogeneous solid-cystic masses with calcifications. Most intracranial hemorrhages are related to the ventricular system, and prognosis is often poor, particularly in cases involving parenchymal and subdural bleeding. Proliferation disorders of the brain are often characterized by microcephaly. Their etiology is heterogeneous and prenatal diagnosis is often made late in gestation.

Cyclopia: an epidemiologic study in a large dataset from the International Clearinghouse of Birth Defects Surveillance and Research

Cyclopia is characterized by the presence of a single eye, with varying degrees of doubling of the intrinsic ocular structures, located in the middle of the face. It is the severest facial expression of the holoprosencephaly (HPE) spectrum. This study describes the prevalence, associated malformations, and maternal characteristics among cases with cyclopia. Data originated in 20 Clearinghouse (ICBDSR) affiliated birth defect surveillance systems, reported according to a single pre-established protocol. A total of 257 infants with cyclopia were identified. Overall prevalence was 1 in 100,000 births (95%CI: 0.89-1.14), with only one program being out of range. Across sites, there was no correlation between cyclopia prevalence and number of births (r = 0.08; P = 0.75) or proportion of elective termination of pregnancy (r = -0.01; P = 0.97). The higher prevalence of cyclopia among older mothers (older than 34) was not statistically significant. The majority of cases were liveborn (122/200; 61%) and females predominated (male/total: 42%). A substantial proportion of cyclopias (31%) were caused by chromosomal anomalies, mainly trisomy 13. Another 31% of the cases of cyclopias were associated with defects not typically related to HPE, with more hydrocephalus, heterotaxia defects, neural tube defects, and preaxial reduction defects than the chromosomal group, suggesting the presence of ciliopathies or other unrecognized syndromes. Cyclopia is a very rare defect without much variability in prevalence by geographic location. The heterogeneous etiology with a high prevalence of chromosomal abnormalities, and female predominance in HPE, were confirmed, but no effect of increased maternal age or association with twinning was observed.

Holoprosencephaly and agnathia spectrum: Presentation of two new patients and review of the literature

Holoprosencephaly (HPE), the most common developmental disorder of the human forebrain, is occasionally associated with the spectrum of agnathia, or virtual absence of the mandible. This condition results in a constellation of structural cerebral and craniofacial abnormalities. Here we present two new patients and review 30 patients from the literature with HPE and variants of agnathia. The majority of these patients are female and have the most severe forms of HPE, with cyclopia present more frequently than is usually observed in cohorts of patients with HPE. Also, many patients have additional clinical findings not typical in patients with classic HPE, particularly situs abnormalities. Recent animal studies suggest that the association of HPE and agnathia may relate to alterations in signaling from forebrain and foregut endoderm organizing centers and subsequent first pharyngeal arch development, although present models are inadequate to explain all of the clinical findings of this enigmatic human syndrome. Further research is required to better elucidate the causal and pathogenic basis of this association.

Prenatal ultrasound diagnosis in 51 cases of holoprosencephaly: craniofacial anatomy, associated malformations, and genetics

OBJECTIVE

To analyze the prenatal ultrasound findings of the craniofacial and extracephalic anatomy, the postnatal pathological findings, and the genetic anomalies in 51 cases of holoprosencephaly (HPE).

MATERIALS AND METHODS

Between 1990 and 2005, a collective of 51 fetuses with tentative ultrasound diagnosis of HPE was recruited at two tertiary referral centers for prenatal ultrasound diagnostics via the Pia Fetal Database (GEMedical Systems, Webling, Germany). Cephalic as well as extracephalic anomalies were investigated, and all cases were subdivided into the subgroups lobar, a lobar, and semilobar HPE. In addition to the ultrasound investigation, 45 fetuses were analyzed for genetic anomalies and 21 fetuses underwent an autopsy.

RESULTS

The average age at diagnosis was 21.9 weeks of gestation. There was a greater number of female fetuses, with an overall ratio of 2.67:1. In 61% of all cases, there was a reduction of growth in comparison with healthy fetuses of the same age. Within the second trimenon, the cephalic anomalies became evident when investigating the diameter of the fetal head (second trimenon: 71%below the fifth percentile; third trimenon: 92% below the fifth percentile). In 82%of the cases, extracephalic anomalies were diagnosed additionally. In 63%, the diagnosis of holoprosencephaly led to a termination of pregnancy. Ten percent of the fetuses were born alive. In 81% of the cases, the diagnosis of HPE was confirmed postnatally. The remaining 19% showed other severe cephalic and extracephalic anomalies. Chromosomal anomalies were detected in 79% of the fetuses, most frequently trisomy 13 (59%).

DISCUSSION

Because of recent advances in the development and improvement of high-resolution ultrasound, early diagnosis of congenital anomalies such as HPE is now possible. In this study, which represents the largest collection of prenatally diagnosed HPE reported in the literature to date, the average age at diagnosis was earlier than in other studies. The ultrasound devices of today provide excellent images of the fetus that allow an exact diagnosis of craniomaxillofacial anomalies as well as extracephalic anomalies. Apart from a very few cases, the diagnosis of HPE is incompatible with life.

Magnetic resonance microscopy defines ethanol-induced brain abnormalities in prenatal mice: effects of acute insult on gestational day 7

BACKGROUND

This magnetic resonance microscopy (MRM)-based report is the second in a series designed to illustrate the spectrum of craniofacial and central nervous system (CNS) dysmorphia resulting from single- and multiple-day maternal ethanol treatment. The study described in this report examined the consequences of ethanol exposure on gestational day (GD) 7 in mice, a time in development when gastrulation and neural plate development begins; corresponding to the mid- to late third week postfertilization in humans. Acute GD 7 ethanol exposure in mice has previously been shown to result in CNS defects consistent with holoprosencephaly (HPE) and craniofacial anomalies typical of those in Fetal Alcohol Syndrome (FAS). MRM has facilitated further definition of the range of GD 7 ethanol-induced defects.

METHODS

C57Bl/6J female mice were intraperitoneally (i.p.) administered vehicle or 2 injections of 2.9 g/kg ethanol on day 7 of pregnancy. Stage-matched control and ethanol-exposed GD 17 fetuses selected for imaging were immersion fixed in a Bouins/Prohance solution. MRM was conducted at either 7.0 Tesla (T) or 9.4 T. Resulting 29 microm isotropic spatial resolution scans were segmented and reconstructed to provide 3D images. Linear and volumetric brain measures, as well as morphological features, were compared for control and ethanol-exposed fetuses. Following MRM, selected specimens were processed for routine histology and light microscopic examination.

RESULTS

Gestational day 7 ethanol exposure resulted in a spectrum of median facial and forebrain deficiencies, as expected. This range of abnormalities falls within the HPE spectrum; a spectrum for which facial dysmorphology is consistent with and typically is predictive of that of the forebrain. In addition, other defects including median facial cleft, cleft palate, micrognathia, pituitary agenesis, and third ventricular dilatation were identified. MRM analyses also revealed cerebral cortical dysplasia/heterotopias resulting from this acute, early insult and facilitated a subsequent focused histological investigation of these defects.

CONCLUSIONS

Individual MRM scans and 3D reconstructions of fetal mouse brains have facilitated demonstration of a broad range of GD 7 ethanol-induced morphological abnormality. These results, including the discovery of cerebral cortical heterotopias, elucidate the teratogenic potential of ethanol insult during the third week of human prenatal development.

Sonoembryology and early prenatal diagnosis of neural anomalies

In the following review, the early development of the central nervous system (CNS), as described by embryologists and anatomists in modern embryological textbooks, is compared with sonoanatomic descriptions from two-dimensional (2D) and three-dimensional (3D) ultrasound studies, week by week in the first trimester. The anatomic descriptions are limited to details that are of interest for the understanding of ultrasound examinations. Further, the detection of main CNS anomalies including spina bifida during the first trimester are presented and discussed. Empty or enlarged brain cavities, or abnormal contours of the head and spine are important diagnostic markers for the detection of CNS anomalies in the very early pregnancy.

Disorders of prosencephalic development

Abnormal ventral induction may result in disorders of formation, cleavage, and midline development of prosencephalic structures. Holoprosencephaly is a developmental field defect of impaired cleavage of prosencephalon. The most widely accepted classification of holoprosencephaly recognizes three major varieties: the alobar, semilobar and lobar types, according to the severity of the malformation. The brain malformations, characterized by the fusion of the cerebral hemisphere along the midline are commonly associated with facial anomalies. Corpus callosum agenesis and septo-optic dysplasia are disorders of prosencephalic midline development, and usually have less severe presentations but still, affected subjects may suffer from neurodevelopmental retardation, and/or endocrinologic and visual disorders. In this article we report an up-to-date of pathogenesis, prenatal sonographic findings, differential diagnosis and prognosis of the aforementioned anomalies.

Lobar holoprosencephaly with a median cleft: case report

Holoprosencephaly is a congenital abnormality of the prosencephalon associated with median facial defects. Its frequency is 1 in 250 pregnancies and 1 in 16,000 live births. The degree of facial deformity usually correlates with the severity of brain malformation. Early mortality is prevalent in severe forms. This report presents a child with lobar holoprosencephaly accompanied by median cleft lip and palate. The treatment and 9 months' follow-up are presented. This unique case shows that holoprosencephaly may present different manifestations of craniofacial malformations, which are not always parallel to the severity of brain abnormalities. Patients with mild to moderate brain abnormalities may survive into childhood and beyond.

Semilobar holoprosencephaly with associated cyclopia and radial aplasia: first trimester diagnosis by means of integrating 2D-3D ultrasound

INTRODUCTION

Holoprosencephaly (HPE) is commonly associated with facial malformations. We present a case of semilobar HPE associated with distal limb defect which was detected at 12 weeks of gestation.

CASE

The fetus had a crown-rump length of 60 mm (12 weeks-4 days), had nuchal translucency thickness of 1.5 mm. Initial two-dimensional (2D) ultrasound revealed the absence of nasal bone, decreased BPD and abnormal profile. Transvaginal 2D ultrasound was effective in the detection of HPE (partially absence of the interhemispheric fissure, fused thalami, the choroid plexuses were not visualized bilateraly: absent 'butterfly' sign), cylopia, absence of the nose and unilateral radial aplasia. Three dimensional (3D) ultrasound provided a better visualization of the associated anomalies. The necropsy result confirmed the sonographic findings: the diagnosis was semilobar HPE, cyclopia, absence of the nose, and the absence of the radius and the thumb in the left arm.

DISCUSSION

Transvaginal 2D sonographic examination is effective in detection of the cases with HPE at first trimester. Fetal morphological study through 3D ultrasound may facilitate the diagnosis of associated anomalies.

First trimester three-dimensional transvaginal imaging of alobar holoprosencephaly associated with proboscis and hypotelorism (ethmocephaly) in a 46,XX fetus

A 19-year-old woman was scanned at 10(+6) weeks gestation by 2D-3D ultrasound. The fetus had a crown-rump length of 40.9 mm, with the cephalic pole occupied by a single cystic cavity measuring 10.6 x 7.7 x 6.8 mm and severe hypotelorism associated with mid-facial hypoplasia. 3D ultrasound confirmed the malformations seen on the 2D scan and enabled the visualization of a proboscis and a low-set right ear. Fetal karyotyping was performed by chorionic villus sampling. Due to major fetal malformations of the fetus, the patient opted for termination of pregnancy. First trimester sonographic diagnosis of holoprosencephaly relies on bilateral visualization of choroid plexuses in what has been called the 'butterfly' sign. Differential diagnosis between holoprosencephaly and hydranencephaly may be difficult in the first trimester of pregnancy. However, midline structures such as falx cerebri, interhemispheric fissure and third ventricle are present in hydranencephaly and are absent in alobar holoprosencephaly, and thalami are never fused in hydranencephaly. 3D ultrasound has demonstrated an increased definition of anatomical abnormalities of malformations, compared with 2D ultrasound, and has proven to be crucial in the decision-making process of parents and in later prenatal counseling, especially in this case where necroscopy examination was refused by the parents. Images obtained by 3D ultrasound gave detailed insight into this ventral midline anomaly, depicting much of the disordered prosencephalic development.