Selected clinical research involving the central nervous system

This paper updates three clinical research projects involving the central nervous system. Discussions of conditions with encephalocele include several associations: encephalocele/craniostenosis, transsphenoidal encephalocele/hypothalamic-pituitary dysfunction, encephalocele/oculo-auriculo-vertebral spectrum, and encephalocele/frontonasal dysplasia. The relationship between oculo-auriculo-vetebral spectrum with encephalocele and frontonasal dysplasia with epibulbar dermoids and ear tags is also discussed and an explanation for encephalocele formation in the Apert syndrome is provided. Studies of the central nervous system in Apert syndrome indicate that distortion ventriculomegaly is common, but progressive hydrocephalus occurs infrequently. A recurrent pattern of abnormalities was discerned consisting of megalencephaly, gyral abnormalities, and defects of the corpus callosum and limbic structures. Five neuropathologic studies lend further support to this pattern of CNS anomalies in the Apert syndrome. In a study of holoprosencephaly, eight principles governing associated facial dysmorphism were derived. Each diagnostic category was shown to have its own frequency and range of holoprosencephalic faces. Some categories, such as del(13q), have narrow ranges; others, such as trisomy 13 syndrome, have broad ranges. However, no broad diagnostic range is known to include agnathia-holoprosencephaly and other severe forms of facial dysmorphism without agnathia. Absent maxillary incisors and a single maxillary central incisor are extremely common in holoprosencephaly with severe facial dysmorphism and may occur on occasion as a striking microform of holoprosencephaly, most commonly in the autosomal dominant form.     

Potentialities of magnetic resonance imaging in the complex of prenatal radiation diagnosis of fetal malformations

The purpose of the study was to investigate the potentialities of magnetic resonance imaging (MRI) in the complex of prenatal radiation diagnosis of fetal malformations. Twenty-eight female patients with suspected fetal malformations were examined. Ultrasound study was supplemented by MRI according to a specially developed protocol. Various fetal CNS malformations were diagnosed. These included the Arnold-Chiari syndrome, the Dandy-Walker syndrome, occlusive hydrocephaly, lobular holoprosencephaly, porencephaly, diaphragmatic hernias, anomalies of the abdomen and retroperitoneal space, as well as anomalies of facial structures, including median clefts, and dacryocystocele. The use of MRI in the complex prenatal radiation diagnosis makes it possible to visualize fetal malformation more clearly, contributes to the more adequate prediction of the outcome of pregnancy and to the choice of a management policy for a female patient.     

Goldenhar syndrome, anterior encephalocele, and aqueductal stenosis following fetal primidone exposure

Fetal exposure to primidone was associated with Goldenhar syndrome, hemifacial microsomia, tetralogy of Fallot, aqueductal stenosis, and anterior encephalocele in this male infant. No similar cases in anticonvulsant-exposed pregnancies were found on literature review, despite the increased incidence of other anomalies following such exposure. Goldenhar syndrome, especially related to rare central nervous system anomalies, is reviewed. Experimental production of hemifacial microsomia by a folic acid antagonist, triaxene, is mediated via hemorrhage in the fetus. Intraventricular hemorrhage was noted in this infant as were dilated lateral and third ventricles. The hemorrhagic diathesis and/or the folic acid depletion of newborns following fetal anticonvulsant exposure may have been the underlying mechanism.     

Effects of alcohol on the fetus: impact and prevention.

In the spectrum of adverse effects on the fetus or infant associated with maternal drinking during pregnancy the most dramatic is the fetal alcohol syndrome, a pattern of malformation that has been associated with maternal alcohol abuse. Other undesirable outcomes of pregnancy linked to alcohol exposure in utero include growth deficiency, major and minor anomalies, decrements in mental and motor performance, and fetal and perinatal wastage. Alcohol, like other teratogens, does not uniformly affect all those exposed to it. Rather, there seems to be a continuum of effects of alcohol on the fetus with increasingly severe outcomes generally associated with higher intakes of alcohol by the mother. The cost of fetal damage associated with alcohol exposure is very high. A program to decrease the incidence of fetal alcohol effects is therefore imperative. The cornerstone of such a program must be not only education of the public but also careful training of all professionals who provide health care for pregnant women.     

Limb reduction defects in humans associated with prenatal isotretinoin exposure.

Retinoic acid has long been used to induce limb reductions defects in experimental animal studies. No limb malformations, however, have been reported among malformed retinoic acid-exposed human fetuses from case reports or epidemiologic studies. We report a child and a fetus with limb reduction malformations following maternal use of isotretinoin (13-cis-retinoic acid) during the first trimester of pregnancy. The child had a unilaterally absent clavicle and nearly absent scapula, with a short humerus and short, synostotic forearm bones. He also had ventriculomegaly and developmental delay, minor dysmorphic facial features, and a short sternum with a sterno-umbilical raphe. The fetus had a unilaterally absent thumb with normal proximal bony structures. Other findings included hydrocephalus, craniofacial anomalies, thymic agenesis, supracristal ventricular septal defect, single umbilical artery, anal and vaginal atresia, and urethral agenesis with dysplastic, multicystic kidneys. Although the limb malformations were quite dissimilar, a number of anomalies that are frequently found among isotretinoin-exposed fetuses/infants were present in both cases. This increases the probability that retinoic acid caused these limb defects, but a causal association cannot be conclusively drawn on the basis of these two retrospective case reports.     

Perspectives on holoprosencephaly: Part I. Epidemiology, genetics, and syndromology

This paper provides an updated, comprehensive, critical review of the epidemiology, genetics, and syndromic aspects of holoprosencephaly and is divided into four parts. In the first part, epidemiologic aspects are discussed under the following headings: prevalence, temporal trends, socioeconomic status, exposure to environmental teratogens, maternal and paternal ages, pregnancy histories, and birth weights. The second part analyzes the facial phenotypes because the genetic and syndromic aspects of holoprosencephaly cannot be understood without knowledge of facial variability and its meaning. Topics discussed include cyclopia, ethmocephaly, cebocephaly, median cleft lip, and less severe facial dysmorphism. The third section, on genetics, analyzes associated anomalies, chromosomal and non-chromosomal holoprosencephaly, family studies, twin studies, genetics of nonsyndromic holoprosencephaly, and recurrence risks. The final section on syndromology summarizes 48 conditions in which some degree of holoprosencephaly may be a feature.     

A case of methotrexate embryopathy with holoprosencephaly, expanding the phenotype

BACKGROUND: Methotrexate (MTX) embryopathy was described nearly 50 years ago, when this agent began to be used as a cancer treatment and abortifacient. In this report we describe a case with typical features of MTX syndrome together with new features to expand the phenotype. CASE: A 29-year-old woman decided to terminate her unwanted pregnancy because of ill health, as she had conceived soon after her last delivery by cesarian section. At 6 weeks of gestation, she took 2.5 mg of MTX 3 times a day for 7 days. The pregnancy termination failed, and the pregnancy was carried to term. A female infant was delivered who was growth retarded and had characteristic features of MTX embryopathy in addition to holoprosencephaly and other brain malformations, facial hypertrichosis, and long eyelashes-features that have not hitherto been described. CONCLUSIONS: We report the first case of holoprosencephaly in association with MTX exposure during the first 6 weeks of gestation. Physicians and the public should be aware of the effects of MTX on the fetus during pregnancy.     

Craniofacial anomalies of the amniotic band syndrome in serial clinical cases

Amniotic band syndrome has been proposed as a sequela of intrauterine rupture of the amnion, resulting in oligohydramnios and passage of the fetus into the chorionic cavity. Amnion disruption with loss of amniotic fluid, causing fetal compression and localized fetal ischemia, possibly results in a pathogenic mechanism of extremely variable malformations. The prominence of the nasal processes and the adjacent stomodeal orifice facilitates free band attachment and adherence, resulting in a spectrum of similarly oriented facial defects. The authors present six consecutive cases of amniotic band syndrome with cleft lip and palate (facial cleft 3, 5, 7, and 10, isolated or combined) that were associated with other craniofacial anomalies, such as craniosynostosis and hypertelorbitism. They also present limb malformations and discuss the proposed pathogenesis and the surgical challenges in functional and aesthetic restoration.     

Proboscis lateralis: a case report

A lateral proboscis usually occurs in the region of the inner canthus. We present a case of holoprosencephaly accompanied by an oblique facial cleft and an anterior encephalocele in which a proboscis lateralis occurred in a very lateral location.     

Outcome of breech delivery at term.

OBJECTIVE--To compare neonatal mortality and morbidity in term infants presenting by the breech and delivered vaginally or by caesarean section. DESIGN--Population based comparison of outcomes. Data derived from the St Mary''s maternity information system. SETTING--North West Thames Regional Health Authority, 1988-90. SUBJECTS--3447 singleton fetuses presenting by the breech at term. MAIN OUTCOME MEASURES--Intrapartum and neonatal mortality, low Apgar scores, intubation at birth, and admission to special care baby units. RESULTS--After the exclusion of babies with congenital anomalies the incidence of intrapartum and neonatal death associated with vaginal birth was 8/961 (0.83%) compared with 1/2486 (0.03%) in babies born by caesarean section (relative risk 20, 95% confidence interval 2.5 to 163). The numbers of low Apgar scores and neonatal intubation were doubled in babies born vaginally or by emergency caesarean section compared with those delivered by elective operation. CONCLUSIONS--The good neonatal outcome associated with elective caesarean delivery of the term breech fetus may influence the decision of women and their obstetricians about mode of delivery.     

The impairment argument for the immorality of abortion: A reply

In his recent article Perry Hendricks presents what he calls the impairment argument to show that abortion is immoral. To do so, he argues that to give a fetus fetal alcohol syndrome is immoral. Because killing the fetus impairs it more than giving it fetal alcohol syndrome, Hendricks concludes that killing the fetus must also be immoral. Here, I claim that killing a fetus does not impair it in the way that giving it fetal alcohol syndrome does. By examining the reason why giving a fetus this condition is wrong, I conclude that the same reasoning, on common pro‐choice accounts, does not apply to killing the fetus. Accordingly, Hendricks's argument does not succeed in showing abortion is immoral.     

Holoprosencephaly: clinical, anatomic, and molecular dimensions

Holoprosencephaly is addressed under the following headings: alobar, semilobar, and lobar holoprosencephaly; arrhinencephaly; agenesis of the corpus callosum; pituitary abnormalities; hindbrain abnormalities; syntelencephaly; aprosencephaly/atelencephaly; neural tube defects; facial anomalies; median cleft lip; minor facial anomalies; single maxillary central incisor; holoprosencephaly-like phenotype; epidemiology; genetic causes of holoprosencephaly; teratogenic causes of holoprosencephaly; SHH mutations; ZIC2 mutations; SIX3 mutations; TGIF mutations; PTCH mutations; GLI2 mutations; FAST1 mutations; TDGF1 mutations; and DHCR7 mutations.     

Comparative ultrasound and magnetic resonance diagnosis of fetal CNS malformations

The study was undertaken to optimize the diagnosis of fetal CNS and facial malformations, by using a complex of ultrasound (US) and magnetic resonance imaging (MRI) studies. A hundred and forty-four fetuses with suspected CNS and facial malformations were examined. The US study conducted by a specially developed protocol was supplemented by MRI (48 fetuses) also made by a specially developed protocol. Various fetal CNS malformations, such as neural tube defects, congenital endbrain malformations, cystic lesions, tumors, ventricular complex anomalies, defects of the face and eyes, multiple defects, including CNS and facial anomalies, were detected. With MRI, the diagnosis was changed in 33% of cases. The application of a complex of US and MRI studies enhances the efficiency of diagnosis of congenital CNS and facial malformations in the fetus. MRI in the diagnosis of fetal CNS and facial malformations has a number of advantages and should be used if there is some difficulty in establishing a diagnosis when an US study is performed.     

A case of otocephaly with anencephaly and meningomyelocele

A case of otocephaly with anencephaly and meningomyelocele: Otocephaly is a rare lethal syndrome with microstomia, aglossia, agnathia, and synotia as major clinical features due to arrest in development of the first branchial arch. Some associated anomalies may be present as cyclopia, holoprosencephaly, cerebellar hypoplasia, situs inversus, and other visceral anomalies. We describe a case of fetus, spontaneously aborted in the 14th week of gestation with otocephaly complex (agnathia, synotia, microstomia) and associated anencephaly and meningomyelocele.     

Multiple congenital malformations including generalized hypertrichosis with gum hypertrophy in a child exposed to valproic acid in utero

Fetal valproate syndrome results from in utero exposure to valproic acid. It is characterized by a distinctive facial appearence, a cluster of minor and major anomalies, and central nervous system dysfunction. We report on a child exposed prenatally to valproic acid with unusual anomalies. This patient was the first child of young parents. Mother had several generalized seizures one year before this pregnancy, and since than she took valproic acid. Pregnancy was otherwise uneventful. At birth physical examination showed generalized hypertrichosis sparing palms and soles, coarse face, gum hypertrophy, hypotonia, club feet and club hands, two annular constrictions of the right lower leg, and abnormal dermatoglyphics. Skeletal X-rays were normal. Gum hypertrophy and hypertrichosis may be part of a broader pattern of altered morphogenesis in fetus exposed to valproic acid or this patient had two conditions, fetal valproate syndrome and hypertrichosis with gum fibromatosis.     

Morphometric analysis of the craniofacial development of the CD-1 mouse fetus exposed to alcohol on gestational day eight

Fetal alcohol syndrome (FAS) describes a pattern of dysmorphogenesis observed in some offspring of women who consumed alcohol during pregnancy; partial expression of this pattern are fetal alcohol effects (FAE). The purpose of this investigation was to measure selected craniofacial parameters in the CD-1 mouse fetus following exposure to alcohol on gestational day (D) 8. CD-1 mice were mated for 1 hr; D0.0 designated by the presence of a vaginal plug. On D8, 0 hr, and D8, 4 hr, 33 dams were injected intraperitoneally (IP) with 25% (v/v) alcohol in physiological saline solution (0.015 ml/gm maternal body weight). Appropriate controls were maintained. The animals were sacrificed every 12 hr from D12.0 through D17.0. Implantation sites were examined and recorded as live, dead, or resorbed fetuses. All live fetuses were weighed, examined for gross defects, and fixed in Bouin's solution. Twenty-three bilateral parameters were recorded for linear dimensions defining face and cranium. The fetal weights were statistically lower in treated as compared to control fetuses only on D16.0 through D17.0. Statistical analysis of the morphometrics identified five distinct growth patterns in treated mice as compared to controls. The anomalies induced in the CD-1 mouse fetus following exposure to alcohol on D8.0 resembled FAE rather than FAS. Morphometric analysis of the craniofacial region may be an important clinical tool for the quantitative identification of alcohol-related effects in the offspring of women who consumed alcohol while pregnant.     

Prenatal diagnosis of Meckel syndrome

Summary The three main features of Meckel syndrome are encephalocele, polycystic kidneys, and polydactyly. Prenatal diagnosis of a fetus with Meckel syndrome was made in the 16th week of gestation by means of amniotic fluid alpha₁ fetoprotein estimation. The indication for amniocentesis was a previous child with an occipital meningocele and polycystic kidneys. Interpretation of the alpha₁-fetoprotein value (240 g/ml) was difficult due to fetal blood contamination. Prenatal diagnosis is indicated in any pregnancy following the birth of a child with only two major symptoms of Meckel syndrome.     

Even if the fetus is not a person,abortion is immoral: The impairment argument

Much of the debate about the ethics of abortion has centered on whether the fetus is a person. In an attempt to sidestep this complex issue, I argue that, even if the fetus is not a person, abortion is immoral. To arrive at this conclusion, I argue that giving a fetus fetal alcohol syndrome is immoral, and that if this is so, then killing the fetus is immoral. Roughly, this is because killing the fetus impairs it more than giving it fetal alcohol syndrome. Since abortion (in most cases) amounts to killing the fetus, this means that abortion (in most cases) is immoral. I defend the premises of this argument against a plethora of objections, concluding that they either do not work, or commit their proponent to a controversial position.     

Atelencephalic microcephaly in a 21-week human fetus

Atelencephalic microcephaly, a rare and extreme disorder, is known morphologically by only six cases. Derivatives of the telencephalon are absent or dysplastic, while more caudal structures are normal or mildly deformed. A more extensive form, aprosencephaly, involves structures of the diencephalon and may be associated with holoprosencephalic facies. Extracranial anomalies may be present in both atelencephaly and aprosencephaly. We describe the seventh and youngest specimen, a 21-week female with atelencephaly. Maternal and gestational histories were unremarkable; the fetus was obtained by therapeutic abortion following diagnosis of a severe cranial malformation by ultrasound. A small and depressed, but intact, calvarium covered the brain. The forebrain was rounded and showed fused hemispheres, absent gyri, olfactory bulbs, and tracts. Caudal structures were mildly deformed. An oval mass of bone filled much of the middle cranial fossa. By light microscopy, several dysplastic changes were apparent in the forebrain. Ventricles were not present; small round cells resembling those of the germinal matrix were prominent in the forebrain. Pyramidal tracts were absent at all levels. The process responsible for these changes cannot be established with certainty; the changes are, however, in keeping with previous damage, such as that accepted for other encephaloclastic disorders. The insult in atelencephaly presumably occurs after closure of the rostral neuropore; earlier damage, with more widespread consequences, is possible for aprosencephaly. As with other destructive processes, etiology in atelencephaly and aprosencephaly is most likely heterogeneous.     

Prenatal echographic diagnosis of laryngeal atresia as part of a multiple congenital anomalies (MCA) syndrome

Prenatal echographic diagnosis of laryngeal atresia as part of a multiple congenital anomalies (MCA) syndrome: In this report we present the prenatal second trimester echographic diagnosis of laryngeal atresia in a male fetus with multiple associated congenital anomalies: oesophageal atresia, crossed fused ectopy of the right kidney, mild cutaneous syndactyly of fingers III-V and toes II-III, distinct facial appearance and single umbilical artery. Bilateral voluminous echogenic lungs were the major echographic diagnostic sign. The associated multiple congenital anomalies were not diagnostic for a distinct, recognizable multiple malformation syndrome.