Holoprosencefalia lobar en un recién nacido / Lobar Holoprosencephaly in A Newborn Infant

Introducción: La holoprosencefalia es la consecuencia directa de cambios genéticos o ambientales específicos que interrumpen la división de la línea media del prosencéfalo embrionario o prosencéfalo. Estas alteraciones pueden condicionar disímiles alteraciones fenotípicas en los seres humanos. Objetivo: Describir las manifestaciones clínicas de pacientes con holoprosencefalia y la conducta clínica y terapéutica en un neonato. Presentación del caso: Hijo de padres no consanguíneos, madre de 35 años de edad con antecedente de cervicitis y gestorragia en la segunda mitad del embarazo, y antecedentes familiares de diabetes mellitus y cardiopatía. El parto se produjo a término a las 37 semanas, distócico por cesárea secundaria a un hematoma retroplacentario. Se obtuvo un recién nacido del sexo masculino con presentación pelviana, peso de 3380 gramos y Apgar 9/9 al nacer. La cesárea se realizó en el Hospital Materno Sur Mariana Grajales Coello (área urbana) de Santiago de Cuba. En el recién nacido se observaron rasgos dismórficos principalmente cráneo-facial. No precisó reanimación, pero a los pocos minutos comenzó con cuadro de dificultad respiratoria e hiposaturación. Conclusiones: En la holoprosencefalia el diagnóstico posnatal se puede realizar mediante las características fenotípicas, las malformaciones faciales y los estudios neuroimagenológicos como el ultrasonido transfontanelar y la tomografía axial computarizada de cráneo. Los pacientes deben evaluarse y seguirse en la evolución por un equipo multidisciplinario de especialidades como otorrinolaringología, máxilo-facial, neuropediatría, consulta de neurodesarrollo, genética, fisiatría e imagenología(AU)

Introduction: Holoprosencephaly is the direct consequence of specific genetic or environmental changes that disrupt midline division of the embryonic prosencephalon or prosencephalon. These alterations can condition dissimilar phenotypic alterations in humans. Objective: To describe the clinical manifestations of patients with holoprosencephaly and the clinical and therapeutic behavior in a neonate. Case presentation: Child of non-consanguineous parents, 35-year-old mother with a history of cervicitis and gestation bleeding in the second half of pregnancy, and family history of diabetes mellitus and heart disease. Delivery was at term, at 37 weeks, dystocic by cesarean section secondary to a retroplacental hematoma. The result was a male newborn with breech presentation, weight 3380 grams and Apgar 9/9 at birth. The cesarean section was performed at the Hospital Materno Sur Mariana Grajales Coello (urban area) of Santiago de Cuba. Dysmorphic features were observed in the newborn, mainly craniofacial dysmorphic ones. He did not require resuscitation, but a few minutes later he presented respiratory distress and hyposaturation. Conclusions: In holoprosencephaly, postnatal diagnosis can be made by phenotypic features, facial malformations and neuroimaging studies such as transfontanellar ultrasound and cranial computed tomography. Patients should be evaluated and followed in evolution by a multidisciplinary team of specialties such as otorhinolaryngology, maxillofacial, neuropediatrics, neurodevelopmental consultation, genetics, physiatry and imaging(AU)

Síndrome del incisivo central maxilar medio único en neonato / Solitary median maxillary central incisor syndrome in neonates / Síndrome do incisivo central maxilar médio solitário em neonatos

Introducción: el síndrome del incisivo central maxilar medio único (SMMCI) es un trastorno de etiología desconocida, con base genética heterogénea, que se caracteriza por la erupción de un único incisivo central en el maxilar y que se puede relacionar con multitud de patologías y síndromes, entre los que destacan las alteraciones de la línea media, obstrucción nasal congénita, disfunción hipofisaria, talla baja y holoprosencefalia. Caso clínico: neonato mujer con síndrome dismórfico no filiado y obstrucción nasal congénita, que es diagnosticada de SMMCI tras consultar en repetidas ocasiones por cuadros de dificultad respiratoria y problemas para alimentarse. Conclusiones: el conocimiento de este raro síndrome es fundamental para la realización de un diagnóstico precoz por parte del equipo pediátrico y obstétrico, ya que un diagnóstico temprano es posible, mejorando la evaluación prenatal ecográfica, así como el adecuado manejo posnatal multidisciplinar posterior de nuestros pacientes.

Introduction: the Solitary Median Maxillary Central Incisor Syndrome (SMMCI) is a disorder of unknown etiology, with a heterogeneous genetic basis, characterized by the eruption of a single central incisor in the maxilla and that can be linked to various pathologies and syndromes, among which the alterations of the midline, congenital nasal obstruction, pituitary dysfunction, short stature and holoprosencephaly stand out. Clinical case: female newborns with unknown dysmorphic syndrome and congenital nasal obstruction, diagnosed with SMMCI after repeated consultations due to respiratory distress and feeding problems. Conclusions: understanding this rare syndrome is essential for an early diagnosis to be carried out by the pediatric and obstetric team, since it will improve the ultrasound prenatal assessment, as well as the adequate subsequent multidisciplinary postnatal patient management procedures.

Introdução: a síndrome do incisivo central maxilar médio solitário (SICMMS) é uma desordem de etiologia desconhecida, com base genética heterogênea, caracterizada pela erupção de um único incisivo central na maxila e que pode estar relacionada a uma infinidade de patologias e síndromes. onde se destacam alterações da linha média, obstrução nasal congênita, disfunção hipofisária, baixa estatura e holoprosencefalia. Caso clínico: recém-nascida com síndrome dismórfica de origem desconhecida e obstrução nasal congênita, diagnosticada com SICMSS após várias consultas por desconforto respiratório e problemas de alimentação. Conclusões: o conhecimento desta rara síndrome é essencial para que a equipe pediátrica e obstétrica possa fazer um diagnóstico precoce, pois ele pode melhorar a avaliação ultrassonográfica pré-natal, bem como o adequado manejo pós-natal multidisciplinar pós-natal dos pacientes.

Prenatal diagnosis of middle interhemispheric variant of holoprosencephaly: Report of two cases.

Holoprosencephaly ranges in severity based on the degree of anatomic abnormality. Middle interhemispheric variant of holoprosencephaly is a less common and often milder variant that has the characteristic sonographic findings of an absent cavum septum pellucidum and a single fused ventricle. This subtype may be associated with genetic conditions that have not been well-described in the literature. We present two cases of middle interhemispheric variant of holoprosencephaly diagnosed on fetal ultrasound.

Compound heterozygous splicing CDON variants result in isolated ocular coloboma.

Ocular coloboma is caused by failure of optic fissure closure during development and recognized as part of the microphthalmia, anophthalmia, and coloboma (MAC) spectrum. While many genes are known to cause colobomatous microphthalmia, relatively few have been reported in coloboma with normal eye size. Genetic analysis including trio exome sequencing and Sanger sequencing was undertaken in a family with two siblings affected with bilateral coloboma of the iris, retina, and choroid. Pathogenic variants in MAC genes were excluded. Trio analysis identified compound heterozygous donor splice site variants in CDON, a cell-surface receptor known to function in the Sonic Hedgehog pathway, c.928 + 1G > A and c.2650 + 1G > T, in both affected individuals. Heterozygous missense and truncating CDON variants are associated with dominant holoprosencephaly (HPE) with incomplete penetrance and Cdon-/- mice display variable HPE and coloboma. A homozygous nonsense allele of uncertain significance was recently identified in a consanguineous patient with coloboma and a second molecular diagnosis. We report the first compound heterozygous variants in CDON as a cause of isolated coloboma. CDON is the first HPE gene identified to cause recessive coloboma. Given the phenotypic overlap, further examination of HPE genes in coloboma is indicated.

Agenesis of the septum pellucidum: Prenatal diagnosis and outcome.

OBJECTIVE: The purpose of this study is to describe the imaging findings in a group of fetuses with suspected agenesis of the septum pellucidum (ASP) and to evaluate their clinical outcome. METHODS: This is a retrospective multicenter study on a cohort of fetuses diagnosed with suspected ASP, between 2008 and 2017. The records of each patient, including ultrasound (US) and magnetic resonance studies, were reviewed and compared with the postnatal findings. RESULTS: Forty-seven patients were included in the study at a mean gestational age of 26.6 weeks. In 17 patients, the ASP was considered isolated. Fourteen patients delivered live-born, and all 14 are developing normally. Three were lost to follow-up. Twenty-four patients had associated malformations involving the central nervous system (CNS); 13 were delivered (normal development [5], abnormal [6] and no follow-up [2]). Nine patients opted for termination, and two pregnancies were lost to follow-up. Six patients had non-CNS associated findings, two were delivered with normal neurological development and four had a termination. CONCLUSIONS: Isolated ASP is usually associated with a favorable outcome; but in the presence of associated malformations, there is at least a 50% risk of abnormal development. Current imaging techniques can provide an accurate prognosis in cases when ASP appears isolated.

Lobar holoprosencephaly with craniofacial defects in a Friesian calf: A case report.

BACKGROUND: Holoprosencephaly is a forebrain deformity that results from varying degrees of separation failure of cerebral hemispheres. The condition is classified based on the degree of non-separation of the hemispheres which, in turn, determines its severity. Holoprosencephaly is usually accompanied by craniofacial defects whose severity tends to reflect the extent of brain deformities. In humans, holoprosencephaly is one of the commonest congenital brain anomalies but in animals, reported cases are scarce. The condition has multifactorial aetiology that involves interactions between several genetic and environmental factors. CASE PRESENTATION: A 4-day-old female Friesian calf with a deformed face was reported to the Faculty of veterinary medicine and surgery, Egerton University. The calf and the dam were sired by the same bull. On clinical and radiographic examination, the calf had a short snout that curved dorsally with bilateral cleft lip, right-sided cleft jaw and a largely absent primary palate. Anatomopathological examination revealed brain deformities which included ventral fusion of frontal lobes of cerebral hemispheres, large merged lateral ventricles without septum pellucidum and fornix, hypoplastic corpus callosum, high degree of non-separation between diencephalic structures, poorly developed hippocampal formation and hypoplastic olfactory lobe, optic chiasma, and nerve. CONCLUSION: The case was confirmed as lobar holoprosencephaly based on characteristic anatomopathological findings. The aetiology of the defects in the present case could not be determined though they are thought to be either a result of recessive inheritance or exposure to teratogenic steroid alkaloids through materials fed to the dam during early pregnancy.

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.

Holoprosencephaly in Kabuki syndrome.

Kabuki syndrome is a rare, multi-systemic disorder of chromatin regulation due to mutations in either KMT2D or KDM6A that encode a H3K4 methyltransferase and an H3K27 demethylase, respectively. The associated clinical phenotype is a direct result of temporal and spatial changes in gene expression in various tissues including the brain. Although mild to moderate intellectual disability is frequently recognized in individuals with Kabuki syndrome, the identification of brain anomalies, mostly involving the hippocampus and related structures remains an exception. Recently, the first two cases with alobar holoprosencephaly and mutations in KMT2D have been reported in the medical literature. We identified a de novo, pathogenic KMT2D variant (c.6295C > T; p.R2099X) using trio whole-exome sequencing in a 2-year-old female with lobar holoprosencephaly, microcephaly and cranio-facial features of Kabuki syndrome. This report expands the spectrum of brain anomalies associated with Kabuki syndrome underscoring the important role of histone modification for early brain development.

Disorders of Ventral Induction/Spectrum of Holoprosencephaly.

Disorders of the ventral induction give rise to a group of congenital malformations that share in common the failure of the prosencephalon cleavage and subsequent formation of midline structures, presenting with a wide spectrum of severity. This article focuses on the imaging findings of the holoprosencephaly spectrum and septo-optic dysplasia, their epidemiology, embryology, and the common clinical associated anomalies. Knowledge of the imaging features of these disorders is necessary for a correct interpretation of findings and accurate parental counseling. Diagnostic evaluation of patients should include molecular screening and genetic counseling to characterize prognosis and risk of recurrence.

Holoprosencephaly or severe hydrocephalus: T1 sequence tells the story.

Intracranial lipoma is a relatively rare benign lesion. Many are incidental findings; however, some others may present with headache, hydrocephalus or other neurological symptoms; thus, correct diagnosis of this condition is important. These lesions are of high signal intensity on T2-weighted MRI and especially those close to cerebrospinal fluid (CSF) spaces, can easily be overlooked in the background of high signal intensity of CSF. Here, we present a case of tectal lipoma, with subsequent severe hydrocephalus and absence of septum pellucidum which was initially misinterpreted as a form of holoprosencephaly, due to inadequate attention to T1-weighted images.

Case report: a novel mutation in ZIC2 in an infant with microcephaly, holoprosencephaly, and arachnoid cyst.

RATIONALE: Holoprosencephaly (HPE) is a severe congenital brain malformation resulting from failed or incomplete forebrain division in early pregnancy. PATIENT CONCERNS: In this study, we reported a 9-month old infant girl with mild microcephaly, semilobor HPE, and arachnoid cyst. DIAGNOSES: Potential genetic defects were screened directly using trio-case whole exome sequencing (WES) rather than traditional karyotype, microarray, and Sanger sequencing of select genes. OUTCOMES: A previous unpublished de novo missense mutation (c.1069C >G, p.H357D) in the 3rd zinc finger domain (ZFD3) of the ZIC2 gene was identified in the affected individual, but not in the parents. Sanger sequencing using specific primers verified the mutation. Extensive bioinformatics analysis confirmed the pathogenicity of this extremely rare mutation. Phenotype-genotype analysis revealed significant correlation between the 3rd zinc-finger domain with semilobor HPE. LESSONS: These findings expanded the spectrum of the ZIC2 gene mutations and associated clinical manifestations, which is the first identification of a mutated ZIC2 gene in a Han infant girl with mild microcephaly, semilobor HPE, and arachnoid cyst.

Neuropathology of holoprosencephaly.

Holoprosencephaly (HPE) is a primary disorder of neural induction and patterning of the rostral neural tube resulting in noncleavage of the forebrain with failure to form two separate distinct hemispheres. The spectrum of HPE is very broad and encompasses various neuropathological phenotypes of different severity. The recent literature has demonstrated that the phenotypic variability of HPE ranges from aprosencephaly-atelencephaly, at the most severe end, to milder forms such as the "middle interhemispheric variant" of HPE at the less severe end of the spectrum. Between them, different intermediate forms demonstrate a continuum in a wide phenotypic spectrum rather than well-defined categories. Although the term "HPE" suggests a disorder affecting only the prosencephalon, other brain structures are involved, underlining the complexity of the malformation. Because of close spatiotemporal interactions and common signaling pathways contributing to the development of both brain and face, concomitant facial and ocular anomalies are associated with brain malformation. In this review, the characteristic neuropathological features of the various forms of HPE are described as well as their associated brain, face, and ocular malformations, to delineate the different phenotypes.

Incisivo central único de la línea media del maxilar, holoprosencefalia y estenosis congènita del orificio nasal anterior en un recién nacido prematuro: a propósito de un caso / Solitary median maxillary central incisor, holoprosencephaly and congenital nasal pyriform aperture stenosis in a premature infant: case report

El síndrome del incisivo central único de la línea media del maxilar es un trastorno raro que implica anomalías de la línea media, como holoprosencefalia, anomalías de las fosas nasales, fisura palatina, labio leporino, hipotelorismo, microcefalia y panhipopituitarismo. La estenosis congénita del orificio nasal anterior es una causa mortal de dificultad respiratoria neonatal debido al estrechamiento del orificio nasal anterior, y podría confundirse con la atresia de coanas. En este informe, presentamos el caso de un recién nacido con síndrome del incisivo central único de la línea media del maxilar acompañado de otras anomalías, tales como holoprosencefalia, estenosis del orificio nasal anterior, microcefalia y panhipopituitarismo. El cariotipado mostró una deleción heterocigota en el gen SIX3 en la región 2p21, que produjo una forma más grave de holoprosencefalia.

Solitary median maxillary central incisor syndrome is a rare disorder involving midline abnormalities such as holoprosencephaly, nasal cavity anomalies, cleft palate-lip, hypotelorism, microcephaly, and panhypopituitarism. Congenital nasal pyriform aperture stenosis is a lethal cause of neonatal respiratory distress due to narrowing of the pyriform aperture anteriorly and it can be confused with choanal atresia. In this report, we present a newborn infant with solitary median maxillary central incisor syndrome accompanied by other abnormalities including holoprosencephaly, nasal pyriform aperture stenosis, microcephaly and panhypopituitarism. Chromosomal analysis showed heterozygous SIX3 gene deletion at 2p21 region resulting in a more severe form of holoprosencephaly.

Multichannel visual evoked potentials in the assessment of visual pathways in children with marked brain abnormalities.

PURPOSE: To demonstrate how multichannel visual evoked potentials (VEPs) can provide quantitative measures of visual function in children with marked cortical anatomy abnormalities. METHODS: Four children with marked brain pathology (2 holoprosencephaly, 2 giant interhemispheric cysts with hydrocephalus) underwent pattern reversal and flash VEP recordings from 16 equally distributed electrodes. Voltage maps of the major VEP components were constructed, and their distributions were compared to the magnetic resonance imaging (MRI) findings. RESULTS: No reproducible responses were evident in 1 case, and responses were present, but, as expected based on the MRI finding, not over the occipital electrodes in 3 cases. Thus, the standard clinical VEP electrode placement would not have detected responses. The distribution of responses during monocular testing obtained in 2 cases suggested normal decussation of the visual pathways at the chiasm, and voltage mapping indicated which part of the abnormally positioned brain tissue is functional visual cortex. CONCLUSIONS: In children with markedly abnormal brain anatomy, multichannel VEP recordings can provide quantifiable measures of visual pathway function detected in atypical locations. VEPs provide a quantifiable measure of visual function that could be used to assist in determining visual acuity levels, and offered a baseline for monitoring in the context of raised intracranial pressure. These recordings were also able to identify functional anatomical structures that were not apparent on MRI. In a clinical setting, the use of additional recordings from nonstandard electrode placement based on the MRI findings is suggested.

Telencephalic Flexure and Malformations of the Lateral Cerebral (Sylvian) Fissure.

After sagittal division of the prosencephalon at 4.5 weeks of gestation, the early fetal cerebral hemisphere bends or rotates posteroventrally from seven weeks of gestation. The posterior pole of the telencephalon thus becomes not the occipital but the temporal lobe as the telencephalic flexure forms the operculum and finally the lateral cerebral or Sylvian fissure. The ventral part is infolded to become the insula. The frontal and temporal lips of the Sylvian fissure, as well as the insula, all derive from the ventral margin of the primitive telencephalon, hence may be influenced by genetic mutations with a ventrodorsal gradient of expression. The telencephalic flexure also contributes to a shift of the hippocampus from a dorsal to a ventral position, the early rostral pole of the hippocampus becoming caudal and dorsal becoming ventral. The occipital horn is the most recent recess of the lateral ventricle, hence most vulnerable to anatomic variations that affect the calcarine fissure. Many major malformations include lack of telencephalic flexure (holoprosencephaly, extreme micrencephaly) or dysplastic Sylvian fissure (lissencephalies, hemimegalencephaly, schizencephaly). Although fissures and sulci are genetically programmed, mechanical forces of growth and volume expansion are proposed to be mainly extrinsic (including ventricles) for fissures and intrinsic for sulci. In fetal hydrocephalus, the telencephalic flexure is less affected because ventricular dilatation occurs later in gestation. Flexures can be detected prenatally by ultrasound and fetal magnetic resonance imaging and should be described neuropathologically in cerebral malformations.

Second trimester ultrasound markers of fetal aneuploidy.

Although it is widely accepted that the best time to screen for chromosomal abnormalities is the first trimester, ultrasound evaluation of the fetus in the second trimester has also been shown to be useful for this purpose. A multitude of markers of varying strength has been developed over the past 30 years. In addition, the optimal time to diagnose fetal anomalies with confidence is also the mid second trimester. Therefore, performance of obstetrical ultrasound at this point in gestation continues to be an important component of prenatal care.

Importance of fetal MRI in evaluation of craniofacial deformities.

AIM: This retrospective study aims at demonstrating the importance of a correct and detailed early diagnosis of craniomaxillofacial malformations affecting the fetus, which would (1) allow improvement in ultrasonography (US) diagnosis, (2) help in planning the therapeutic-surgical procedure, and (3) improve handling of the pathology by the families. MATERIALS AND METHODS: Between 2008 and 2011, a sample of 28 fetuses was selected, all with an ultrasound diagnosis of cleft lip (cheiloschisis-CL) and cleft lip and palate (palatoschisis-CLP) and craniofacial malformation, whose mothers had all underwent ultrasound diagnostic examinations and nuclear magnetic resonance (MRI). All cases were submitted to US examination between the 12th and 19th week of pregnancy, US-3D examination performed by a specialist radiologist between the 19th and 22nd week, and MRI examination between the 23rd and 33rd week of pregnancy. RESULTS: The MRI confirmed the ultrasound diagnosis of 16/28 cases and added information in 11/28 cases, and in 1 (1/28) case, the MRI denied previous CL-CLP ultrasound diagnosis. Moreover, in this study MRI improved the analysis of the entire morphology of the fetuses in cases when syndromic involvement with the involvement of other organs needs to be determined. CONCLUSIONS: The MRI method in fetal patients allows to obtain more details regarding the CL-CLP studied, allowing the medical-surgical team to plan, before the birth, the type of postnatal assessment and surgery to be performed, thus minimizing the impact on neonatal health and improving quality of life of both the patient and his family.