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Ultrasound in Obstetrics & Gynecology :... Feb 2021Most brain abnormalities are present in the first trimester, but only a few are detected so early in gestation. According to current recommendations for first-trimester... (Review)
Review
Most brain abnormalities are present in the first trimester, but only a few are detected so early in gestation. According to current recommendations for first-trimester ultrasound, the fetal head structures that should be visualized are limited to the cranial bones, the midline falx and the choroid-plexus-filled ventricles. Using this basic approach, almost all cases of acrania, alobar holoprosencephaly and cephalocele are detected. However, the majority of other fetal brain abnormalities remain undiagnosed until the midtrimester. Such anomalies would be potentially detectable if the sonographic study were to be extended to include additional anatomic details not currently included in existing guidelines. The aim of this review article is to describe how best to assess the normal fetal brain by first-trimester expert multiplanar neurosonography and to demonstrate the early sonographic findings that characterize some major fetal brain abnormalities. © 2020 International Society of Ultrasound in Obstetrics and Gynecology.
Topics: Encephalocele; Female; Fetus; Holoprosencephaly; Humans; Nervous System Malformations; Pregnancy; Pregnancy Trimester, First; Ultrasonography, Prenatal
PubMed: 33049801
DOI: 10.1002/uog.23149 -
Life (Basel, Switzerland) May 2022This paper describes the contemporary state of knowledge regarding processes that regulate normal development of the embryonic-fetal central nervous system (CNS). The... (Review)
Review
This paper describes the contemporary state of knowledge regarding processes that regulate normal development of the embryonic-fetal central nervous system (CNS). The processes are described according to the developmental timetable: dorsal induction, ventral induction, neurogenesis, neuronal migration, post-migration neuronal development, and cortical organization. We review the current literature on CNS malformations associated with these regulating processes. We specifically address neural tube defects, holoprosencephaly, malformations of cortical development (including microcephaly, megalencephaly, lissencephaly, cobblestone malformations, gray matter heterotopia, and polymicrogyria), disorders of the corpus callosum, and posterior fossa malformations. Fetal ventriculomegaly, which frequently accompanies these disorders, is also reviewed. Each malformation is described with reference to the etiology, genetic causes, prenatal sonographic imaging, associated anomalies, differential diagnosis, complimentary diagnostic studies, clinical interventions, neurodevelopmental outcome, and life quality.
PubMed: 35743840
DOI: 10.3390/life12060809 -
Brain : a Journal of Neurology Sep 2019Marked by incomplete division of the embryonic forebrain, holoprosencephaly is one of the most common human developmental disorders. Despite decades of phenotype-driven...
Marked by incomplete division of the embryonic forebrain, holoprosencephaly is one of the most common human developmental disorders. Despite decades of phenotype-driven research, 80-90% of aneuploidy-negative holoprosencephaly individuals with a probable genetic aetiology do not have a genetic diagnosis. Here we report holoprosencephaly associated with variants in the two X-linked cohesin complex genes, STAG2 and SMC1A, with loss-of-function variants in 10 individuals and a missense variant in one. Additionally, we report four individuals with variants in the cohesin complex genes that are not X-linked, SMC3 and RAD21. Using whole mount in situ hybridization, we show that STAG2 and SMC1A are expressed in the prosencephalic neural folds during primary neurulation in the mouse, consistent with forebrain morphogenesis and holoprosencephaly pathogenesis. Finally, we found that shRNA knockdown of STAG2 and SMC1A causes aberrant expression of HPE-associated genes ZIC2, GLI2, SMAD3 and FGFR1 in human neural stem cells. These findings show the cohesin complex as an important regulator of median forebrain development and X-linked inheritance patterns in holoprosencephaly.
Topics: Adolescent; Animals; Cell Cycle Proteins; Child; Child, Preschool; Chromosomal Proteins, Non-Histone; Female; Holoprosencephaly; Humans; Infant; Infant, Newborn; Male; Mice; Mice, Inbred C57BL; Cohesins
PubMed: 31334757
DOI: 10.1093/brain/awz210 -
Romanian Journal of Morphology and... 2011Holoprosencephaly (HPE) sequence is a rare spectrum of cerebral and facial malformations resulting from incomplete division of the embryonic forebrain into distinct...
Holoprosencephaly (HPE) sequence is a rare spectrum of cerebral and facial malformations resulting from incomplete division of the embryonic forebrain into distinct lateral cerebral hemisphere. Three ranges of increasing severity are described: lobar, semi-lobar and alobar HPE. A subtype of HPE called middle inter-hemispheric variant (MIHF) has been also reported. The etiology is heterogeneous: teratogens, chromosomal abnormalities and single gene mutations can be involved. Holoprosencephaly results in early morbidity and mortality with a reduced survival beyond neonatal period. The disorder is estimated to occur in 1/16,000 live births. This case report presents a male new born diagnosed with holoprosencephaly, accompanied by median cleft palate, absent nasal bones and chromosomal abnormalities.
Topics: Chromosomes, Human; Cleft Palate; Fatal Outcome; Holoprosencephaly; Humans; Karyotyping; Male; Ultrasonography
PubMed: 21655669
DOI: No ID Found -
Orphanet Journal of Rare Diseases Feb 2007Holoprosencephaly (HPE) is a complex brain malformation resulting from incomplete cleavage of the prosencephalon, occurring between the 18th and the 28th day of... (Review)
Review
Holoprosencephaly (HPE) is a complex brain malformation resulting from incomplete cleavage of the prosencephalon, occurring between the 18th and the 28th day of gestation and affecting both the forebrain and the face. It is estimated to occur in 1/16,000 live births and 1/250 conceptuses. Three ranges of increasing severity are described: lobar, semi-lobar and alobar HPE. Another milder subtype of HPE called middle interhemispheric variant (MIHF) or syntelencephaly is also reported. In most of the cases, facial anomalies are observed in HPE, like cyclopia, proboscis, median or bilateral cleft lip/palate in severe forms, ocular hypotelorism or solitary median maxillary central incisor in minor forms. These latter midline defects can occur without the cerebral malformations and then are called microforms. Children with HPE have many medical problems: developmental delay and feeding difficulties, epilepsy, instability of temperature, heart rate and respiration. Endocrine disorders like diabetes insipidus, adrenal hypoplasia, hypogonadism, thyroid hypoplasia and growth hormone deficiency are frequent. To date, seven genes have been positively implicated in HPE: Sonic hedgehog (SHH), ZIC2, SIX3, TGIF, PTCH, GLI2 and TDGF1. A molecular diagnosis can be performed by gene sequencing and allele quantification for the four main genes SHH, ZIC2, SIX3 and TGIF. Major rearrangements of the subtelomeres can also be identified by multiplex ligation-dependent probe amplification (MLPA). Nevertheless, in about 70% of cases, the molecular basis of the disease remains unknown, suggesting the existence of several other candidate genes or environmental factors. Consequently, a "multiple-hit hypothesis" of genetic and/or environmental factors (like maternal diabetes) has been proposed to account for the extreme clinical variability. In a practical approach, prenatal diagnosis is based on ultrasound and magnetic resonance imaging (MRI) rather than on molecular diagnosis. Treatment is symptomatic and supportive, and requires a multidisciplinary management. Child outcome depends on the HPE severity and the medical and neurological complications associated. Severely affected children have a very poor prognosis. Mildly affected children may exhibit few symptoms and may live a normal life.
Topics: Adolescent; Adult; Animals; Child; Child, Preschool; Female; Genetic Counseling; Genetic Testing; Holoprosencephaly; Humans; Infant; Infant, Newborn; Mutation; Pregnancy; Prenatal Diagnosis; Prognosis
PubMed: 17274816
DOI: 10.1186/1750-1172-2-8 -
Revista Paulista de Pediatria : Orgao... 2023To evaluate radiological (gestational and perinatal) and neonatal signs of patients with Patau syndrome and semilobar holoprosencephaly, as well as to report the...
OBJECTIVE
To evaluate radiological (gestational and perinatal) and neonatal signs of patients with Patau syndrome and semilobar holoprosencephaly, as well as to report the association of both pathologies.
CASE DESCRIPTION
This case report is about a female infant, born at term with trisomy of the chromosome 13 and semilobar holoprosencephaly, with thalamic fusion and a single cerebral ventricle, in addition to several other changes that worsened the patient's prognosis.
COMMENTS
Chromosome 13 trisomy is a genetic alteration that leads to the symptoms that determines Patau syndrome. In this syndrome, cardiovascular, urogenital, central nervous system, facial structure and intellectual impairment are common, in addition to problems in limb formation, such as decreased humerus and femur length, polydactyly, hypotelorism and low ear implantation. It is estimated, however, that holoprosencephaly is present in only 24 to 45% of the patients with trisomy 13.
Topics: Infant, Newborn; Pregnancy; Infant; Humans; Female; Holoprosencephaly; Trisomy 13 Syndrome; Trisomy; Polydactyly; Mutation; Chromosomes, Human, Pair 13
PubMed: 36921175
DOI: 10.1590/1984-0462/2023/41/2022027 -
Autopsy & Case Reports 2017
PubMed: 29259929
DOI: 10.4322/acr.2017.033 -
Cells May 2022The cortex is a highly organized structure that develops from the caudal regions of the segmented neural tube. Its spatial organization sets the stage for future... (Review)
Review
The cortex is a highly organized structure that develops from the caudal regions of the segmented neural tube. Its spatial organization sets the stage for future functional arealization. Here, we suggest using a developmental perspective to describe and understand the etiology of common cortical malformations and their manifestation in the human brain.
Topics: Brain; Cerebral Cortex; Humans
PubMed: 35626679
DOI: 10.3390/cells11101642