1/12. Mutations in the homeodomain of the human SIX3 gene cause holoprosencephaly.holoprosencephaly (HPE) is a common, severe malformation of the brain that involves separation of the central nervous system into left and right halves. Mild HPE can consist of signs such as a single central incisor, hypotelorism, microcephaly, or other craniofacial findings that can be present with or without associated brain malformations. The aetiology of HPE is extremely heterogeneous, with the proposed participation of a minimum of 12 HPE-associated genetic loci as well as the causal involvement of specific teratogens acting at the earliest stages of neurulation. The HPE2 locus was recently characterized as a 1-Mb interval on human chromosome 2p21 that contained a gene associated with HPE. A minimal critical region was defined by a set of six overlapping deletions and three clustered translocations in HPE patients. We describe here the isolation and characterization of the human homeobox-containing SIX3 gene from the HPE2 minimal critical region (MCR). We show that at least 2 of the HPE-associated translocation breakpoints in 2p21 are less than 200 kb from the 5' end of SIX3. Mutational analysis has identified four different mutations in the homeodomain of SIX3 that are predicted to interfere with transcriptional activation and are associated with HPE. We propose that SIX3 is the HPE2 gene, essential for the development of the anterior neural plate and eye in humans.- - - - - - - - - - ranking = 1keywords = central nervous system, nervous system (Clic here for more details about this article) |
2/12. Unusually prolonged survival and childhood-onset epilepsy in a case of alobar holoprosencephaly.Alobar holoprosencephaly is one of the most severe congenital malformations of the central nervous system. Most affected infants are stillborn or have a very short life-span. The survivors can present with neonatal seizures and/or infantile spasms. We report on an unusually long-lived patient with alobar holoprosencephaly and minor facial dysmorphism, who developed generalized epilepsy during childhood.- - - - - - - - - - ranking = 1keywords = central nervous system, nervous system (Clic here for more details about this article) |
3/12. Inverted duplication of the distal short arm of chromosome 3 associated with lobar holoprosencephaly and lumbosacral meningomyelocele.A fetus with lobar holoprosencephaly and lumbosacral meningomyelocele associated with duplication of the short arm of chromosome 3 is reported. The anomalies were detected on fetal ultrasound at 20 weeks' gestation and the autopsy findings correlated well with the prenatal findings. The fetal karyotype was 46,XY,der(3)del(3)(p26) dup(3)(p26p21.3). The association of holoprosencephaly with duplication 3p is well known, but to the best of our knowledge this is the first reported association of meningomyelocele with 3p duplication. These findings suggest that a gene or genes with a crucial role in central nervous system development are located on the short arm of chromosome 3.- - - - - - - - - - ranking = 1keywords = central nervous system, nervous system (Clic here for more details about this article) |
4/12. Extreme variability of expression of a Sonic Hedgehog mutation: attention difficulties and holoprosencephaly.holoprosencephaly (HPE) is a clinically variable and genetically heterogeneous central nervous system (CNS) malformation. Alobar HPE, which is its most severe form, is associated with a poor prognosis. At the milder end of the HPE spectrum microcephaly, hypotelorism, and single central maxillary incisor may be recognised. Currently, four genes have been identified for this condition. These include Sonic Hedgehog (SHH) on chromosome 7q36, which is thought to be responsible for a significant proportion of autosomal dominant HPE. We report an index case with alobar holoprosencephaly caused by an SHH mutation and six members of his family over two generations with this mutation, with a broad range of clinical presentation, including attention deficit hyperactivity disorder (ADHD). The combination of microcephaly, hypotelorism, subtle midline facial anomalies, and ADHD within a sibship should alert the physician to the possible diagnosis of HPE.- - - - - - - - - - ranking = 1keywords = central nervous system, nervous system (Clic here for more details about this article) |
5/12. Gelastic seizure with tectal tumor, lobar holoprosencephaly, and subependymal nodules: clinical report.Gelastic seizures are characterized by inappropriate, stereotyped laughter and are often first recognized when other epileptic manifestations occur. They are frequently associated with hypothalamic hamartomas. central nervous system developmental abnormalities are rarely reported with gelastic seizures. There is only one case report of gelastic seizure caused by holoprosencephaly. We report a 2-year-old girl with multiple brain structural abnormalities including tectal tumor (possibly hamartoma), multiple subependymal nodules, and holoprosencephaly. She developed seizures during the newborn period and presented with gelastic seizure and simple partial seizure at 3 months of age.- - - - - - - - - - ranking = 0.21883103569341keywords = nervous system (Clic here for more details about this article) |
6/12. holoprosencephaly with cyclopia--report of a pathological study.A rare case of a lobar holoprosencephaly with cyclopia, associated with non-nervous system anomalies is being reported.- - - - - - - - - - ranking = 0.21883103569341keywords = nervous system (Clic here for more details about this article) |
7/12. holoprosencephaly presenting as membranous aplasia cutis and diabetes insipidus: report of one case.Membranous aplasia cutis is characterized by the presence of a cystic-like nodule located at the midline of the scalp, which is surrounded by a ring of long, dark hair, called a 'hair collar' sign; it always contributes to underlying central nervous malformation. Herein, we report a 2-month-old male infant who was admitted to our ward due to diabetes insipidus complicated with hypernatremia. physical examination revealed the unique 'hair collar' sign, which is a rare presentation of congenital aplasia cutis. Imaging study revealed holoprosencephaly. Thus, the aim of this report is to remind pediatrician that in a neonate who has "membranous aplasia cutis" with hair collar sign, imaging studies, including brain sonography, computed tomography or magnetic resonance imaging of the brain, should be performed because of the great possibility of underlying central nervous system malformation.- - - - - - - - - - ranking = 1keywords = central nervous system, nervous system (Clic here for more details about this article) |
8/12. Sudden death in an infant with central nervous system abnormalities.Some deaths during the first year of life are classified as sudden infant death syndrome (SIDS), the diagnosis of which requires a complete autopsy without adequate explanation for the death. We report a 1-month-old infant whose clinical history was fairly typical for SIDS. Postmortem examination was remarkable in revealing clinically unsuspected central nervous system (CNS) abnormalities, including lobar holoprosencephaly, absence of the olfactory tracts and grooves (arhinencephaly), subependymal gray matter heterotopias, and delayed myelination. Although the CNS findings do not adequately explain the patient's sudden death, this case illustrates the need for a complete autopsy to include careful CNS evaluation, especially in any presumed SIDS death.- - - - - - - - - - ranking = 5keywords = central nervous system, nervous system (Clic here for more details about this article) |
9/12. Early prenatal diagnosis of holoprosencephaly: the value of transvaginal ultrasonography.holoprosencephaly is a rare condition characterized by different degrees of fused ventricles resulting from the failure of the prosencephalon to cleave during embryonic life. In this report we present a case of alobar holoprosencephaly diagnosed prenatally at 15 weeks' gestation in a woman with a family history of open neural tube defect. The diagnosis was initially missed because only suboptimal views of the fetal brain were obtained with transabdominal ultrasonography due to fetal position; however, a better depiction of brain anatomy was obtained using the transvaginal approach, allowing the detection of a single ventricle and fused thalami. We conclude that transvaginal ultrasonography is not only important for the early prenatal diagnosis of central nervous system abnormalities but also for enhancing brain visualization when transabdominal examination of the fetal head is limited due to maternal and fetal factors.- - - - - - - - - - ranking = 1keywords = central nervous system, nervous system (Clic here for more details about this article) |
10/12. Development of the olfactory nerve: its relationship to the craniofacies.Although absence of the olfactory bulbs is a relatively common occurrence seen in holoprosencephaly, in Kallman syndrome, and in a number of malformation syndromes, the extent to which it determines olfactory nerve development, as well as the part it plays in the morphogenesis of the nasal structures, is unknown. Cases of arhinencephaly ascertained at autopsy were studied in an effort to better understand the relationships between the olfactory nerve, bulb, and facies. Based on these studies, it is concluded that both olfactory receptor cells and olfactory nerves are present in arhinencephaly, that the olfactory nerves did not make contact with the brain in these cases, that the presence of olfactory nerves is independent of the severity of the central nervous system malformation, and that the shape of the nasal structures is not dependent on the presence of the olfactory nerve.- - - - - - - - - - ranking = 1keywords = central nervous system, nervous system (Clic here for more details about this article) |
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