Neurogenetic aspects of communication disorders.
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Brain↗
Biomedical subjects
G B Schaefer
Publications and source records attributed to G B Schaefer.
Tetrasomy of the short arm of chromosome 9: prenatal diagnosis and further delineation of the phenotype.
A fetus with multiple malformations was identified by prenatal ultrasound investigation. Cordocentesis and fetal lymphocyte chromosome analysis demonstrated a model number of 47 chromosomes. The extra chromosome material was identified as an isochromosome of the entire short arm of chromosome 9 with no involvement of the heterochromatic region of the long arm [47,XY, + i(9p)]. This represents the first report of prenatal diagnosis of tetrasomy 9p. Further delineation of the phenotype is discussed.
Aneuploidy↗
Clinical and morphometric analysis of the hypoplastic corpus callosum.
A total of 307 children were evaluated over a 3-year period in our neurogenetics clinic. Review of their medical records demonstrated 26 patients with diagnoses of anomalies of the corpus callosum. Morphometric analysis was performed on those 23 patients qualitatively assessed as having a hypoplastic (small, but morphologically intact) corpus callosum. Morphometric data were compared with clinical correlates for each patient. From these data, we conclude that the hypoplastic corpus callosum is not a normal variant of development but rather an indicator of a more fundamental abnormality of cerebral development.
Agenesis of Corpus Callosum↗
Cerebral abnormalities in thanatophoric dysplasia.
Neuropathologic evaluation of two infants with thanatophoric dysplasia displayed typical gross morphologic characteristics and a distinct pattern of brain malformations, including anomalies of the temporal lobe gyri and hippocampus, neuroglial heterotopias, fiber tract hypoplasia, and dysplasia of deep nuclei. Increased numbers of horizontal cells of Cajal-Retzius were striking in frequency and distribution. The pattern of abnormalities suggests arrest of cerebral cortical ontogeny late in development. As with the mucopolysaccharidoses, a shared common metabolic pathway is a potential mechanism for development of widespread bony and somatic abnormalities and associated central nervous system anomalies.
Brain↗
Management and outcome of two pregnancies in a woman with craniodiaphyseal dysplasia.
Hyperostotic bone dysplasias are characterized by progressive hyperostosis and sclerosis of the cranium and facial bones. As a result of progressive bony overgrowth, intracranial pressure may increase and lead to brain and nerve compression, cranial nerve palsies, and an increased incidence of seizures. The long bones often exhibit defective modeling as well as variable degrees of metaphyseal and diaphyseal hyperostosis. In addition, the axial skeleton (including the pelvis) is often hyperostotic and sclerotic. The clinical features of these disorders may have relevance to the outcome of pregnancy; however, there are no reports on the management and pregnancy outcome of patients affected with hyperostotic bone disease. In this report, we describe the course of two pregnancies in a woman with craniodiaphyseal dysplasia (a rare craniotubular dysplasia). Prenatal assessment, method of delivery, choice of anesthesia, and neonatal management are discussed. Although this disorder is rare, the pathophysiologic considerations relevant to pregnancy outcome may be applicable to the management of pregnant women with other hyperostotic bone dysplasias.
Adult↗
Age-related changes in the relative growth of the posterior fossa.
We have established a normative data set for the relative size of the structures of the midline posterior fossa from birth to 90 years old. Data were obtained from morphometric analysis of midsagittal magnetic resonance imaging scans of the brain utilizing a simple image analysis system. There are several significant changes in the size of these structures with an increase in chronologic age. The relative size of the cisterna magna decreases with age. Anterior cerebellar vermal lobules (I through V) appear to grow more rapidly than the rest of the cerebellum. Other, less significant, trends include a decrease in the overall size of the cerebellum, superior posterior vermal lobules (VI and VII) and inferior posterior lobule (VIII) with an increase in age. It is, therefore, necessary to use age-standardized normative data when making morphometric correlations with clinical disorders.
Adolescent↗
Quantitative morphometric analysis of brain growth using magnetic resonance imaging.
Using a simple image analysis system, we have established normative data obtained from magnetic resonance imaging (MRI) scans for the relative size and growth of the major structural domains of the brain. Midsagittal scans of the head were analyzed in 95 subjects aged 0 to 20 years. Only scans with no demonstrable structural abnormalities of the brain were utilized. Age-related changes in the relative growth of specific structures were calculated by dividing patients into 5-year age increments. No age-related changes were found in the size of the posterior fossa, supratentorial intracranial space, or cisterna magna relative to the total intracranial vault space. A significant (P less than .01) increase in the size of the corpus callosum relative to that of the supratentorial structures and relative to the total intracranial vault space was noted to occur between the 6- to 10-year-old and 11- to 15-year-old age groups. This may reflect an increase in myelination of the corpus callosum that occurs during this period. A small reduction in the ratio of the posterior fossa to the supratentorial space was found between the 0- to 5-year-old and the 6- to 10-year-old age groups, but the biological significance of this difference is uncertain. It appears from these data that quantitative analysis of MRI scans can be used to draw objective conclusions about the relative sizes and growth of the major brain structures. The development of normative data for these structures and the simplicity of the methodology should have many clinical applications in the assessment of aberrant brain development.
Adolescent↗
Neuroimaging findings in Alexander's disease.
We present the findings from magnetic resonance imaging, computed tomographic scan, and single photon emission computed tomography of the brain in a 2-year-old girl with Alexander's disease. Computed tomographic scans showed prominent low-density white matter throughout the cerebral hemispheres. Magnetic resonance imaging showed increased T2 signal from the cerebral white matter but not the cerebellum or brain stem. Single photon emission computed tomography revealed diminished cerebral metabolism, particularly in the frontal regions, as compared with the cerebellum.
Astrocytes↗
Hypoplastic corpus callosum in ocular albinism: indication of a global disturbance of neuronal migration.
Ocular albinism is distinguished from the more common oculocutaneous albinism by the presence of normal pigmentation of skin and hair in the former condition. Recent studies of ocular albinism have shown that the hypopigmentation of the optic fundus is associated with a number of anomalies of neuronal wiring involving the visual system. We present a patient with ocular albinism who also has a hypoplastic corpus callosum as determined by analysis of midsagittal magnetic resonance imaging scans. Previous studies of the hypoplastic corpus callosum indicate that this anomaly is a defect in neuronal migration as well. The finding of a hypoplastic corpus callosum in a patient with ocular albinism suggests a more generalized defect in neuronal migration not limited to the visual system.
Abnormalities, Multiple↗
Diabetic ketoacidosis at the Children's Hospital of Oklahoma: a review on presentation and management.
Examination of 394 cases of diabetic ketoacidosis presenting at the Children's Hospital of Oklahoma from 1975 to 1987 has indicated a higher frequency of very young patients with low insulin requirements and frequent presentation in the winter months. The severity of the preceding hyperglycemia varies widely as indicated by the range of glycosylated hemoglobin values at the time of diagnosis. In addition we have identified measures to prevent the main hazards occurring during therapy which are related to potassium replacement and correction of dehydration without causing cerebral edema. The general principles of management are reviewed and we have selected certain aspects for emphasis and discussion based on past experience.
Child↗
Dominantly inherited childhood gigantism resembling Sotos' syndrome.
Excessive growth in infancy and onset of puberty at age four was observed in a boy with features resembling Sotos syndrome. Early development of secondary sexual characteristics and advanced osseous maturation were observed. The family history was significant; excessive weight gain tended to occur in female family members in association with rapid growth in infancy and childhood. A delayed insulin response to glucose was observed in both mother and sister, and diabetes developed during his mother's gestation. These observations suggest that undetermined factors associated with excessive growth may be inherited as a dominant trait with variable expression.
Child↗
Acidophil stem-cell pituitary adenoma in a prepubescent female. Case report.
Acidophil stem-cell pituitary adenomas account for less than 5% of pituitary tumors. Only 15 cases have previously been reported, with a mean age of occurrence of 38.7 years. A case of this unusual tumor is reported in a prepubertal girl. Clinical symptoms included prominent behavioral disturbance with associated headache and visual disturbance. There was marked elevation of serum growth hormone concentration without clinical features of growth hormone excess, suggesting that this tumor has the capacity to excrete biologically inactive hormones. The clinical and pathological features of this unusual invasive pituitary tumor are reviewed; the age spectrum for this neoplasm must be expanded to include prepubertal children.
Adenoma, Acidophil↗
Agnathia, holoprosencephaly, and situs inversus: report of a case.
We present the first documented case of agnathia-holoprosencephaly (an uncommon form of craniofacial anomaly) associated with situs inversus. This case may represent the concordance of multiple field complex anomalies, but the possibility of a major midline malformation (situs inversus) caused by a timed insult (environmental or genetic) which affects multiple structures and occurs concurrently with a major field defect during early embryogenesis cannot be excluded.
Abnormalities, Multiple↗
Achondroplasia and parental age.
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Achondroplasia↗
Macro cisterna magna: a marker for maldevelopment of the brain?
Enlargement of the cisterna magna occurs in as many as 0.4% of reported patients and generally has been believed to represent a normal variant. Differentiation from Dandy-Walker malformations and other cystic structures has been emphasized. We reviewed 1,260 consecutive computed tomography reports in patients younger than 21 years of age and examined all scans in which enlargement of the cisterna magna was considered an isolated finding. Fourteen patients were identified (incidence: 1%). The primary reasons for obtaining computed tomographic scans included various clinical conditions but excluded symptoms indicative of posterior fossa disease. Developmental or neurologic abnormalities were present in 62% of these patients. Macro cisterna magna should not be dismissed as a normal variant, although the neurologic findings may not be specifically localized to the posterior fossa. This finding may be a marker for abnormal brain function most likely due to subtle disturbances in brain development.
Brain↗
Wide cavum septum pellucidum: a marker of disturbed brain development.
A wide cavum septum pellucidum defined as a separation of greater than 1 cm of the leaves occurs uncommonly. Nine children with wide cavum septum pellucidum were studied; 8 were abnormal. Observed abnormalities included cognitive impairment (8), seizures (4), hypoplasia of the corpus callosum (4), optic nerve hypoplasia (2), and growth failure (4). The incidence of intellectual dysfunction, the association with midline anomalies of the brain, and growth failure all suggest that wide cavum septum pellucidum may represent part of a spectrum of midline brain anomalies.
Adolescent↗
Partial agenesis of the anterior corpus callosum: correlation between appearance, imaging, and neuropathology.
Two patients with partial (semilobar) holotelencephaly are reported with apparent partial agenesis of the corpora callosa. These patients are of interest because they appear to possess the posterior portion of the corpus callosum but not its anterior component. Because the corpus callosum develops in the commissural plate rostrally and is elaborated in a rostral-caudal gradient, this apparent lack of the rostral component is embryologically puzzling. The neuropathologic studies of 1 patient resolved the apparent discrepancy between magnetic resonance imaging and embryology of the corpus callosum. With these data, we addressed the embryologic factors that may explain this malformation.
Abnormalities, Multiple↗
Medical genetic evaluation for the etiology of hearing loss in children.
The purpose of the medical genetic evaluation is to identify the etiology of the hearing loss. To do so requires a multidisciplinary team that includes the otolaryngologist, audiologist, medical geneticist, and radiologist. A number of tests and procedures are now available to assist in the search for the cause of hearing losses. The importance of sensitivity when providing genetic counseling is emphasized. Molecular genetics offers potential for continued progress in understanding the etiologies of hearing loss. Recent advances in this area are discussed.
Child↗