What is Agenesis of the Corpus Callosum?
Agenesis of the corpus callosum (ACC) is a rare congenital abnormality in which there is a partial or complete absence (agenesis) of the corpus callosum. The corpus callosum is the area of the brain which connects the two cerebral hemispheres. In most patients, ACC is diagnosed within the first two years of life. It may occur as a severe syndrome in infancy or childhood, as a milder condition in young adults, or as an asymptomatic incidental finding. The first symptoms of ACC are usually seizures, which may be followed by feeding problems and delays in holding the head erect, sitting, standing, and walking. The seizures may be caused by a very common disorder called infantile spasms, which is associated with ACC. There may be impairments in mental and physical development, hand-eye coordination, and visual and auditory memory. Hydrocephaly may also occur. In mild cases, symptoms such as seizures, repetitive speech, or headaches may not appear for years. Female children may also have a specific syndrome, Aicardi's syndrome, in addition to ACC and infantile spasms, in which there is severe mental retardation and chorioretinal lacunae (lesions of the retina of the eye). ACC may occur as an isolated condition or in combination with other cerebral anomalies including Arnold-Chiari malformation and Dandy-Walker syndrome, Andermann syndrome (with progressive neuropathy), schizencephaly, holoprosencephaly, and migrational anomalies. ACC is also sometimes associated with complex multi-system malformations and with several chromosomal anomalies, including trisomy 13 and 18. There are non-nervous system malformations that may occur both with and without chromosomal aberrations such as midline facial defects.
HYDROCEPHALAUS-a condition marked by dialation of the cerebral ventricles, most often occuring secondarily to obstruction of the cerbrospinal fluid pathway and accompanied by an accumualtion of cebrospinal fluid with the skull
HEMISPHERE-half of any spherical structure or organ, as the cerebral hemisphere or the cerebellar hemisphere
SPINA-BIFIDA-a develpomental anomaly characterized by a defective closure of the bony encasement of the spinal cord, through which the cord and meninges may or may not protrude
SPINA-BIFIDA OCCULTA-spina bifida in which there is a defect of the vertbral canal without protrusion of the cord or meninges
ARNOLD CHIARI MALFORMATION a congential anomaly in which the cerebullum and medula oblonta, which is elongated and flattened, protrude down into the spinal canal through the foramen magnum, it may be associated with many other defects, such as, SPINA BIFIDA OCCULTA
MICROCEPHALY-abnormal smallness of the head
MACROCEPHALY-excessive size of the head
SEPTO-OPTIC DYSPLASIA-also known as deMORSIERS syndrome,a syndrome of hypoplasia of the optic disk with other occular abnormalities, absence of the septum pellicudum, and hypopituitarism, leading to growth hormone deficeney
PITUTARY GLAND-an epithelal body located at the base of the brain in which the sella turcica, attached by a stalk to the hypothalamus, from which it receives an important neural and vascular out flow. It consists of two lobes of different emybroyonic orgin, the anterior lobe which secretes most of the hormones and the posterior lobe, which stores and releases neurohormones that it receievs from the hypothalamus.
HYPOTHALMUS-the ventral part of the diencephalon that forms the floor and part of the lateral wall of the third ventricle.It controls endocrine activity and many somatic features.e.g. general regulation of water balance, body temperatures, sleep, and food intake
HYOPLASAIA-incomplete develpoment or underdevelpoment of an organ or tissue
GENE- a segment of DNA molecule that contains all the information required for synthesis of a produc, including coding and non coding sequences. it is the biological unit of heredity, self reproducing and transmitted from apernt to progeny. Each gene has a specfic position on the chromosome map.
CHROMOSOME-transmits genetic informatyion and is assoicated with RNA and histones;during cell division. the material composing the chromsome is compactly coiled, amking it visible with appropraite staining and permitting it`s movement in the cell with minimal entanglement. each organism of a species normally has a characteristic number of chromosomes in it`s somatic cells, 46 being the normal number in man, including the the two XX or which determine the sex of the organism
ANOAMLY-marked deviation from the normal standard, especially as a result of a congential defect.
CONGENTIAL-exsisting at and usually before birth.
EPILEPSY-any group of disturbances characterized by paroxysmal transient disturbances of the brain function that may be mainifested as eposodic impairment or loss of consciousness, abnormal motor phenomena, psycic, or sensory disturbances, or perturbation of the automatic nervous system. A single episode is called a SEIZURE.Many types of epilepsy are combinations of different kinds of seizures. Symptoms are due to paroxysmal disturbance of the electrical activity of the brain.
COLPOCEPAH Y - In this disorder, there is abnormal enlargement of the occipital horns - the rear portion of the cavities or chambers of the brain. Colpocephaly results from underdevelopment or lack of thickening of the white matter in the posterior cerebrum
Torticollis- (wry neck) is a congenital or acquired condition of limited neck motion in which the child will hold the head to one side with the chin pointing to the opposite side. It is the result of the shortening of the sternocleidomastoid (neck) muscle. In early infancy, a firm, non-tender mass may be felt in the midportion of the muscle. The mass will go away and be replaced with fibrous tissue. If untreated, there can be permanent limitation of neck movement. There may be flattening of the head and face on the affected side