Agenesis of the Corpus Callosum

Agenesis_Corpus_Callosum_smlThe Agenesis of the Corpus Callosum

Generally, Corpus callosum Agenesis refers to a congenital abnormality in the brain which occurs when the corpus is not able to develop as it should during the prenatal early period. It is important to note that this abnormality can occur as medical or physical conditions or as an isolated condition or by association with other abnormailites of the brain. Corpus callosum is the largest brain’s middle structure that; starts to develop around tenth to eleventh week of pregnancy, consists of over two hundred million nerve fibers which connect the two hemisphere of brain, transfers and integrates sensory, cognitive and motor information between the cerebral hemispheres and continues to mature throughout the pregnancy period and into both childhood and adolescence. It is important to note that the type of callosal abnormality that can occur mainly depends on the timing and cause of disruption to the prenatal development of brain. The corpus callosum will not develop later in case it does not form during the prenatal period. There are some variations in how the callosal conditions may be describes by medical providers and in medical reports currently.

Some of the most commonly used terms to describe these conditions include; ACC or Agenesis of the corpus callosum is a condition in which a portion or all of the corpus callosum including both partial and complete ACC is absent, agenesis of the Corpus callosum (AgCC), acronym that has appeared more recently in some research literature and is where a part or all of the corpus callosum is absent, C-ACC refers to Complete corpus callosum agenesis in which none or only a part of corpus callosum exists, P-ACC, part agenesis of the corpus callosum whereby a portion of an individual’s corpus callosum is absent and in most cases it is the posterior portion that is absent, Hypogenesis of the corpus callosum which is another term used to describe Agenesis corpus callosum sometimes, Hypoplasia of the corpus callosum in which the corpus callosum is present even though abnormally thin and the Dysgenesis of a corpus callosum whereby the corpus callosum is present despite the fact that it is malformed in some way and includes Hypoplasia and partial agenesis of the corpus callosum.

It is usually not very easy to determine the exact incidence of agenesis corpus callosum and many other callosal disorders due to the fact that there is need for a brain scan to diagnose the condition and there is no one that know the number of people having agenesis of the corpus callosum but do not know. The increased use and development of sophisticated and new imaging technologies using clinical auditing software and prenatal technologies are significantly assisting researchers and medical professionals to identify this medical condition earlier in life and across the lifespan. Callosal disorder is estimated by many sources to happen in up to four individuals per one thousand in the general population and happens more frequently among individuals with developmental disabilities. A group of researchers in U.S recently reported an incidence rate of one in four thousand births based on a review of neonatal and prenatal imaging studies. However, these researchers suggested that this may actually be an under estimate of the true rate occurrence.

Usually, it is very difficult to determine the definite cause of the callosal abnormality even though medical testing including the genetic testing can provide valuable information sometimes. Agenesis of the corpus callosum researchers including genetics specialists are currently working around the clock to gain a clearer and better comprehension of the causes of these conditions. It is important to know that some of the possible causes include but not limited to; inherited genetic factors, prenatal injuries or infections, prenatal exposures, metabolic disorders, structural blockages like cysts, chromosome errors and many other unknown factors.

Callosal conditions are basically diagnosed by a brain scan which involves; prenatal magnetic resonance imaging which provides the most detailed information, prenatal ultrasound and computerized tomography. Even callosal abnormality can happen in the form of an isolated type of condition in an individual, it good to know that this condition may also happen in association with medical or physical conditions or with other brain abnormalities. Agenesis corpus callosum can happen as along with a specific grouping of congenital abnormalities or in association with an abnormality of the chromosome. Because of this, there are some individuals with callosal conditions who are quite healthy while there are others who may have additional physical or medical conditions that impact health and development in various ways.

There are a number of more common syndromes and anomalies associated with agenesis corpus callosum. For instance, the brain anomalies that occur with agenesis of the corpus callosum sometimes include hydrocephalus, schizencephaly which is deep cleft in brain tissues, migration disorders, Anorld-chiari malformation and holoprosencephaly which is failure of the forebrain to divide into its lobes. Some of the other conditions that are associated with ACC include but not limited to Shapiro, Acrocallosal, Aicardi, Menkes, Andermann, Mowat and FG.

Families and individuals usually find it very helpful to consult genetic specialist after the first diagnosis of this disorder for diagnostic purposes and to help in future planning of the family.

It is important to note that research on the callosal disorders impact is in early stages and there is new information that continues to come up. Current researchers however suggests that individual with callosal disorders share some common communication, physical, behavioral, cognitive and social features. But there are the individual differences that exist among people with callosal disorders ranging from cognitive challenges and subtle developmental to more disability. All these differences are due in part to whether the person has additional medical, behavioral or physical conditions which also affect intellectual, health and development disabilities.

There are several characteristic associated with individual suffering from agenesis of the corpus callosum. Health or physical related characteristics include but not limited to; vision impairments which include far or near sightedness, strabismus, problems with depth perception and nystagmus. There is also low muscle tone, early feeding difficulties or gastric reflux or chewing and swallowing difficulties, high tolerance to pain, abnormal facial and head features, sleep difficulties, spasticity or seizures, hearing impairments, elimination problems which includes chronic constipation, and skeletal defects, genetic conditions, genitor urinary defects, metabolic disorders and cardiac abnormalities which are less common.

The developmental characteristics include delays in attaining motor milestones like walking, sitting or riding a bike, early language and speech delays mainly in expressive communication, delayed toilet training and clumsiness or poor coordination. There are also the social or behavioral characteristics which include social immature, lack of self awareness, generally happy disposition, inability to take others perspective, problems in comprehending and acting on others social cues, difficulty in maintaining keen attention, hyperactivity, fearfulness, compulsive or obsessive behaviors and challenges with peer interactions as well as relationships which seem to increase with the complexity and age of the social situations.

Even though mental retardation can happen in association with callosal disorders, it is important to note that people with agenesis of the corpus callosum may also have intelligence that is normal. However, it is suggested by research that even those individuals with agenesis corpus callosum and normal intelligence may experience subtle cognitive and neuropsychological challenges. These include, difficulty imaging the consequences of their own behavior and action, difficulty comprehending abstract concept or language, difficulty comprehending sarcasm, slang and many other humor that are sophisticated, difficulty in understanding other people’s emotions and perspective, communicating false information while perceiving that it is true, limited sight into their own limitations and behavior, difficulties with abstract reasoning, complex tasks, problem solving like managing money, misinterpretation of other people’s non verbal communication and early language and speech delays especially with expressive communication.

It is important to note that since this disorder forms early in fetal development, it will not develop later in case it does not develop at that time. Currently there are no proved medical treatments specifically for the callosal disorders. However, there is availability of treatment for other medical and physical conditions like sensory impairments, hydrocephaly, and seizure which are sometimes associated with callosal conditions. To add on that, adult and children suffering from this disorders can benefit from educational support, adult services and individualized developmental therapies.

It is always good to consider obtaining consultations, interventions and evaluations from various allied health, medical, social work and educational professionals, starting early in life and proceeding throughout childhood and into maturity. Some of the professionals who are actually potential resources for individuals with agenesis corpus callosum and other callosal conditions include but not limited to; neurologists, geneticists, endocrinologists, early childhood special educators, early intervention specialists, behavioral psychologists, adult service providers, physical therapists, occupational therapists, orthalmologists, pediatrician or pediatric nurse practitioners, neuropsychologists, special educators and language-speech pathologists.

Corpus Callosum SchematicThere are some children who only have mild learning problems with the agenesis, but have normal intelligence. However, there are some children who may have severe handicaps like mental retardation, seizure, autism or cerebral palsy disorders. Generally, how one child falls on this spectrum mainly depends to some extent on whether other development problems of the brain are detected on the MRI and whether there is any problem with the chromosomes of the child. The nerve endings of the corpus callosum continue their growth throughout and become more developed even in via teenage period. During this phase in their development, it is worth noting that children with a corpus callosum that is normally made makes progress in their problem solving, abstract reasoning and there is maturity of their social skill.

Remember that a child with a genesis corpus callosum may have sustained with his or her peers till this age, but they may start to drag behind in social functioning and school work. Thus, the symptoms of agenesis corpus callosum can actually become more evident as they grow into puberty and early maturity.

In case your physician sees a problem with the corpus callosum, he or she may prefer you for a number of tests in case they are yet to be done. Such tests can involve a more detailed ultrasound scan mostly referred to as an ultrasound level 2 or fetal survey, amniocentesis to analyse the genetic profile of your fetus as well as looking for any signs of infection. There is also the fetal resonance imaging which is another safe and effective way to look at the brain of the fetus. MRI provides pictures of the fetus’s brain using different technology compared to the ultrasound. Since it basically uses a different efficient technology, it s worth noting that fetal resonance imaging can easily detect other problems in the brain of your fetus that cannot be easily detected on ultrasound.

Since there is not treatment before birth fetuses with agenesis of the corpus callosum, it is worth noting that treatment after birth entails managing the symptoms of the child well. During pregnancy, it is essential for an expectant mother to acquire detailed diagnosis through detailed ultrasound, MRI and amniocentesis so as to determine if there are any other problems. Consider getting the appropriate specialists to help you in case it is revealed that there is more severe handicaps that require long term care.

It is important to know that the prognosis or outlook with agenesis of the corpus callosum is variable. This condition does not result to death in many patients. Even though most children with this condition live and have average intelligence, neuropsychological testing that is carefully done shows subtle differences in higher cortical function than to persons of similar education and age without agenesis corpus callosum. It is very vital for children with agenesis corpus callosum accompanied by delay in development or seizure disorders to be screened for metabolic conditions. It is worth noting that the mental retardation that is associated with agenesis corpus callosum is not always progressive.

In rare cases, an abnormal corpus callosum can actually be determined from an auxiliary brain scan that is done for another reason like head injury. Also development of other problems like seizure may lead to further investigations such as a brain scan. This can come as a considerable shock for an individual diagnosed in adulthood or late adolescent since they are usually not aware that there has been any significant change in their brain formation. This can also feel like an explanation for some individuals about the difficulties they have gone through in their life.