It is difficult to predict exactly the milestones and challenges a person diagnosed with a DCC will have. Some parents notice milestones are not met as infants or toddlers. Other parents notice differences as a child progress through the early years of school. Behaviorally individuals with DCC may fall behind their peers in social and problem-solving skills in elementary school or as they approach adolescence. In typical development, the fibers of the corpus callosum become more efficient as children approach adolescence. At that point children with an intact corpus callosum show rapid gains in abstract reasoning, problem solving, and social comprehension. Although a child with DCC may have kept up with his or her peers until this age, as the peer-group begins to make use of an increasingly efficient corpus callosum, the child with DCC falls behind in mental and social functioning. In this way, the behavioral challenges for individuals with DCC may become more evident as they grow into adolescence and young adulthood.
What is the difference between a structural diagnosis (like DCC) and behavior syndromes (such as autism)?
DCC are physical diagnoses based solely on an anatomical reality – an abnormality or absence in the corpus callosum. This does not mean that DCC do not have behavioral syndromes, they clearly do. However, DCC is not a “behavioral” diagnosis such as Attention Deficit Hyperactivity Disorder (ADHD), Non-Verbal Learning Disability, Autism, or Asperger’s Syndrome. In contrast to DCC, these syndromes are diagnosed strictly based on unusual or abnormal behaviors. Although much research has been done, it is not clear what, if anything, is structurally wrong with the brain in most of these disorders. On the other hand, the diagnosis of DCC is clear and unambiguous. Once an embryo passes the 16th week, if the corpus callosum isn’t there, the diagnosis is permanent. At this point, the absence of the corpus callosum is visibly evident on brain scans.
The presence of a known brain abnormality does not preclude the assignment of a behavioral diagnosis. At this point, there is limited research regarding best treatment strategies for DCC, so it is most sensible to pursue validated treatments for an individual’s behavior pattern (regardless of whether DCC has been diagnosed or not).
Unfortunately, there is no perfect prediction about the challenges or limitations that a child may face. One neurologist told a parent in our community “only you will limit what your child will do.” We like that sentiment as encouragement to parents to celebrate the milestones and appreciate the abilities that your child has. There are many interventions and therapies that can help your child depending on the challenge and needs, especially early childhood interventions.
DCC must be diagnosed by viewing the brain, either with MRI, Computerized Axial Tomography (CT-scan or CAT scan), or pre/post-natal sonogram (ultrasound). Among these, MRI is clearly best to see DCC and any other brain abnormalities. Absence of the corpus callosum can be seen at any age after the critical period of prenatal development. A neurologist or other physician may request an MRI or CT scan of the brain. An obstetrician or neonatal specialist may request an extensive pre-natal or post-natal sonogram or MRI. The pictures typically will be examined by a neuroradiologist or pediatric neuroradiologist, who will write a report describing any unusual findings. A neurologist or other physician also may examine the scan and diagnose DCC. If that is the case, it is always wise to have a neuroradiologist re-examine the pictures to verify the diagnosis and carefully assess for any other possible abnormalities. DCC itself cannot be detected by amniocentesis.
Stem-cell research has raised expectations and hopes that we may find “cures” for some forms of nervous system damage and developmental abnormalities. At this time, it does not seem likely that DCC will be impacted by such interventions. This is due to the large number of steps in the process of development of the corpus callosum that would need to be re-instituted. Another factor is that the brain already has organized without the corpus callosum.
ACC/DCC does not have a single cause. In fact, there are multiple factors that may be involved in disrupting the formation of the corpus callosum. Among the suggested causal factors are genetics, metabolic disorders, and structural interruptions. Brain cells may not get the chemical guidance needed to grow in the right direction, possibly because of a faulty gene. Similarly, the nerve cells may not reach their destination due to lack of oxygen, poor nutrition, toxic chemicals (for example, alcohol or drugs), infections, or metabolic disturbance. Finally, the development of the corpus callosum may be stopped by some other developmental process that interrupts the initial crossing-point of callosal fibers. In these individuals, DCC may be accompanied by cysts or lipomas. There are no known medical conditions in which DCC is always present.
Some of the conditions in which DCC is usually present are: Aicardi Syndrome, Shapiro Syndrome, Acrocallosal Syndrome, Mowat-Wilson Syndrome, and Toriello Carey Syndrome. Some of the conditions in which DCC is sometimes present are: Fetal Alcohol Syndrome, intrauterine infections, maternal riboflavin/ folate/ or niacin deficiency, Dandy-Walker Syndrome, Andermann Syndrome, Arnold-Chiari II Malformation, Holoprosencephaly, Hirschsprung Disease, Occulo-Cerebro-Cutaneous Syndrome, Menkes Disease, Hydrocephalus, and others.
Physically, disorders of the corpus callosum are conditions that do not change. Once the infant’s brain is developed, no new callosal fibers will emerge. Nor will the existing callosal fibers degenerate, unless an individual gets an additional degenerative neurological condition.
Many parents worry that they may have caused their child to have brain damage or may fear that it is a condition that will recur in future children. In addressing those questions, it is important to remember that it is usually impossible to establish the reason a child has DCC.
Genetic testing may reveal a genetic abnormality or syndrome that is the underlying cause of the DCC. In these cases, the parents or the individual with DCC will want to consult a genetic counselor prior to becoming pregnant with another child. In the absence of an identified genetic abnormality, it is extremely difficult to find a specific cause of DCC. Multiple possible causes appear to exist, and genetic testing does not always reveal what that cause might be. If it is not genetic, it was caused by something that happened during the first trimester of pregnancy. While it is understandable that parents will want to know “why this happened,” in many cases they may never know. Therefore, it may be important to shift the focus from asking “why?” to asking, “what can we do to cope with the diagnosis?” and “how can we best help our child?”
The early years of childhood present a crucial window for developing neural pathways in the brain. Early intervention after a diagnosis in infant or young child is very important. Local school districts offer early intervention services or search for private clinics or resources for birth to age 3 in your area. Your pediatrician should be able to put you in contact with local service providers. Some of the services you may receive include PT (Physical Therapy), OT (Occupational Therapy) & SPI (Speech Therapy). Early intervention resources can be found at the National Early Childhood TA Center website. Contact the Department of Developmental Disabilities in your area for information about respite and/or rehabilitation care services for your child. Typically, you need to schedule an appointment for the intake meeting that determines qualifying for services.
Disorders of the corpus callosum are not diseases or illnesses that can be cured. DCC are abnormalities of brain structure and are conditions that one must “learn to live with” rather than hope to recover from. Long term challenges are associated with disorders of the corpus callosum, but this in no way suggests that individuals with DCC cannot lead productive and meaningful lives.