What is Epilepsy?
A chronic neurological disorder, epilepsy is characterised by recurrent seizures that happen due to the alterations in the brain structure and its functions. In medical terms, a seizure is defined by a sudden rush of electrical impulses that activate in the brain. These impulses can cause vigorous shaking for a prolonged (tonic-clonic seizures) or brief (infantile spasms) period. Epilepsy in most people can go unnoticed initially and can also be difficult for doctors to narrow down the exact causes.
However, in some cases epilepsy can be caused by the following reasons:
- Genetic Factors – Genetic abnormality can cause epilepsy
- Brain Condition – An injury or trauma to the brain can trigger causes of seizures and may result in epilepsy
- Developmental Disorders – Epilepsy is closely linked to autism and neurofibromatosis which are developmental disorders
- Prenatal Injury – Babies before being born can have brain damage due to poor nutrition, infection or oxygen deficiency
- Infectious Diseases – Viral encephalitis, AIDS, meningitis can cause epilepsy
What is Down Syndrome?
A genetic disorder, Down Syndrome is also known as trisomy 21 and is characterised by the presence of an additional chromosome. It is a lifelong condition where the additional chromosome causes a set of mental and physical traits. An average person has 46 chromosomes, whereas people with Down syndrome have 47 chromosomes. The extra chromosome changes the way the brain and body develop. People with Down syndrome have the following symptoms or characteristics:
- Distinctive facial features such as small ears, slanting eyes, small mouth and a flat face
- Below-average intelligence
- Short neck, legs, and arms
- Loose joints and low muscle tone
- In some cases, children are born with congenital heart disease, breathing, ear and intestinal problems
Dr. Mayank Chawla, Senior Consultant, Max Hospital, Gurgaon, says, children with Down syndrome tend to face abnormalities that are mentioned above. Furthermore, they are also at a much higher risk of developing leukaemia and may even suffer from Alzheimer’s disease.
A Link between Epilepsy & Down’s Syndrome
Epilepsy is rarely considered as a major clinical feature of Down syndrome. About 5-6 % of children with Down syndrome suffer from this condition. There are two different age groups where Epilepsy is associated with this condition- A childhood onset and late adult onset.
Infantile spasms or West’s Syndrome is more frequent in Down syndrome than in general population. Lennox - Gastaut syndrome is also more common in Down syndrome as compared to general population. Here the onset is later and reflex seizures are more frequent. The treatment of these conditions is no different from that of a child who does not have Down syndrome. In face patients with Down syndrome achieve a better seizure control as compared to others. The childhood epilepsies in Down syndrome are not associated with the onset of Dementia. Another observation is that Non- Asians individuals with Down syndrome are more likely to develop seizures. Some Nutritional factors may account for this.
Adult-onset epilepsy in Down syndrome is associated with progressive decline in cognitive and motor function. Language function declined significantly more rapidly in adult patients with seizures. It has been observed that 50% of individuals with Down syndrome above the age of 45 yrs develop Alzheimer disease and advanced Alzheimer’s disease alone may be an important risk factor for the development of seizures in adults. Up to 80% of demented individuals with Down syndrome is related to Alzheimer disease development. The adult-onset Epilepsy in Down syndrome has some electro-clinical characteristics and behave as progressive myoclonic epilepsy. The gene for a special type of Progressive Epilepsy is located on chromosome no. 21. The extra gene located on the 3rd copy of chromosome 21 may be responsible for this condition. Further research is ongoing in their area.