Children whose seizures have some of these features are less likely to have the syndrome of Childhood Absence Epilepsy. 1  An absence seizure with mild clonic components involves mild, often subtle twitching of the eyelids, the corners of the mouth, and sometimes the arms.
1 Trisomy 21 â More than 90% of Down syndrome cases are caused by trisomy 21. 2  An extra chromosome (chromosome 21) originates in the development of either the sperm or the egg. 3  When the egg and the sperm unite to form the fertilized egg, three (rather than two) chromosomes 21 are present.
Down syndrome is a lifelong condition. But with care and support, children who have Down syndrome can grow up to have healthy, happy, productive lives. Down syndrome is caused by a problem with a baby's chromosomes. Normally, a person has 46 chromosomes.But most people with Down syndrome have 47 chromosomes.ost children with Down syndrome have: 1  Distinctive facial features, such as a flat face, small ears, slanting eyes, and a small mouth. 2  A short neck and short arms and legs. 3  Low muscle tone and loose joints. 4  Muscle tone usually improves by late childhood.