Research To Date Has Shown: 1  ADHD is a neurobiologic condition whose symptoms are also dependent on the child's environment. 2  A lower level of activity in the parts of the brain that control attention and activity level may be associated with ADHD. 3  ADHD frequently runs in families.
Mosaic (genetics) In genetics, a mosaic (or mosaicism) means the presence of two different genotypes in an individual which developed from a single fertilized egg. As a result, the individual has two or more genetically different cell lines derived from a single zygote. Unusual events in cell division (mitosis).
Mosaicism is a term used to describe a condition where people have different kinds of cells in the body. Mosaic Down syndrome can thus be understood as a condition where people have some cells with the Trisomy 21 arrangement, and some cells that only posses two #21 chromosomes.Mosaic Down Syndrome remains a rare variant of Trisomy 21, and itâs usually tested for in a blood sample.Doctors look for evidence of any cells with the normal arrangement to show whether this condition is present. Number of normal cells is expressed in a percentage value based on the Trisomy cells.osaic Down syndrome can thus be understood as a condition where people have some cells with the Trisomy 21 arrangement, and some cells that only posses two #21 chromosomes. Mosaic Down Syndrome remains a rare variant of Trisomy 21, and itâs usually tested for in a blood sample.