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).
Mosaic (genetics) In genetics, a mosaic, or mosaicism describes the presence of two or more populations of cells with different genotypes in one individual, who has developed from a single fertilized egg. Mosaicism has been reported to be present in as high as 70% of cleavage stage embryos and 90% of blastocyst-stage embryos derived from in vitro fertilization.