What is a mosaic diagnosis?

Mosaicism or mosaic Down syndrome is diagnosed when there is a mixture of two types of cells. Some have the usual 46 chromosomes and some have 47. Those cells with 47 chromosomes have an extra chromosome 21. Mosaicism is usually described as a percentage.

What does mosaic mean in genetics?

What is mosaicism? Mosaicism occurs when a person has two or more genetically different sets of cells in his or her body. If those abnormal cells begin to outnumber the normal cells, it can lead to disease that can be traced from the cellular level to affected tissue, like skin, the brain, or other organs.

What is the difference between mosaic Down syndrome and Down syndrome?

Down syndrome is a genetic disorder that results in an extra copy of chromosome 21. People with mosaic Down syndrome have a mixture of cells. Some have two copies of chromosome 21, and some have three. Mosaic Down syndrome occurs in about 2 percent of all Down syndrome cases.

What causes mosaicism?

This phenomenon is known as mosaicism, and it can be caused by spontaneous DNA mutations, spontaneous reversion of an existing DNA mutation, epigenetic changes in chromosomal DNA, and chromosomal abnormalities. Furthermore, mosaicism can be associated with changes in either nuclear or mitochondrial DNA.

What does low level mosaic mean?

A low-level mosaic embryo would have mostly normal cells and a lower percentage of abnormal cells. A high-level mosaic embryo would have mostly abnormal cells and a lower percentage of normal cells. An important point to make is that mosaicism happens after fertilization, that is after the egg and sperm meet.

Is mosaic Down syndrome a disability?

The symptoms of Mosaic Down syndrome must significantly impair the ability to achieve gainful employment in order to qualify for Social Security Disability benefits. The SSA evaluates each applicant on a case by case basis.

Does mosaic Down syndrome affect intelligence?

One American study of 30 children and one Japanese study of 8 children compared them with matched children with standard Down syndrome and their findings suggest that groups of children with Mosaic Down syndrome have a higher average IQ.