Mosaicism

Mosaicism Symptoms & Signs

The symptoms depend on what genetic change is mosaic.

For example, if a person has two populations of cells -- one normal and one missing an X chromosome -- the symptoms are usually milder versions of those seen in Turner syndrome. Turner syndrome results when 100% of cells lack an X chromosome. If only a fraction of cells lack this chromosome, the symptoms will vary from milder to none at all. The severity increases as the percentage of mosaicism increases. If 90% of cells are abnormal, symptoms are likely; if only 10% are abnormal, the person may be unaware that anything is wrong.

Gonadal mosaicism is a different situation. In that case, the mosaicism is in the parent's ovaries or testes. Any individul egg or sperm either has the mutation or not. Therefore, if conception involves one of these mutant sex cells, the resultant child will not be mosaic, but will simply have the genetic disease caused by that particular mutation.