The presence of a gene mutation for a disease trait in some yet not all of an individual's sexual reproductive cells (germ cells) within the ovaries or testes (gonads). Germline mosaicism is sometimes suspected when parents have more than one child with a genetic disorder transmitted as a dominant trait yet neither parent appears to be affected by the condition.
Two or more groups of germ cells in a single individual, with different genetic or chromosomal constitutions. If a parent has germline mosaicism in their gonads for a dominantly inherited condition, they will be unaffected by the condition, but may be at risk of having more than one affected child .
the presence of reproductive cells (sperm or egg) of different genetic make-up. For example, an average-statured parent may some reproductive cells with the mutation for achondroplasia. This would give them a chance of having more than one child with achondroplasia.
Two or more genetic or cytogenetic cell lines confined to the precursor (germline) cells of the egg or sperm; formerly called gonadal mosaicism
Two populations of cells making up the germline of one individual.
Germline mosaicism is a genetic mutation that arises at the germ line, or gonadal level, meaning that some of either the mother's eggs or the father's sperm cells carry the mutation. The other cells in the body do not have the mutation, and the parent doesn't show any symptoms. TSC results when an egg or a sperm cell that carries the mutation is involved in fertilization.