mosaizmus

Mosaicism refers to the presence of two or more cell populations that have different genotypes within a single individual or organism. These different cell lines can arise from a single fertilized egg that carries a mutation or from a mutation occurring after fertilization in a developing embryo. Mosaicism can occur in somatic cells, affecting only specific tissues or organs, or it can occur in germline cells, meaning the mutation can be passed on to offspring.

The genetic makeup of the different cell populations can vary. For instance, a person might have some cells with a normal chromosome number and others with an extra chromosome (trisomy) or a missing chromosome (monosomy). This can also apply to specific genes, where some cells have a normal gene sequence and others carry a mutation. The extent and location of mosaicism can significantly influence the phenotype, or observable characteristics, of an individual. Mild cases may go unnoticed, while more extensive or critical mosaicism can lead to a range of developmental abnormalities or specific genetic disorders.

Diagnosing mosaicism often involves genetic testing, which may require analyzing cells from different tissues to identify the presence of distinct cell lines. The implications of mosaicism are broad, impacting areas such as genetic counseling, reproductive medicine, and the understanding of various genetic conditions.