hemizygous

{
  "id": "MLC-T-ONC-003785",
  "term": "hemizygous",
  "field": "Oncology and biomedicine",
  "definitions": [
    "A term that describes a person who has only one copy of a gene rather than the usual two copies. Hemizygosity can occur under normal conditions. For example, because most males have one X chromosome and one Y chromosome, they are hemizygous for genes on those chromosomes. Hemizygosity can also occur under abnormal conditions, such as when two copies of a gene should be present but one is missing. For example, Turner syndrome occurs when a female inherits only one copy of the X chromosome instead of the usual two copies.",
    "Describes an individual who has only one member of a chromosome pair or chromosome segment rather than the usual two. Hemizygosity is often used to describe X-linked genes in males who have only one X chromosome. This term is sometimes used in somatic cell genetics where cancer cell lines are often hemizygous for certain alleles or chromosomal regions."
  ],
  "references": [
    "NCI Dictionary of Cancer Terms",
    "NCI Dictionary of Genetics Terms"
  ],
  "url": "https://mlchart.com/terminology/oncology/hemizygous/"
}