Monosomy is the state of having a single copy of a chromosome pair instead of the usual two copies found in diploid cells. Monosomy can be partial if a portion of the second chromosome copy is present. Monosomy, or partial monosomy, is the cause of some human diseases such as Turner syndrome and Cri du Chat syndrome.
To play the media you will need to either update your browser to a recent version or update your Flash plugin
Monosomy is used to refer to a status of an autosomal gene, when normally two copies are supposed to be present and instead only a single copy of a gene is present. This word can also refer to multiple genes or segments, or even an entire chromosome, where an individual is supposed to have two copies of this gene or chromosome, and they only have a single copy. The loss of one of two copies of an autosomal gene or segment of genes, or an entire chromosome, is a cause of human genetic disease.
Leslie G. Biesecker, M.D.
Chief and Senior Investigator, Genetic Disease Research Branch; Head, Human Development Section and Physician Scientist Development Program
Dr. Biesecker's research focuses on the clinical and molecular delineation of human malformation syndromes. Currently, his laboratory is working on two classes of disorders, classic multiple congenital anomaly syndromes and segmental overgrowth disorders. The goals of his research program are to improve the medical care of patients affected by these disorders, provide generalized knowledge about the broad field of birth defects, and better understand basic mechanisms of normal and abnormal human development. Dr. Biesecker's group studies several multiple congenital anomaly syndromes, including Pallister-Hall syndrome, McKusick-Kaufman syndrome, Bardet-Biedl syndrome and Lenz microphthalmia syndrome.