Any genetic disorder caused by a change affecting only one gene.
There are thousands of single-gene diseases including achondroplasia, cystic fibrosis, hemophilia, Huntington disease, muscular dystrophy, and sickle cell disease .
Single-gene diseases usually follow simple Mendelian patterns of inheritance — autosomal dominant, an autosomal recessive, or an X-linked.
Single gene diseases are as opposed to polygenic diseases which are caused by a combination of two or more genes.
- Single nucleotide polymorphism
A change in which a single base in the DNA differs from the usual base at that position. Abbreviated SNP and pronounced snip. Millions of SNP’s have been cataloged in the human genome. Some SNPs are responsible for disease such as the SNP responsible for sickle cell disease. Many other SNPs are normal variations in […]
- Single palmar flexion crease
Simian crease. Single upper palm crease Single transverse palmar line Four-finger line Single palmar flexion line Single upper palm line
Term used to described a study in which either the investigator or the participant, but not both of them, is unaware of the nature of the treatment the participant is receiving. Also called single-masked.
- Single-payer health care
A system of health care characterized by universal and comprehensive coverage. Single-payer health care is similar to the health services provided by Medicare in the US. The government pays for care that is delivered in the private (mostly not-for-profit) sector. Doctors are in private practice and are paid on a fee-for-service basis from government funds. […]
- Sinoatrial node
The heart’s natural pacemaker, one of the major elements in the cardiac conduction system, the system that controls the heart rate. Abbreviated SA node. The SA node consists of a cluster of cells that are situated in the upper part of the wall of the heart’s right atrium, where the electrical impulses are generated. An […]