There are three types of genetic disorders: 1  Single-gene disorders, where a mutation affects one gene. Sickle cell anemia is an example. 2  Chromosomal disorders, where chromosomes (or parts of chromosomes) are missing or changed. Chromosomes are the structures that hold our genes. 3  Complex disorders, where there are mutations in two or more genes.
OSI model. The Open Systems Interconnection model (OSI model) is a conceptual model that characterizes and standardizes the communication functions of a telecommunication or computing system without regard to their underlying internal structure and technology. Its goal is the interoperability of diverse communication systems with standard protocols.
Knowledge center. Obstructive sleep apnea, also known as OSA, is a sleep disorder in which the person stops breathing for at least 10 seconds each hour during sleep. It is caused by relaxation of the throat muscles; the soft tissue in the back of the throat collapses and closes, resulting in blocked airways.