The McMredie-McBride hypothesis explains that the limbs of the infants become malformed as a result of the thalidomide harming the neural tissue—simply because the neural tissue has such a large impact on formation and development of the limbs. Causes
Thalidomide
Thalidomide was released onto the market in 1958 in West Germany under the name Contergan. Primarily prescribed as a sedative or hypnotic, thalidomide also claimed to cure "anxiety, insomnia, gastritis, and tension". Afterwards it was used against nausea and to alleviate morning sickness in pregnant women. Thalidomide became an over-the-counter drug in Germany around 1960, i.e. it could be bought without a prescription. Shortly after the drug was sold, in Germany between 5,000 and 7,000 infants were born with phocomelia. Only 40% of these children survived.Research also proves that although phocomelia did exist through the 1940s and 1950s cases of severe phocomelia multiplied in the 1960s when thalidomide was released in Germany; the direct cause was traced to thalidomide. The statistic was given that "50 percent of the mothers with deformed children had taken thalidomide during the first trimester of pregnancy." Throughout Europe, Australia and the United States 10,000 cases were reported of infants with phocomelia; only 50% of the 10,000 survived. Thalidomide became effectively linked to death or severe disabilities among babies. Those subjected to thalidomide while in the womb experienced limb deficiencies in that the long limbs either were not developed or presented themselves as stumps. Other effects included deformed eyes, hearts, alimentary and urinary tracts, blindness and deafness.
Genetic inheritance
According to National Organization for Rare Disorders (NORD): when phocomelia is transmitted [in its familial genetic form] it is seen as an autosomal recessive trait and the mutation is linked to chromosome 8.A study of Roberts Syndrome, a genetic disorder showing similar symptoms to phocomelia, has shed light on the possible causes. An individual afflicted with Roberts Syndrome will have chromosome copies that do not connect at the centromeres, making them unable to line up accordingly. As a result, the newly made cells contain an excess or reduced number of chromosomes. In both Roberts Syndrome and phocomelia the cells cease to develop, or die, preventing proper development of the limbs, eyes, brain, palate, or other structures. Treatment
Prosthesis is a synthetic alternative for missing limbs, teeth, and various other body parts. Advances in prosthetic limbs have increased greatly during the twentieth century. The use of new materials such as modern plastics, complex procedures and better pigments have created lighter in weight and more realistic looking artificial limbs. With the advancement of myoelectric prosthetic limbs, patients are able to move their limbs without the use of cords or other devices. The myoelectric limbs can detect electric signals from the nervous system and muscles. They were first used on adults, but now they are being fitted to children.Patients that receive a loss of limbs due to phocomelia are typically treated with prosthetics. Infants at the age of six months are recommended to have a prosthetic mitten fitted; enabling them to get used to the prosthesis.