Conjoined twins – sometimes popularly referred to as Siamese twins – are twins joined in utero. A very rare phenomenon, the occurrence is estimated to range from 1 in 49,000 births to 1 in 189,000 births, with a somewhat higher incidence in Southwest Asia and Africa. Approximately half are stillborn, and an additional one-third die within 24 hours. Most live births are female, with a ratio of 3:1.Two theories exist to explain the origins of conjoined twins. The more generally accepted theory is fission, in which the fertilized egg splits partially. The other theory, no longer believed to be the basis of conjoined twinning, is fusion, in which a fertilized egg completely separates, but stem cells (which search for similar cells) find similar stem cells on the other twin and fuse the twins together. Conjoined twins share a single common chorion, placenta, and amniotic sac, although these characteristics are not exclusive to conjoined twins, as there are some monozygotic but non-conjoined twins who also share these structures in utero.Chang and Eng Bunker (1811–1874) were brothers born in Siam (now Thailand) who traveled widely for many years and were labeled as The Siamese Twins. Chang and Eng were joined at the torso by a band of flesh, cartilage, and their fused livers. In modern times, they could have been easily separated. Due to the brothers fame and the rarity of the condition, the term "Siamese twins" came to be associated with conjoined twins. Causes
There are two theories about the development of conjoined twins.
The patient also lacks the ability to cough and therefore must undergo a treatment to shake up their body to remove the mucus from the lining of their lungs. Medication is also given to patients to lessen their symptoms including seizures.Currently the government is testing several treatments including N-butyl-deoxynojirimycin in mice, as well as stem cell treatment in humans and other medical treatments recruiting test patients. A Sandhoff disease study showing proof of principle for gene therapy in a human model system using CRISPR and virus gene correction gives the chance for clinical trials to cure the disease. The ultra-rare occurrence is a main hurdle to overcome for clinical trials. History
Sandhoff disease is one of several forms of what was formerly known as amaurotic idiocy. This inherited disease is characterized by the accumulation of lipid-containing cells in the viscera and in the nervous system, mental retardation, and impaired vision or blindness. The chemical and enzymatic analysis of various patients with amaurotic idiocy by Konrad Sandhoff (1939- ), a German biochemist, led to the identification of several biochemically distinct diseases: The first biochemical description of GM1-gangliosidosis in 1963, Sandhoff disease in 1968, Tay-Sachs-Disease, the AB-variant of GM2-Gangliosidosis and the B1-variant of GM2-gangliosidosis.The molecular defect in Sandhoff disease was discovered when Konrad Sandhoff studied the biochemistry of sphingolipids and gangliosides in the laboratory of Prof. Horst Jatzkewitz (1912–2002), a German biochemist (Max- Planck-Institute for Psychiatry, Munich). In October 1966, he obtained deep-frozen autopsy material from an infantile case with amaurotic idiocy.