These mutations have included single base insertions and deletions, splice phase mutations, missense mutations, and other more complex patterns. Each of these mutations alters the genes protein product (i.e., the enzyme), sometimes severely inhibiting its function. In recent years, population studies and pedigree analysis have shown how such mutations arise and spread within small founder populations. Initial research focused on several such founder populations:

Ashkenazi Jews. A four base pair insertion in exon 11 (1278insTATC) results in an altered reading frame for the HEXA gene. This mutation is the most prevalent mutation in the Ashkenazi Jewish population, and leads to the infantile form of Tay–Sachs disease. Cajuns. The same 1278insTATC mutation found among Ashkenazi Jews occurs in the Cajun population of southern Louisiana. Researchers have traced the ancestry of carriers from Louisiana families back to a single founder couple – not known to be Jewish – who lived in France in the 18th century. French Canadians. Two mutations, unrelated to the Ashkenazi/Cajun mutation, are absent in France but common among certain French-Canadian communities living in southeastern Quebec and Acadians from the Province of New Brunswick. Pedigree analysis suggests the mutations were uncommon before the late 17th century.In the 1960s and early 1970s, when the biochemical basis of Tay–Sachs disease was first becoming known, no mutations had been sequenced directly for genetic diseases. Researchers of that era did not yet know how common polymorphisms would prove to be.
So, a descent from the surface to 10 metres (33 feet) underwater results in a doubling of the pressure on the diver. This pressure change will reduce the volume of a flexible gas-filled space by half. Boyles law describes the relationship between the volume of the gas space and the pressure in the gas.Barotraumas of descent are caused by preventing the free change of volume of the gas in a closed space in contact with the diver, resulting in a pressure difference between the tissues and the gas space, and the unbalanced force due to this pressure difference causes deformation of the tissues resulting in cell rupture.Barotraumas of ascent are also caused when the free change of volume of the gas in a closed space in contact with the diver is prevented. In this case the pressure difference causes a resultant tension in the surrounding tissues which exceeds their tensile strength. Use of a hyperbaric chamber
Patients undergoing hyperbaric oxygen therapy must equalize their ears to avoid barotrauma. High risk of otic barotrauma is associated with unconscious patients. Rapid decompression of a pressurised artificial environment
Explosive decompression of a hyperbaric environment can produce severe barotrauma, followed by severe decompression bubble formation and other related injury. The Byford Dolphin incident is an example. Rapid uncontrolled decomression from caissons, airlocks, pressurised aircraft, spacecraft, and pressure suits can have similar effects of decompression barotrauma. Rapid pressurisation of an artificial environment
Collapse of a pressure resistant structure such as a submarine, submersible, or atmospheric diving suit can cause rapid compression barotrauma.