Soil water status as a function of pressure (tension). Soil water status in natural soils can range from a flooded. condition to drainable gravitational water to plant available water. down to hydroscopic water. Tensions in natural soils do not. exceed -31,000; in this range, water is absorbed from the air.
Advanced Search. Tay-Sachs disease (the most severe form of Hexosaminidase A deficiency) is a progressive, fatal genetic condition that affects the nerve cells in the brain.
Back to Top Causes. Tay-Sachs disease occurs when the body lacks hexosaminidase A, a protein that helps break down a chemical found in nerve tissue called gangliosides. Without this protein, gangliosides, particularly ganglioside GM2, build up in cells, especially nerve cells in the brain.Tay-Sachs disease is caused by a defective gene on chromosome 15. When both parents carry the defective Tay-Sachs gene, a child has a 25% chance of developing the disease.The child must receive two copies of the defective gene -- one from each parent -- in order to become sick.ithout this protein, gangliosides, particularly ganglioside GM2, build up in cells, especially nerve cells in the brain. Tay-Sachs disease is caused by a defective gene on chromosome 15. When both parents carry the defective Tay-Sachs gene, a child has a 25% chance of developing the disease.