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.
A defective gene on chromosome 15 (HEX-A) causes Tay-Sachs disease. This defective gene causes the body to not make a protein called hexosaminidase A. Without this protein, chemicals called gangliosides build up in nerve cells in the brain, destroying brain cells. The disease is hereditary, which means it is passed down through families.