What are some diseases caused by a deficiency of water?

According to Healthy Place, a persistent deficiency of water can cause depression; chronic fatigue syndrome; insulin-dependent diabetes; lupus; multiple sclerosis; muscular dystrophy; amyotrophic lateral sclerosis, or ALS, otherwise known as Lou Gehrig's disease; Parkinson's disease; and Alzheimer's disease. A deficiency of water is also known as dehydration.

According to the Mayo Clinic, severe dehydration can lead to heat injury, from cramps to heat stroke; swelling of the brain; seizures; low blood pressure; shock caused by low blood volume; kidney failure; coma; and death. A doctor can perform blood tests and urinalysis to determine if a patient is suffering from dehydration.