Another less common verbal response in the United States and Canada to anothers sneeze is "Gesundheit", which is a German word that means, appropriately, "good health". Several hypotheses exist for why the custom arose of saying "bless you" or "God bless you" in the context of sneezing:

Some say it came into use during the plague pandemics of the 14th century. Blessing the individual after showing such a symptom was thought to prevent possible impending death due to the lethal disease. In Renaissance times, a superstition was formed claiming ones heart stopped for a very brief moment during the sneeze; saying bless you was a sign of prayer that the heart would not fail. It has also been stated that one says "(God) bless you" so that one does not catch the flu, cold, or any other forms of sickness.Other cultures have similar traditions:

In China, after a person sneezes they often say "百岁!" which translates to "may you live one hundred years!" the pronunciation is similar to "bless you" in English. pronunciation: [Bai Sui]
In Iran, it is common to respond to sneezing with the Persian phrase عافیت باشه âfiyat bâše, which translates to "health", similar to common European expressions. Indian culture is to respond with Krishna, similar to a blessing in western cultures. In Italy after a person sneezes the people present respond with the word "salute" (meaning: health). The louder the sneeze the more emphatic the response. In Slovakia, after a person sneezes, it is proper to say "Na zdravie!" which means "For health!
Distal spinal muscular atrophy type 1 (DSMA1), also known as spinal muscular atrophy with respiratory distress type 1 (SMARD1), is a rare neuromuscular disorder involving death of motor neurons in the spinal cord which leads to a generalised progressive atrophy of body muscles. The condition is caused by a genetic mutation in the IGHMBP2 gene and is inherited in an autosomal recessive manner. There is no known cure to DSMA1, and research of the disorder is still in early stages due to low incidence and high mortality rates. Signs and symptoms
Usually, the first respiratory symptoms are shortness of breath (dyspnea) and paradoxical respirations which then escalate within the first few months of life to diaphragmatic paralysis. The symptoms of diaphragmatic paralysis come on very rapidly and without warning, and the patient is often rushed to a hospital where they are placed on a ventilator for respiratory support. Due to the severe nature of diaphragmatic paralysis, the patient eventually needs continuous ventilation support to survive. Continuous ventilation, however, may in itself cause damage to the anatomy of the lungs.In addition to diaphragmatic paralysis, other issues may arise: as the name suggests, the distal limbs are most affected with symptoms of weakness, restricting mobility due to (near-)paralysis of the distal limbs as well as the head and neck. Also, dysfunction of the peripheral nerves and the autonomic nervous system may occur. Due to these dysfunctions, the patients have been shown to suffer from excessive sweating and irregular heartbeat.