FD - familial dysautonomia, also known as Riley-Day Syndrome and HSAN type III.
 
Familial dysautonomia (FD) is a rare genetic disease that affects the autonomic and sensory nervous systems of children from birth. The most striking symptoms of FD are reduced sensitivity to pain and temperature, and the inability to produce tears. But FD is much more than “no pain and no tears,” it affects every major system of the body, causing severe respiratory, cardiovascular, orthopedic, digestive, renal and vision problems.    
 
Children with FD lack the most basic reflexes and instincts that we take for granted. As a result, their bodies cannot function normally. They cannot control their blood pressure or heart rate, and they lack the ability to suck at birth and the ability to swallow properly. Because they often swallow into their lungs rather than their stomachs, they are prone to pneumonia.  As a result, most FD patients have a feeding tube, so they can be fed directly into their stomachs and reduce the risk of pneumonia.    
 
FD was once thought of as a fatal childhood disease, with most children expected to live, on average, only to five years of age. Advances in treatment have dramatically extended life expectancy, but children with FD still suffer from chronic and often debilitating symptoms that prevent them from leading normal lives.  FD causes a mysterious syndrome called “autonomic crisis” in which patients experience extreme swings in blood pressure and heart rate, along with dramatic personality changes, and a complete shut down of the digestive system. Once FD patients go into crisis, they cannot engage in any normal activity until hours or days later, and they may require hospitalization for observation, sedation and hydration until the crisis abates.