27 Rare and Mysterious Medical Conditions

Hypertrichosis is an extremely rare condition that tends to run in families. It is defined as excessive hair growth anywhere on the body in men or women and can develop at any point in life. Scientists think that for people born with hypertrichosis, the inactive genes that caused excessive hair in humans living millions of years ago get reactivated in the womb for an unknown reason. Hypertrichosis that develops later in life may be due to malnutrition, poor diet, cell mutation, or certain skin diseases.

Methemoglobinemia, or MetHb, is a very rare blood disorder in which little oxygen is delivered to cells throughout the body. In those who have it, red blood cells contain methemoglobin, a form of hemoglobin that can’t carry oxygen, at levels higher than 1%. People are either born with it or can develop it later in life after exposure to certain drugs or chemicals. Most people with the condition have no symptoms in which case treatment may not be required. Severe cases may need blood transfusion.

Mirror-Touch Synesthesia (MTS) is a rare neurological condition in which a person feels sensations when seeing someone else being touched – similar sensations in the same or opposite part of the body. This usually means that a person feels pain when he or she sees someone else getting hurt. What causes MTS, which affects between 2% and 4% of people, is unclear.

Moebius Syndrome is a very rare birth defect – a neurological disorder characterized by the absence or underdevelopment of the nerves that control eye movements and facial expression. What causes the paralysis, which may affect as many as one in 50,000 people, is unclear but some research suggests it may be linked to genetic and environmental factors. People affected by the condition are usually unable to smile, raise their eyebrows, or even close their eyelids.

Munchmeyer’s Disease is a very rare genetic condition characterized by congenital malformations of the toes. Sporadic and painful flare ups eventually cause muscles, tendons, and ligaments to turn to bone. By the time a patient has reached early adulthood, he or she is completely immobilized. People with the disease live to about 55 years old, though most of their lives are spent in a wheelchair.