27 Rare and Mysterious Medical Conditions

A parasitic twin is also called an asymmetrical twin or unequal conjoined twin. The twin has stopped developing during the gestation period of a pregnancy but remains physically attached to the developing twin. The fully developed twin is later born with limbs or other organs still attached and a surgery is needed to remove it. What triggers the deformity is unclear and there are no symptoms. There have been fewer than 200 cases of a parasitic twin ever reported.

Pica is a mental health condition and eating disorder characterized by compulsively eating and swallowing non-food items, such as ice, hair, chalk, or soap. The most common causes of Pica, which is thought of as the body’s way to correct a nutrient deficiency, are anemia and malnutrition. Pica is not considered dangerous, though that depends on what item a person is trying to swallow.

Proteus Syndrome is a very rare genetic condition characterized by an excessive growth of bones, skin, organs or other parts of the body. Though any part of the body can be affected, the most common ones are bones in the limbs, skull, and spine. Proteus syndrome, which is not inherited and can arise randomly during prenatal development stages, is extremely rare with only a few hundred cases ever reported and an incidence of less than one in a million.

Rapunzel Syndrome is not a hair problem per se; it is a very rare intestinal condition – usually among girls and young women – that results when a person ingests hair, which gets stuck in the stomach. The condition often goes undetected for years as there are no symptoms for a long time. By the time symptoms – usually bloating, nausea, feeling full, and vomiting – are observed, the hair ball is large and surgery is needed to remove it.

As the nickname for this very rare metabolic disorder may suggest, it is a condition that causes a person’s sweat, breath, and urine to smell like fish. There is no cure for it but the unpleasant fishy odor can be controlled with changes in diet and the use of certain soaps and lotions. Though some people with the condition, which is more common among women, inherit the defective genes that cause it, others develop it after taking certain medications.