Today Is...Rare Disease Day

According to the NHS website, rare diseases are the ones that impact very few people out of the general population and most don't even have proper treatment and they give a brief the top 10 rarest known. 
The most rarest is RPI Deficiency which is considered to be the rarest disease in the world. Ribose-5-Phosphate Isomerase (RPI), is a crucial enzyme in a metabolic process in the human body which causes muscle stiffness, seizures and a reduction of white matter in the brain. There has only ever been one case and that was in 1984 and since then there have been no cases.
Field’s disease has only ever affected two people and they were twin sisters who suffered a degeneration of their muscles and weakening of the body. Medical experts are still researching the condition.
Hutchinson-Gilford Progeria Syndrome (HGPS) affects 1 in 20 million people and causes premature ageing and makes even 2-year-olds look aged and weak. There is no current cure for HGPS at the moment.
Methemoglobemin is a form of haemoglobin that makes our blood, skin, lips and nails turn blue in color. It can be inherited but MetHb usually happens when people use certain medications or recreational drugs or exposure to certain chemicals.
Aquagenic Urticaria is a Water Allergy where a person’s skin turns red and itchy after overexposure to water. People suffering from this condition can also be allergic to snow, sweat, and rain.
Foreign Accent Syndrome causes a person to speak in a different accent from their natural one and the main cause of Foreign Accent Syndrome is a brain injury.
Lesch–Nyhan Syndrome is a male only neurological disability which causes people to behave aggressively and harm themselves through head hitting and hand biting due to too much Uric Acid in the body and affects 1 in 3 million men.
Kuru Disease is named as it only affects the Kuru tribe in Papua New Guinea who consume the tissues of their loved ones after their death including the Brain which causes the transmission of prion- an infectious protein.
Harlequin is a disease which makes skin looks like fish scales and makes the body incapable of maintain proper temperature. There is no known cure.
Stone Man’s Disease transforms a person’s muscle tissues into bones.