There are several medical illnesses that exhibit unusual clinical features. These diseases are rare and occur very less likely in a population. The signs and symptoms of such diseases are way different than of the commonly occurring diseases. Here are a few such diseases.

Fatal Familial Insomnia

This is Hayley and Lachlan Webb, siblings from Queensland have a rare disorder that prevents them from ever going to sleep and will ultimately kill them. As the name suggests, this disorder runs in families and is characterized by inability to sleep. Thalamus of the brain, which regulates sleep, is affected. The symptoms of insomnia are mild in the beginning but get worse with time. The person can later develop problems in the autonomic activity of the body causing abnormalities in blood pressure, breathing and heart rate. Dementia and problems in speech are also some of the symptoms of the disease.

Geographic Tongue

Also called as  Benign Migratory Glossitis. The disease affects the mucosa of the dorsal surface of the tongue. The surface of the tongue develops map like pattern which gives it the name of ‘Geographic’. The person feels burning sensation on the tongue. There is no evidence of the disease causing any malignant condition. The patches on the tongue change their shapes and position every now and then. Topical anesthetics can be used for symptoms. However, no permanent treatment is yet discovered.

Human Werewolf Syndrome

It is a disorder characterized by an abnormal growth of long hair on the whole body, hence the name Werewolf Syndrome. . The disorder can be there since birth or can occur later in life. There are several variants like Terminal hypertrichosis, Generalized hypertrichosis, Circumscribes hypertrichosis etc. The length of the hair in this disorder is longer than the normal length of body hair. The disorder is caused by a mutation in the genes of the body. People tend to opt for hair removal techniques, but the solution is only temporary.

Fibrodysplasia ossificans progressiva, “Stone Man Syndrome”

Also known as the Münchmeyer disease, Fibrodysplasia Ossificans Progressiva is disorder of the connective tissues that get calcified over time, forming bones. The cause id a genetic mutation which causes excessive bone formation. The bone formation accelerates after a trauma and causes immobility of joints, muscles and tendons. If the bone is removed by any procedure, the mechanism accumulates more bone, further aggravating the condition. The immobility of the facial muscles causes problems in eating speaking as well. The disease is autosomal dominant. There is no treatment for the condition yet.

Cold Urticaria, “Cold Allergy”

Cold Urticaria is allergy from cold. This means that a person who suffers from Cold Urticaria gets an allergic reaction on his/her body when exposed to cold. Hives are formed on the body are itchy. The situation can get worse and can involve pharynx and tongue, which might cause obstruction in breathing. The swelling and itch is due to the substance called Histamine that is released in response to cold stimulus. Antiallergic medications can be used for the condition.

Epidermodysplasia Verruciformis, Lewandowsky-Lutz dysplasia, “Tree Man Syndrome”

It is an Autosomal recessive condition characterized by Growth of macules and papules on the skin that resembles the bark of a tree, hence it is also known as the Treeman Syndrome. The causative organism is the Human Papilloma Virus. It is also called  Lewandowsky-Lutz dysplasia. The affected person develops macules and wart like papules on his body, mainly on the hands and feet. The warts are flat in the beginning and then develop into large tumor like lesions all over the body. The condition is caused by a genetic mutation. The treatment is symptomatic and temporary only.

Xeroderma Pigmentosum, “Vampire Syndrome”

The ultraviolet rays of the sun are harmful for all of us. However, they are even more dangerous in people who suffer from a disorder known as the Xeroderma Pigmentosum. It is a disorder that occurs due to mutations in genetic material. It leads to inability of the body’s mechanism to repair the damaged DNAs caused by the ultraviolet rays of the sun. Continuous damage with no repair causes several symptoms like excessive pigmentation on the sun exposed area, dryness, and severe sunburns. Children usually develop skin cancer by the age of 10. This is called the Vampire Syndrome because the people fear from going into the sun due to the damage it causes. Children with this disorder are called ‘Moon Children’

Elephantiasis 

It is a condition characterized by swelling of the soft tissues of the body, mainly involving genitals, lower limbs and breasts. The affected skin can also thicken, giving it an appearance of an elephant’s skin. It is also called the Lymphatic Filariasis, due to the involvement of lymphatic system which gets obstructed. The disease is more prevalent in tropical and subtropical areas and is spread by mosquitoes which are infected by the round worm larvae. The anti-parasitic medicine is used to treat the condition

Aquagenic urticaria, “Water Allergy”

It refers to a disorder in which the body shows an allergic-like response to water. The person affected develops rash and feels burning and itching on the skin, which gets exposed to water. Patient gets symptoms after exposure to rain, snow and even to body secretions like tears and sweat. Antihistamine help with the symptoms however, more aggressive drugs like adrenaline may be needed in cases of severe response. There are some evidences which state that the response is not due to but due to the presence of certain other compounds or elements in the water.

Exploding Head Syndrome

This is a disorder in which the person hears loud noises while sleeping or when waking up. The noises are disturbing and irritating which frustrates the affected individual. Some people also report visual flashes of light along with the noises. It can be classified into sleep disorder as it disturbs the person’s sleep. The quality of life of the affected person gets compromised as he/she is unable to sleep properly and stays tired and sleepy throughout the day. The exact cause is unknown, yet there maybe some contributing factors like stress and anxiety. There are a few medications that induce sleep however, counselling has also proved to help in this case.

Moebius Syndrome

It is a syndrome characterized by inability of a person to use their facial muscles. The affected person can’t smile, laugh, nod or swallow properly. Patient finds it difficult to move his/her eyes or even smile. There is weakness or either complete paralysis of the facial muscles. Children born with this syndrome usually have small mouth and chin and may also have a cleft palate.

Riley-Day Syndrome

Another name for this disease is Familial Dysautonomia. The disease is characterized by abnormality in sensory system of the body. The disease affects the autonomic system of the brain and the affected person experiences various signs and symptoms. Postural hypotension, inability to feel pain sensation, gastrointestinal motility problems, difficulty in swallowing and vomiting. The condition is autosomal recessive which means that both parents of the affected individual should have at least one gene of the disease.

Congenital Insensitivity to Pain

Also known as Congenital Analgesia, this disorder is present since birth. The affected people usually die in their childhood due to the damage in their bodies which remains unnoticed and gets worse. Unlike similar disorders, this disease has no other sensory abnormality. The children fail to indicate pain due to fractures or eye damage. This disease is due to a mutation in one of the genes and showed response to the drug named Naloxone.

Fish Odor Syndrome

Also known as the Trimethylaminuria. This is a disorder that is characterized by a rotten fish like smell from the affected individual. This smell comes from the person’s secretions like urine, breath and sweat. The cause is the absence of an enzyme that metabolizes a protein Trimethylamine. Another cause of the disorder is excessive production of Trimethylamine which has a fishy odor. The disorder is genetic and has no cure except for using fragrant substances to avoid the smell and avoiding the usage of food items that have or produce Trimethylamine