Iron deficiency warning: Could YOU spot symptoms of these three RARE diseases?

Most people are aware of some of the symptoms of the leading killers in the UK - dementia, heart disease and pneumonia.

But there are thousands of lesser known conditions that can have an equally deadly effect if not spotted in time.

A rare disease is defined by the European Union as one that affects fewer than 5 in 10,000 of the general population, according to Rare Disease UK.

There are between 6,000 and 8,000 diseases currently known, but around five new diseases are discussed in medical literature each week.

In the UK, a rare disease may affect a single person or up to 30,000 people.

Charlie Gard was one of only 16 people in existence known to have suffered from mitochondrial depletion syndrome.

Here are three unusual rare diseases and their symptoms.

Alice in Wonderland syndrome

The neurological condition - also called Todd’s syndrome - affects visual perception.

Sufferers feel as if their surroundings - or even their own body parts - are growing or shrinking, and they may also experience a migraine.

Episodes are usually short and can occur up to several times in a day.

It is named after Lewis Caroll’s Alice's Adventures in Wonderland - the title character experienced similar symptoms.

Tongue cancer

It is known as squamous cell cancer of the oral tongue if it develops at the front of the tongue, and squamous cell cancer at the base of the tongue if it develops in the rear third.

Oral cancers represent only three per cent of all cancers, according to the National Organisation for Rare Disorders.

Symptoms for the oral tongue type include a pinkish-red sore at the side of the tongue that bleeds easily.

Signs for the base of the tongue type include pain in the tongue and surrounding tissue, changes in voice tones and sounds, and difficulty in swallowing that may lead to feelings of bloat or fullness.

It is most common in men over 60 years.

Pica syndrome

This syndrome is where sufferers develop an appetite for everything, even if items aren’t edible and have no nutritional value.

Sufferers have been known to develop a desire for sand, buttons, hair, chalk, clay, raw rice, plaster, flour and dirt.

The condition can become concerning if they consume a particularly dangerous item, like paint or faeces.

It is thought that deficiencies in iron, zinc, or another nutrient could be a cause.