Llanelli (“St Elli‘s Parish“; Welsh pronunciation: [ɬaˈnɛɬi]) is the largest town in the county of Carmarthenshire and the preserved county of Dyfed, Wales. Located on the Loughor estuary, some 10 miles (16 km) north-west of Swansea and 12 miles (19 km) south-east of the county town, Carmarthen, Llanelli is famous for its rugby tradition and as a centre of tinplate production.  Several communities nearby the town are often included colloquially in Llanelli.

Fields’ disease is considered to be one of the rarest known diseases in the world, with only two diagnosed cases. The frequency of this disease is therefore 1 in approximately 3.75 billion (although since the disease manifested in identical twins, the actual frequency is 1 in approximately 7.5 billion).   It is named after Welsh twins Catherine and Kirstie Fields, of Llanelli. Fields’ disease is a neuromuscular disease, causing muscular degeneration.

The disease was first noticed when the twins were four. Doctors have been unable to identify it and have not been able to match it to any known diseases. As a result, the Fields sisters have undergone numerous tests, but no treatment has yet been found. No definitive cause has been determined, and doctors have generally concluded that they were born with it.

We’re definitely getting into the nitty-gritty of the world’s rarest diseases when we’re talking about Fields Condition, a progressive muscle disorder that affects two sisters (Kirstie & Catherine Fields) and can cause painful muscle spasms up to 100 times each day. The disease is still predominantly a mystery to doctors, but in its wake it’s paralyzed both sisters and cut off their ability to speak, with the two now relying on electronic speech machines to communicate.

The extent of this disease is still not very well known. This very disease has had not shown any effect on their brains or personalities up to now. There is still the uncertainty of not knowing that whether the disease is fatal or not or what is the life expectancy with this kind of disease. If the cause of this disease is considered to be somewhat genetic, then there are possibilities of the twins passing this disease to their offspring’s.

However, it is made clear that this disease is definitely not communicable. However, due to the rarity of this disease, there is still uncertainty and lack of any form or equipment for the cure of this disease.

Regarding the twins alive, the twins require the use of wheelchairs for mobility and are unable to speak without the assistance of electronic speaking aids. They experience persistent and painful muscle spasms which are worsened by emotional distress. They are currently living with their parents, with the assistance of hospice workers. Doctors continue to administer tests to the twins in search of a treatment.

At this point this is all we know about the fields’ disease as the doctors are still researching on it and have not been able to find much on it.