Batten Disease (Neuronal Ceroid Lipofuscinosis)
The onset of the nervous system disorder known as Batten disease is caused by the inheritance of faulty genetic matter from both parents. While it can take years to manifest itself it is typically diagnosed during childhood. As it stands there is no cure for Batten Disease and it remains one of today's modern medical mysteries. We know the cause, can pinpoint the gene but there is no preventative vaccine and once diagnosed premature death is the inevitable outcome.
The quality of life of those who suffer from Battens Disease will deteriorate at an alarming rate and early symptoms are commonly misdiagnosed. The earliest symptoms usually present themselves in children between the ages of 5 – 10 years old. Parents may notice that their child is developing problems with their vision or starting to suffer from seizures. These early signs are often very subtle and take the form of changes in personality and/or behaviour, clumsiness or slow learning.
As the disease progresses these children will suffer from cognitive impairment, worsening of their seizures and a progressive loss of their motor skills and sight. Eventually, they will become bedridden, blind and suffer from extreme dementia. Such is the severity of Batten Disease few children will survive past their teens or early twenties.
How It Came to be Called Batten Disease
The name Batten Disease comes from the British Paediatrician Dr Frederick Batten who first recorded the disorder in 1903. It is also known by the name of Spielmeyer-Vogt-Sjogren-Batten disease and is the most common of the group of disorders known as NCL's; neuronal ceroid lipofuscinoses. Originally, Batten disease specifically referred to JNCL, NCL's junior form but is now the term generally used by paediatricians to describe every form of NCL.
Whilst commonly referred to as Batten Disease, NCL's actually denote several neurodegenerative disorders which are both genetic and life limiting. These disorders all share similar features thus they all come under the umbrella of NCL. Although Dr Frederick Batten first saw the disease in 1903 it wasn't until the 20th century, 1995 to be exact, that the first genes which caused NCL were discovered and identified. In the 20 years since 13 different genes with more than 400 mutations between them have been identified as causing the different forms of NCL.
Forms of NCL
NCL takes on four main forms; three types which appear in childhood and a very rare type which affects adults. The symptoms of the childhood forms are similar to those of Batten Disease but become apparent as various ages and the progression rates will differ.
Congenital NCL is a rare and extremely severe form affecting newborns. Babies will suffer from microcephaly, unusually small heads, suffer seizures and will survive for only a short time after birth.
INCL, also known as Infantile NCL or Santavuori-Haltia disease, presents itself between the ages of 6 months and 2 years and carries a rapid rate of progression. Children affected by INCL will fail to thrive and also suffer from microcephaly. Other typical manifestations are short and sharp muscle contractions known as myoclonic jerks. Children suffering from INCL will rarely live past 5 years of age, although some have been reported to survive for a few more years, albeit in a vegetative state.
LINC, Late Infantile NCL or Jansky-Bielschowsky typically begins between the ages of 2 and 4. Early signs include ataxia, the loss of coordination of the muscles, and severe seizures which don't respond to medication. This is another form with a rapid rate of progression and death usually occurs between the ages of 8-12.
Adult NCL, also known as Kufs disease and Parry's disease, will usually begin before the age of 40. This strain has milder symptoms and a slow progression rate. Blindness is not a side effect of ANCL but it invariably shortens life expectancy.
How NCL is Inherited
The majority of NCL disorders are inherited through a faulty “autosomal recessive” gene. Both parents will have this gene and the sex of the child plays no part in whether they will develop the disease or not. As the parents carry only one faulty gene each they are carriers, only children with two abnormal genes could potentially develop Batten Disease.
The Chances of Inheriting Batten Disease
Any child born to those parents who are both carrying the faulty gene with an autosomal recessive mutation has a 1 in 4 chance of inheriting those malfunctioning and abnormal genes from both of their parents and therefore developing one of the forms of Batten Disease. Their chances of inheriting one of the abnormal genes is 50% chance, thus making them a carrier but not being actually affected by the disease. There is also a 25% chance of a child being born without either abnormal gene and therefore being neither affected by the disease nor a carrier.
When both parents are known to carry the abnormal gene their offspring are considered to have a 2 in 3 chance of being a carrier. This figure is only prevalent when it has been established that they don't indeed have the disease. During any pregnancy the probability of that child inheriting either or both genes is the same, irrespective of the status of any siblings.
Current statistics for British Sufferers
It is estimated that approximately between 1 and 3 children are diagnosed each year with one of the infantile forms of the disease. This means that there are likely to be 15-30 children currently suffering from Batten Disease in the UK. The estimate for children diagnosed with LINCL, including its variants, each year is between 7 and 10. Meaning that there is probably between 30-60 children and young people currently affected in the UK.
The estimated number of children diagnosed each year with one of the juvenile forms of the disease is 3-4, so there could be around 30-40 current sufferers in the UK. Adult NCL is too rare to provide any solid statistics although affected individuals have been clinically identified in several different countries.
In short, the estimated number of adults, young people and children currently living in the UK who have been diagnosed with an NCL is 100-150.
Progression of the Disease
Every genetic variant brings its own rate of progression. Increasing visual impairment will result in total blindness, seizures will progress to severe epilepsy which stops responding to medication, rapid and involuntary muscle spasms of the limbs will occur, sleep problems will develop, swallowing, speech and language skills will decline and all motor skills will cease to exist leaving the sufferer bedridden. The suffer will eventually become completely dependent on their families and carers for all of their everyday needs. Premature death is inevitable and can occur at anytime from early childhood up to early adulthood. This is impossible to predict without knowing the age when the disease presented itself and the diagnosis of which specific gene is at fault.
Treatment and Research
There is currently no cure for any form of NCL but therapy and specialist symptom management is available to maintain a good quality of life for as long as possible. Much needed support for families of sufferers is also available and highly recommended.
Limited funds are being made available for research into NCL's but nevertheless it is continuing. Possible methods of slowing the disease's progression and potential cures are being researched by a small number of scientists and doctors.