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Batten disease is a fatal disease of the nervous system that typically begins in childhood. Onset of symptoms is usually between 5 and 10 years of age. Often it is autosomal recessive. It is the most common form of a group of disorders called the neuronal ceroid lipofuscinoses (NCLs).

Although Batten disease is usually regarded as the juvenile form of NCL (or "type 3"), some physicians use the term Batten disease to describe all forms of NCL. Historically, the NCLs were classified by age of disease onset as infantile NCL (INCL), late infantile NCL (LINCL), juvenile NCL (JNCL) or adult NCL (ANCL). At least 20 genes have been identified in association with Batten disease, but juvenile NCL, the most prevalent form of Batten disease, has been linked to mutations in the CLN3 gene. More recently, Batten disease has been classified based on the type of genetic mutation as CLN1 to CLN14.

It was first described in 1903.

Signs and symptoms[edit]
Early signs and symptoms of the disorder usually appear around ages 2–10, with gradual onset of vision problems, or seizures. Early signs may be subtle personality and behavior changes, slow learning or regression, repetitive speech or echolalia, clumsiness, or stumbling. Slowing head growth in the infantile form, poor circulation in lower extremities (legs and feet), decreased body fat and muscle mass, curvature of the spine, hyperventilation and/or breath-holding spells, teeth grinding, and constipation may occur.

Over time, affected children suffer mental impairment, worsening seizures, and progressive loss of sight, speech, and motor skills. Batten disease is a terminal disease; life expectancy varies depending on the type or variation.

Females with juvenile Batten disease show first symptoms a year later than males, but on average die a year sooner. However, the symptoms observed in female patients are more severe and progress at a faster rate compared to male patients.

Cause[edit]
NCLs are a family of diseases which are inherited in an autosomal recessive manner. Collectively referred to as Batten disease, NCLs are responsible for the majority of neurodegenerative diseases that affect children. Specifically, the frequency of this disease is about one per 12,500 individuals. The specific type of NCL is characterized by the age of symptomatic onset and genetic mutation involved. Currently, mutations in 14 genes lead to the development of Batten disease. Batten disease has an autosomal recessive pattern of inheritance.

NCL diseases[edit]

 * Infantile neuronal ceroid (INCL): CLN1 encodes for the protein PPT1 which functions as a lysosomal enzyme.
 * Late infantile NCL (LINCL): CLN2 encodes for the protein TPP1 which serves as a lysosomal enzyme. Life expectancy is between eight and twelve years of age.
 * Juvenile NCL (JNCL): CLN3 encodes for CLN3, a lysosomal transmembrane protein.
 * Adult NCL: CLN4 has no known associated protein.
 * Finnish variant of late infantile NCL (fLINCL): CLN5 encodes for CLN5, a soluble lysosomal protein.
 * Variant of the late infantile NCL: CLN6 encodes for the protein CLN6, which serves as a transmembrane protein of the endoplasmic reticulum.
 * Turkish variant of late infantile NCL: CLN7 or MFSD8, encodes for MFSD8, which functions as a lysosomal transmembrane protein.
 * Northern epilepsy: CLN8 encodes for CLN8, a transmembrane protein of the endoplasmic reticulum.
 * Late infantile NCL: CLN10 or CTSD encodes for CTSD, which is a lysosomal protein which a variety of functions.

Juvenile NCL: CLN3 mutation[edit]
The CLN3 gene is located on the short arm of chromosome 16 at gene position 12.1 (16p12.1), and mutations within this gene are the major cause of juvenile NCL. More specifically, 73% of Batten disease cases are due to a 1.02-kb deletion within this gene, CLN3, which causes a frame shift which produces a truncated mutant gene product of only 181 amino acids in length when compared to the wild-type gene product of 438 amino acids in length. Normal-functioning CLN3 encodes for a hydrophobic transmembrane protein that is mainly localized to the lysosome; however, the 181 amino acid mutant gene product was instead found to primarily localize to the endoplasmic reticulum and Golgi apparatus. The precise function of the CLN3 gene product remains unknown.