Late infantile variant usually manifests between 2 and 4 years of age with seizures and deterioration of vision. The maximum age before death for late infantile variant is 10–12 years. Juvenile NCL (JNCL, Batten disease, or Spielmeyer-Vogt), with a prevalence of one in 100,000, usually arises between 4 and 10 years of age; the first symptoms include considerable vision loss due to retinal dystrophy, with seizures, psychological degeneration, and eventual death in the mid- to late 20s or 30s ensuing. Adult variant NCL (ANCL or Kufs disease) is less understood and generally manifests milder symptoms; however, while symptoms typically appear around 30 years of age, death usually occurs 10 years later.All the mutations that have been associated with this disease have been linked to genes involved with the neural synapses metabolism – most commonly with the reuse of vesicle proteins. Genetics
Childhood NCLs are generally autosomal recessive disorders; that is, they occur only when a child inherits two copies of the defective gene, one from each parent. When both parents carry one defective gene, each of their children faces a one in four chance of developing NCL. At the same time, each child also faces a one in two chance of inheriting just one copy of the defective gene. Individuals who have only one defective gene are known as carriers, meaning they do not develop the disease, but they can pass the gene on to their own children.
These deposits take on characteristic shapes, depending on the variant under which they are said to occur: granular osmophilic deposits (GRODs) are generally characteristic of INCL, while curvilinear profiles, fingerprint profiles, and mixed-type inclusions are typically found in LINCL, JNCL, and ANCL, respectively. Electroencephalogram or EEG: An EEG uses special patches placed on the scalp to record electrical currents inside the brain. This helps doctors see telltale patterns in the brains electrical activity that suggest a patient has seizures. Electrical studies of the eyes: These tests, which include visual-evoked responses and electroretinograms, can detect various eye problems common in childhood NCLs. Brain scans: Imaging can help doctors look for changes in the brains appearance. The most commonly used imaging technique is computed tomography (CT), which uses x-rays and a computer to create a sophisticated picture of the brains tissues and structures. A CT scan may reveal brain areas that are decaying in NCL patients. An increasingly common tool is magnetic resonance imaging, which uses a combination of magnetic fields and radio waves, instead of radiation, to create a picture of the brain. Enzyme assay: A recent development in diagnosis of NCL is the use of enzyme assays that look for specific missing lysosomal enzymes for infantile and late infantile versions only. This is a quick and easy diagnostic test.