Incidence can vary greatly from type-to-type, and from country-to-country.

In Germany, one study reported an incidence of 1.28 per 100,000.

A study in Italy reported an incidence of 0.56 per 100,000.

A study in Norway reported an incidence of 3.9 per 100,000 using the years from 1978 to 1999, with a lower rate in earlier decades.

Between 1.3% and 10% of cases are of the adult form. The age at onset is variable (6–62 yr). Two main clinical subtypes have been described: progressive myoclonus epilepsy (type A) and dementia with motor disturbances, such as cerebellar, extrapyramidal signs and dyskinesia (type B). Unlike the other NCLs retinal degeneration is absent. Pathologically the ceroid-lipofuscin accumulates mainly in neurons and contains subunit C of the mitochondrial ATP synthase.

Two independent families have been shown to have mutations in the DNAJC5 gene – one with a transvertion and the other with a deletion mutation. The muations occur in a cysteine-string domain, which is required for membrane targeting/binding, palmitoylation and oligomerization of the encoded protein cysteine-string protein alpha (CSPα). The mutations dramatically decrease the affinity of CSPα for the membrane. A second report has also located this disease to this gene.

Jansky–Bielschowsky disease is an extremely rare autosomal recessive genetic disorder that is part of the neuronal ceroid lipofuscinosis (NCL) family of neurodegenerative disorders. It is caused by the accumulation of lipopigments in the body due to a deficiency in tripeptidyl peptidase I as a result of a mutation in the TPP1 gene. Symptoms appear between ages 2 and 4 and consist of typical neurodegenerative complications: loss of muscle function (ataxia), drug resistant seizures (epilepsy), apraxia, development of muscle twitches (myoclonus), and vision impairment. This late-infantile form of the disease progresses rapidly once symptoms are onset and ends in death between age 8 and teens. The prevalence of Jansky–Bielschowsky disease is unknown, however NCL collectively affects an estimated 1 in 100,000 individuals worldwide. Jansky–Bielschowsky disease is also known as: late-infantile Batten disease, LINCL, or neuronal ceroid lipofuscinosis.

Kufs disease is one of many diseases categorized under a disorder known as neuronal ceroid lipofuscinosis (NCLs). NCLs are broadly described to create problems with vision, movement and cognitive function. Among all NCLs diseases, Kufs is the only one that does not affect vision, and although this is a distinguishing factor of Kufs, NCLs are typically differentiated by the age at which they appear in a patient

The majority of cases are a result of mutations in the TPP1 gene, however mutations in the CLN5, CLN6, CLN8, MFSD8, and PPT1 genes also account for a small amount of cases. These mutations result in reduced activity of peptidase enzymes, particularly affecting lysosomes, but other mutations can affect protein catabolism in white blood cells, fibroblasts, and chorionic villi. The reduced function of these enzymes results in insufficient or incomplete breakdown of proteins, consequently resulting in the buildup of lipopigments in the lysosome. Though the accumulation of lipopigments occurs throughout the body, neurons are especially vulnerable to damage by lipopigment aggregation; a ubiquitous accumulation in lipopigments occurs in neurons, primarily concentrated in the cerebral and cerebellar cortices. This accumulation results in atrophy in these regions of the brain, and cause the pathogenesis of signs and symptoms of Jansky–Bielschowsky disease. Currently, it is unclear what mechanism in relation to enzyme activity is responsible for the buildup of lipoproteins.

Treatment is limited. Drugs can alleviate the symptoms, such as sleep difficulties and epilepsy. Physiotherapy helps affected children retain the ability to remain upright for as long as possible, and prevents some of the pain.

Recent attempts to treat INCL with cystagon have been unsuccessful.

HPS is one of the rare lung diseases currently being studied by The Rare Lung Diseases Consortium (RLDC). The RLDC is part of the Rare Diseases Clinical Research Network (RDCRN), an initiative of the Office of Rare Diseases Research (ORDR), of the National Center for Advancing Translational Sciences (NCATS). The RLDC is dedicated to developing new diagnostics and therapeutics for patients with rare lung diseases, through collaboration between the NIH, patient organizations and clinical investigators.

Infantile neuronal ceroid lipofuscinoses (INCL) or Santavuori disease or Hagberg-Santavuori disease or Santavuori-Haltia disease or Infantile Finnish type neuronal ceroid lipofuscinosis or Balkan disease is a form of NCL and inherited as a recessive autosomal genetic trait. The disorder is progressive, degenerative and fatal, extremely rare worldwide – with approximately 60 official cases reported by 1982, perhaps 100 sufferers in total today – but relatively common in Finland due to the local founder effect.

The course of HPS has been mild in rare instances of the disorder, however, the general prognosis is still considered to be poor.

The disease can cause dysfunctions of the lungs, intestine, kidneys, and heart. The major complication of most forms of the disorder is pulmonary fibrosis, which typically exhibits in patients ages 40–50 years. This is a fatal complication seen in many forms of HPS, and is the usual cause of death from the disorder. HPS patients who develop pulmonary fibrosis typically have type 1 or type 4.

Life expectancy is only moderately affected by NE because the rate of disease progression is slow. Patients usually survive past 40-50 years of age.

Type A and Type B Kufs disease are caused by mutations in two sets of different genes. Both gene sets are responsible for producing proteins and enzymes that are heavily involved in protein degradation and excretion in the cell – specifically, the nerve cell.

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.

It was first described in 1903.

Sandhoff disease, also known as Sandhoff–Jatzkewitz disease, variant 0 of GM2-Gangliosidosis or Hexosaminidase A and B deficiency, is a lysosomal genetic, lipid storage disorder caused by the inherited deficiency to create functional beta-hexosaminidases A and B. These catabolic enzymes are needed to degrade the neuronal membrane components, ganglioside GM2, its derivative GA2, the glycolipid globoside in visceral tissues, and some oligosaccharides. Accumulation of these metabolites leads to a progressive destruction of the central nervous system and eventually to death. The rare autosomal recessive neurodegenerative disorder is clinically almost indistinguishable from Tay–Sachs disease, another genetic disorder that disrupts beta-hexosaminidases A and S. There are three subsets of Sandhoff disease based on when first symptoms appear: classic infantile, juvenile and adult late onset.

The only country that Unverricht–Lundborg disease has a reported incidence is in Finland, where it is reported to occur in 4 in 100,000 individuals. However, ULD has only become well defined recently, and it is likely still under diagnosed, so the actual incidence may be different that what is currently known. Other countries with known cases include countries in the Mediterranean region including Italy, France, Tunisia, Algeria, and Morocco, as well as the United States.

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 10 genes lead to the development of Batten disease.

For early Unverricht–Lundborg disease patients, the disease would begin to progress early and lack of effective treatment meant a quick progression. In many cases the patient would require a wheelchair for mobility, and would die at a young age.

However, increased knowledge about the disease and improved treatment and medication has led to a dramatic improvement in prognosis for individuals with ULD. Antiepileptic drugs reduce the occurrence of seizures and myoclonus, which leads to a decrease in the damage caused in the brain due to seizures and the body due to falls resulting from the seizures. As a result, individuals with Unverricht–Lundborg disease are now much less likely to end up in a wheelchair, which eliminates the chance of complications involved with being a wheelchair user. All these factors have increased the outlook for patients. Due to the progressive nature of the disease, depression is prevalent, but support of family and friends as well as proper treatment can help. While early patients with ULD had a life expectancy of around 24 years, there have recently been reported cases of individuals living to near-normal ages.

Sandhoff disease can be detected through the following procedures (before it is apparent through physical examination): a biopsy removing a sample of tissue from the liver, genetic testing, molecular analysis of cells and tissues (to determine the presence of a genetic metabolic disorder), enzyme assay, and occasionally a urinalysis to determine if the above-noted compounds are abnormally stored within the body. For a child to suffer from this disease, both parents must be carriers, and both must transmit the mutation to the child. Thus, even in the case where both parents have the mutation, there is only a 25 percent chance their child will inherit the condition. Frequently, parents are given the opportunity to have a DNA screening if they are at high risk, to determine their carrier status before they have children. However, it is also highly recommended to undergo testing even for those parents who do not have a family history of Sandhoff disease. Over 95% of the families that have children with Sandhoff disease had no known prior family history of the condition, as the mutation in the HEXB gene is "silent," or recessive, and often passed undetected from one generation to the next Naturally, if an individual carries the mutation, he or she has a risk of transmitting it to the unborn child. Genetic counseling is recommended for those who have the mutation.

The most well known laboratory to perform the blood tests is through Lysosomal Diseases Testing Laboratory, Jefferson University with Dr. Wenger. Dr. Wenger’s laboratory does testing for all lysosomal diseases including Sandhoff and Tay-Sachs. They test for build-up of certain toxins in the body as well as a low count of enzymes.

It is possible for parents who are about to have a child or had a child with Sandhoff Disease can have a PGD or PEGD. PEGD is pre-embryonic genetic diagnosis for the parents that would not benefit from a pre-implantation genetic diagnosis because of their religion or negative attitude for the discarding of embryos. PEGD sequences the genome of the embryo to be produced by two parents if they were to conceive a child. If the family has a history of Sandhoff disease it is recommended they have their genome sequenced to ensure they are not carriers or to sequence the genome of their child.

Northern epilepsy syndrome or progressive epilepsy with mental retardation (EPMR) is a subtype of neuronal ceroid lipofuscinosis and a rare disease that is regarded as a Finnish heritage disease. Unlike most Finnish heritage diseases, this syndrome has been reported only in Finland.

The disease is characterized by seizures in early childhood that progressively get worse until after puberty. Once the onset of seizures occurs, mental degradation is seen. This continues into adulthood even after seizure frequency has decreased. The cause of the disease is a missense mutation in chromosome 8. The creation of a new protein occurs and the lipid content of the brain is altered because of it. The ratio of the mutation carriers is 1:135. There is nothing that has been found to stop the progression of the disease, but symptomatic approaches, such as the use of benzodiazepines, have helped control seizures.

There are multiple symptoms that can help this disease to be diagnosed, this disease is marked by the presence of acanthocytes in blood (these acanthocytes can sometimes be absent or even make a late appearance in the course of the disease.) and neurodegeneration causing a choreiform movement disorder.

Another one of them would be that this disease should be considered in patients who have elevated levels of acanthocytes in a peripheral blood film.

The serum creatine kinase is often elevated in the body of the people who are affected by this disease.

People afflicted by this disease also experience a loss of neurons. Loss of neurons is a hallmark of neurodegenerative diseases. Due to the generally non-regenerative nature of neuronal cells in the adult central nervous system, this results in an irreversible and fatal process of neurodegeneration. There is also the presence of several movement related disorders including chorea, dystonia and bradykinesia, one of the more incapacitating ones includes Truncal spasms.

All brain iron disorders were previously labeled Hallervorden-Spatz syndrome, after the scientists who first discovered individuals with abnormal iron levels in 1922. Brain iron disorders are now divided into three categories: genetic neurodegeneration with brain iron accumulation, genetic systemic iron accumulation with neurologic features, and acquired diseases associated with iron excess or iron deficiency. Neuroferritinopathy is classified under the first category, genetic neurodegeneration with brain iron accumulation. Neuroferritinopathy is classified as a late-onset basal ganglia disease and is a dominantly inherited neurodegenerative disease. Four different alleles are responsible for neuroferritinopathy. Three arise from nucleotide insertions in the ferritin light chain (FTL) polypeptide gene while the fourth arises from a missense mutation in the FTL gene.

Neuroferritinopathy or adult-onset basal ganglia disease is a genetic neurodegenerative disorder characterized by the accumulation of iron in the basal ganglia, cerebellum, and motor cortex of the human brain. Symptoms, which are extrapyramidal in nature, progress slowly and generally do not become apparent until adulthood. These symptoms include chorea, dystonia, and cognitive deficits which worsen with age.

This disorder is autosomal dominant and is caused by mutations in the gene encoding the light chain subunit of the ferritin protein. Wild type ferritin functions as a buffer for iron, sequestering it and controlling its release. Thus, mutations in the light chain of ferritin result in the accumulation of iron in the brain which can be imaged using MRI. Currently, neuroferritinopathy is the only neurodegenerative disease with an iron accumulation in the brain classified as an autosomal dominant syndrome.

Treatment of neuroferritinopathy is focused on managing symptoms associated with chorea and dystonia using standard medications for each. The disorder is progressive and symptoms become worse with age. Fewer than 100 cases of neuroferritinopathy have been reported since its identification in 2001. Its incidence has been largely localized to Northeast England suggesting a founder effect. Due to its genetic nature, current research is focused on therapeutic management of the symptoms caused by the disorder.

Chorea-acanthocytosis (ChAc, also called Choreoacanthocytosis), is a rare hereditary disease caused by a mutation of the gene that directs structural proteins in red blood cells. It belongs to a group of four diseases characterized under the name Neuroacanthocytosis. When a patient's blood is viewed under a microscope, some of the red blood cells appear thorny. These thorny cells are called acanthocytes.

Other effects of the disease may include epilepsy, behaviour changes, muscle degeneration, and neuronal degradation similar to Huntington's Disease. The average age of onset of symptoms is 35 years. The disease is incurable and inevitably leads to premature death.

Some more information about Chorea-acanthocytosis is that it is a very complex autosomal recessive adult-onset neurodegenerative disorder. It often shows itself as a mixed movement disorder, in which chorea, tics, dystonia and even parkinsonism may appear as a symptom.

This disease is also characterized by the presence of a few different movement disorders including chorea, dystonia etc.

Chorea-acanthocytosis is considered an autosomal recessive disorder, although a few cases with autosomal dominant inheritance have been noted.

The symptoms of LSD vary, depending on the particular disorder and other variables such as the age of onset, and can be mild to severe. They can include developmental delay, movement disorders, seizures, dementia, deafness, and/or blindness. Some people with LSDhave enlarged livers (hepatomegaly) and enlarged spleens (splenomegaly), pulmonary and cardiac problems, and bones that grow abnormally.

Currently, no cure for Zellweger syndrome is known, nor is a course of treatment made standard. Infections should be guarded against to prevent such complications as pneumonia and respiratory distress. Other treatment is symptomatic and supportive. Patients usually do not survive beyond one year of age.

PME accounts for less than 1% of epilepsy cases at specialist centres. The incidence and prevalence of PME is unknown, but there are considerable geography and ethnic variations amongst the specific genetic disorders. One cause, Unverricht Lundborg Disease, has an incidence of at least 1:20,000 in Finland.