Hereditary spastic paraplegia (HSP) is a group of inherited diseases whose main feature is a progressive gait disorder. The disease presents with progressive stiffness (spasticity) and contraction in the lower limbs. HSP is also known as hereditary spastic paraparesis, familial spastic paraplegia, French settlement disease, Strumpell disease, or Strumpell-Lorrain disease. The symptoms are a result of dysfunction of long axons in the spinal cord. The affected cells are the primary motor neurons; therefore, the disease is an upper motor neuron disease. HSP is not a form of cerebral palsy even though it physically may appear and behave much the same as spastic diplegia. The origin of HSP is different from cerebral palsy. Despite this, some of the same anti-spasticity medications used in spastic cerebral palsy are sometimes used to treat HSP symptoms.
Spinocerebellar ataxia (SCA) is a progressive, degenerative, genetic disease with multiple types, each of which could be considered a neurological condition in its own right. An estimated 150,000 people in the United States have a diagnosis of spinocerebellar ataxia at any given time. SCA is hereditary, progressive, degenerative, and often fatal. There is no known effective treatment or cure. SCA can affect anyone of any age. The disease is caused by either a recessive or dominant gene. In many cases people are not aware that they carry a relevant gene until they have children who begin to show signs of having the disorder.
Machado–Joseph disease (MJD), also known as Machado–Joseph Azorean disease, Machado's disease, Joseph's disease or spinocerebellar ataxia type 3 (SCA3), is a rare autosomal dominantly inherited neurodegenerative disease that causes progressive cerebellar ataxia, which results in a lack of muscle control and coordination of the upper and lower extremities. The symptoms are caused by a genetic mutation that results in an expansion of abnormal "CAG" trinucleotide repeats in the ATXN3 gene that results in an abnormal form of the protein ataxin which causes degeneration of cells in the hindbrain. Some symptoms, such as clumsiness and rigidity, make MJD commonly mistaken for drunkenness or Parkinson's disease.
Spinocerebellar ataxia type 6 (SCA6) is a rare, late-onset, autosomal dominant disorder, which, like other types of SCA, is characterized by dysarthria, oculomotor disorders, peripheral neuropathy, and ataxia of the gait, stance, and limbs due to cerebellar dysfunction. Unlike other types, SCA 6 is not fatal. This cerebellar function is permanent and progressive, differentiating it from episodic ataxia type 2 (EA2) where said dysfunction is episodic. In some SCA6 families, some members show these classic signs of SCA6 while others show signs more similar to EA2, suggesting that there is some phenotypic overlap between the two disorders. SCA6 is caused by mutations in CACNA1A, a gene encoding a calcium channel α subunit. These mutations tend to be trinucleotide repeats of CAG, leading to the production of mutant proteins containing stretches of 20 or more consecutive glutamine residues; these proteins have an increased tendency to form intracellular agglomerations. Unlike many other polyglutamine expansion disorders expansion length is not a determining factor for the age that symptoms present.
Spinocerebellar ataxia type 13 (SCA13) is a rare autosomal dominant disorder, which, like other types of SCA, is characterized by dysarthria, nystagmus, and ataxia of gait, stance and the limbs due to cerebellar dysfunction. Patients with SCA13 also tend to present with epilepsy, an inability to run, and increased reflexes. This cerebellar dysfunction is permanent and progressive. SCA13 is caused by mutations in KCNC3, a gene encoding a voltage-gated potassium channel KV3.3. There are two known mutations in this gene causative for SCA13. Unlike many other types of SCA, these are not polyglutamine expansions but, rather, point mutations resulting in channels with no current or altered kinetics.
Carnitine O-palmitoyltransferase 2, mitochondrial is an enzyme that in humans is encoded by the CPT2 gene.
The human gene SPAST codes for the microtubule-severing protein of the same name, commonly known as spastin.
Atlastin-1, is a protein that in humans is encoded by the ATL1 gene.
Paraplegin is a protein that in humans is encoded by the SPG7 gene located on chromosome 16.
Sacsin also known as DnaJ homolog subfamily C member 29 (DNAJC29) is a protein that in humans is encoded by the SACS gene. Sacsin is a Hsp70 co-chaperone.
Kinesin family member 5A is a protein that in humans is encoded by the KIF5A gene. It is part of the kinesin family of motor proteins.
Puratrophin-1 is a protein that in humans is encoded by the PLEKHG4 gene.
Tau tubulin kinase 2 is a protein in humans that is encoded by the TTBK2 gene. This gene encodes a serine-threonine kinase that putatively phosphorylates tau and tubulin proteins. Mutations in this gene cause spinocerebellar ataxia type 11 (SCA11); a neurodegenerative disease characterized by progressive ataxia and atrophy of the cerebellum and brainstem.
Potassium voltage-gated channel, Shaw-related subfamily, member 3 also known as KCNC3 or Kv3.3 is a protein that in humans is encoded by the KCNC3.
Gillespie syndrome, also called aniridia, cerebellar ataxia and mental deficiency, is a rare genetic disorder. The disorder is characterized by partial aniridia, ataxia, and, in most cases, intellectual disability. It is heterogeneous, inherited in either an autosomal dominant or autosomal recessive manner. Gillespie syndrome was first described by American ophthalmologist Fredrick Gillespie in 1965.
Gap junction gamma-2 (GJC2), also known as connexin-46.6 (Cx46.6) and connexin-47 (Cx47) and gap junction alpha-12 (GJA12), is a protein that in humans is encoded by the GJC2 gene.
Fatty acid 2-hydroxylase is a protein that in humans is encoded by the FA2H gene.
Acetyl-coenzyme A transporter 1 also known as solute carrier family 33 member 1 (SLC33A1) is a protein that in humans is encoded by the SLC33A1 gene.
Autosomal dominant cerebellar ataxia, deafness, and narcolepsy (ADCADN) is a rare progressive genetic disorder that primarily affects the nervous system and is characterized by sensorineural hearing loss, narcolepsy with cataplexy, and dementia later in life. People with this disorder usually start showing symptoms when they are in their early-mid adulthoods. It is a type of autosomal dominant cerebellar ataxia.
Spastic paraplegia 6 is a rare type of hereditary spastic paraplegia characterized by muscle tone and bladder anomalies associated with pes cavus and specific hyperreflexia.
