Fatal insomnia | |
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Cranial imaging of an FFI patient. In the MRI, there are abnormal signals in the bilateral frontoparietal subcortical area. MRA showed smaller distal branches of cerebral arteries. | |
Specialty | Neurology, Psychiatry, Sleep medicine, Neuropathology |
Symptoms | Progressive insomnia, ataxia, double vision, weight loss, high blood pressure, excessive sweating |
Complications | Permanent state of hypnagogia later in the illness |
Usual onset | 45–50 years old [1] |
Types | Fatal familial insomnia, sporadic fatal insomnia [2] |
Causes | Genetic mutation, sporadic form (very rare) |
Risk factors | Family history |
Diagnostic method | Suspected based on symptoms, supported by sleep study, PET scan and genetic testing (if familial form is suspected) [3] |
Differential diagnosis | Alzheimer's disease, frontotemporal dementia, other transmissible spongiform encephalopathies [4] |
Prevention | None |
Treatment | Supportive care [2] |
Medication | None |
Prognosis | Always fatal |
Frequency | 70 families worldwide are known to carry the gene associated with the disease, 37 sporadic cases diagnosed (as of September 20th, 2022) |
Deaths | <1 per year |
Fatal insomnia is an extremely rare neurodegenerative prion disease that results in trouble sleeping as its hallmark symptom. [2] The majority of cases are familial (fatal familial insomnia [FFI]), stemming from a mutation in the PRNP gene, with the remainder of cases occurring sporadically (sporadic fatal insomnia [sFI]). The problems with sleeping typically start out gradually and worsen over time. [4] Eventually, the patient will succumb to total insomnia (agrypnia excitata), most often leading to other symptoms such as speech problems, coordination problems, and dementia. [5] It results in death within a few months to a few years, and there is no known disease-modifying treatment. [2]
The disease has four stages: [6]
Clinically, FFI manifests with a disordered sleep-wake cycle, dysautonomia, motor disturbances, and neuropsychiatric disorders.
Other symptoms include profuse sweating, miosis (pinpoint pupils), sudden entrance into menopause or impotence, neck stiffness, and elevation of blood pressure and heart rate. The sporadic form of the disease often presents with double vision. Prolonged constipation is common as well. As the disease progresses, the person becomes stuck in a state of pre-sleep limbo, or hypnagogia, which is the state just before sleep in healthy individuals. During these stages, people commonly and repeatedly move their limbs as if they were dreaming. [7]
The age of onset is variable, ranging from 13 to 60 years, with an average of 50. [8] The disease can be detected prior to onset by genetic testing. [9] Death usually occurs between 6–36 months from onset. The presentation of the disease varies considerably from person to person, even among people within the same family; in the sporadic form, for example, sleep problems are not commonly reported and early symptoms are ataxia, cognitive impairment, and double vision. [10]
This section may be too technical for most readers to understand.(September 2023) |
Fatal familial insomnia is a rare hereditary prion disease that is associated with a mutation in PRNP. The gene, which provides instructions for making the prion protein PrPC, is located on the short arm of chromosome 20 at position p13. [11] Individuals with FFI or familial Creutzfeldt–Jakob disease (fCJD) both carry a mutation at codon 178 of the prion protein gene. FFI is also invariably linked to the presence of the methionine codon at position 129 of the mutant allele, whereas fCJD is linked to the presence of the valine codon at that position. The disease occurs when there is a change of amino acid at position 178 in which asparagine is found instead of the normal aspartic acid. This has to be accompanied with a methionine at position 129. [12]
FFI is an autosomal dominant disease caused by a missense GAC-to-AAC mutation at codon 178 of the PRNP prion protein gene located on chromosome 20, along with the presence of the methionine polymorphism at position 129 of the mutant allele. Pathologically, FFI is characterized predominantly by thalamic degeneration—especially in the medio-dorsal and anteroventral nuclei. [13] Phenotypic variability is a perplexing feature of FFI. [14]
Given its striking clinical and neuropathologic similarities with fatal familial insomnia (FFI), a genetic prion disease linked to a point mutation at codon 178 (D178N) in the PRNP coupled with methionine at codon 129, the MM2T subtype is also known as sporadic FI (sFI). Transmission studies using susceptible transgenic mice have consistently demonstrated that the same prion strain is associated with both sFI and FFI. In contrast to what has been the rule for the most common neurodegenerative disorders, sFI is rarer than its genetic counterpart. Whereas the recognized patients with FFI are numerous and belong to >50 families worldwide, only about 30 cases of CJD MM2T and a few cases with mixed MM2T and MM2C features (MM2T+C) have been recorded to date.
In itself the presence of prions causes reduced glucose to be used by the thalamus and a mild hypo-metabolism of the cingulate cortex. The extent of this symptom varies between two variations of the disease, these being those presenting methionine homozygotes at codon 129 and methionine/valine heterozygotes being the most severe in the latter. [15] Given the relationship between the involvement of the thalamus in regulating sleep and alertness, a causal relationship can be drawn and is often mentioned as the cause. [16] [17]
This section may be too technical for most readers to understand.(June 2024) |
Diagnosis is based on symptoms and can be supported by a sleep study, a PET scan and genetic testing if the patient's family has a history of the disease. As with other prion diseases, the diagnosis can be confirmed only by a brain autopsy post-mortem.
The real-time quaking-induced conversion (RT-QuIC), a highly sensitive assay that detects minute amounts of PrPSc in the cerebrospinal fluid (CSF), has been reported to have a sensitivity of 50% in FFI and sFI.[Cracco et al. Handb Clin Neurol 2018][Mock et al. Sci Rep. 2021] However, this low sensitivity may change since the examination was based on a low number of cases, and the RT-QuIC technology is continuously evolving.
A test that measures the cerebral metabolic rate of glucose by positron emission tomography (PET), referred to as [18F]-FDG-PET, has demonstrated severe hypometabolism of the thalamus bilaterally in FFI and sFI, also in the earliest stages of the disease. This hypometabolism then spreads, eventually impacting most cortical regions.[Cortelli et al. Brain 2006] The complexity and cost of this test currently impede its use in routine diagnosis.
Other diseases involving the mammalian prion protein are known. [18] Some are transmissible (TSEs, including FFI) such as kuru, bovine spongiform encephalopathy (BSE, also known as mad cow disease) in cattle and chronic wasting disease in American deer and American elk in some areas of the United States and Canada, as well as Creutzfeldt–Jakob disease (CJD). Until recently prion diseases were thought to be transmissible only by direct contact with infected tissue, such as from eating infected tissue, transfusion or transplantation; research suggests that prions can be transmitted by aerosols but that the general public is not at risk of airborne infection. [19]
Treatment involves palliative care. [2] There is conflicting evidence over the use of sleeping pills, including barbiturates, as a treatment for the disease. [20] [21] Symptoms of fatal familial insomnia may be treated with medications.[ contradictory ]
Clonazepam may be prescribed to treat muscle spasms, and eszopiclone or zolpidem may be prescribed to help treat insomnia. However these drugs do not work in the long term. [22] [ better source needed ]
Like all prion diseases, the disease is invariably fatal. [23] [2] Life expectancy ranges from seven months to six years, [2] with an average of 18 months. [23]
Fatal insomnia was first described by Elio Lugaresi et al. in 1986.
In 1998 40 families were known to carry the gene for FFI globally: eight German, five Italian, four American, two French, two Australian, two British, one Japanese and one Austrian. [24] In the Basque Country of Spain, 16 family cases of the 178N mutation were seen between 1993 and 2005 related to two families with a common ancestor in the 18th century. [25] In 2011, another family was added to the list when researchers found the first man in the Netherlands to be diagnosed with FFI. Whilst he had lived in the Netherlands for 19 years, he was of Egyptian descent. [26] Other prion diseases are similar to FFI and may be related but are missing the D178N gene mutation. [7]
As of 20 September 2022 [update] , 37 cases of sporadic fatal insomnia have been diagnosed. [3] Unlike in FFI, those with sFI do not have the D178N mutation in the PRNP-prion gene; they all have a different mutation in the same gene causing methionine homozygosity at codon 129. [27] [28] Nonetheless, the methionine presence in lieu of the valine (Val129) is what causes the sporadic form of disease. The targeting of this mutation has been suggested as a strategy for treatment, or possibly as a cure for the disease. [29]
In late 1983 Italian neurologist/sleep expert Dr Ignazio Roiter received a patient at the University of Bologna hospital's sleep institute. The man, known only as Silvano, decided in a rare moment of consciousness to be recorded for future studies and to donate his brain for research in hopes of finding a cure for future victims. [30]
In 1986, Lugaresi and colleagues first named and described in detail the clinical and histopathological features of fatal familial insomnia (FFI) [Lugaresi et al. NEJM]. This report was mostly based on a patient referred to as Silvano, who was diagnosed with sleep impairment in 1983 by Dr. Ignazio Roiter. Dr. Roiter referred the case to Prof. Elio Lugaresi, a well-known sleep expert, who, along with his colleagues, carried out advanced sleep analyses. As Silvano's condition quickly deteriorated, Lugaresi arranged for a postmortem neuropathological examination of the brain to be carried out by Dr. Gambetti, Lugaresi's former trainee. The collaboration of these two groups led to the 1986 publication [27]. At the time, a prion disease was not suspected due to a lack of prion-related histpathology and frozen brain tissue for advanced analysis. However, due to the devotion of Dr. Roiter and Silvano's family, more cases were obtained, resulting in the classification of FFI as a familial prion disease tied to the 178Asn genetic mutation. [Medori et al. NEJM, 1992]
In an article published in 2006, Schenkein and Montagna wrote of a 52-year-old American man who was able to exceed the average survival time by nearly one year with various strategies that included vitamin therapy and meditation, different stimulants and hypnotics and even complete sensory deprivation in an attempt to induce sleep at night and increase alertness during the day. He managed to write a book and drive hundreds of miles in this time, but nonetheless, over the course of his trials, the man succumbed to the classic four-stage progression of the illness. [30]
In 2011, the first reported case in the Netherlands was of a 57-year-old man of Egyptian descent. The man came in with symptoms of double vision and progressive memory loss, and his family also noted he had recently become disoriented, paranoid and confused. Whilst he tended to fall asleep at random during daily activities, he experienced vivid dreams and random muscular jerks during normal slow-wave sleep. After four months of these symptoms, he began to have convulsions in his hands, trunk and lower limbs while awake. The person died at age 58, seven months after the onset of symptoms. An autopsy revealed mild atrophy of the frontal cortex and moderate atrophy of the thalamus. The latter is one of the most common signs of FFI. [26]
Still with unclear benefit in humans, a number of treatments have had tentative success in slowing disease progression in animal models, including pentosan polysulfate, mepacrine, and amphotericin B. [3] As of 2016 [update] , a study investigating doxycycline is being carried out. [3] [31]
In 2009, a mouse model was made for FFI. These mice expressed a humanized version of the PrP protein that also contains the D178N FFI mutation. [32] These mice appear to have progressively fewer and shorter periods of uninterrupted sleep, damage in the thalamus, and early deaths, similar to humans with FFI.[ citation needed ]
The Prion Alliance was established by husband and wife duo Eric Minikel and Sonia Vallabh after Vallabh's mother was diagnosed with the fatal disease. [33] They conduct research at the Broad Institute to develop therapeutics for human prion diseases. Other research interests involve identifying biomarkers to track the progression of prion disease in living people. [34] [35]
Creutzfeldt–Jakob disease (CJD), also known as subacute spongiform encephalopathy or neurocognitive disorder due to prion disease, is a fatal neurodegenerative disease. Early symptoms include memory problems, behavioral changes, poor coordination, and visual disturbances. Later symptoms include dementia, involuntary movements, blindness, weakness, and coma. About 70% of people die within a year of diagnosis. The name "Creutzfeldt–Jakob disease" was introduced by Walther Spielmeyer in 1922, after the German neurologists Hans Gerhard Creutzfeldt and Alfons Maria Jakob.
A prion is a misfolded protein that induces misfolding in normal variants of the same protein, leading to cellular death. Prions are responsible for prion diseases, known as transmissible spongiform encephalopathy (TSEs), which are fatal and transmissible neurodegenerative diseases affecting both humans and animals. These proteins can misfold sporadically, due to genetic mutations, or by exposure to an already misfolded protein, leading to an abnormal three-dimensional structure that can propagate misfolding in other proteins.
Morvan's syndrome is a rare, life-threatening autoimmune disease named after the nineteenth century French physician Augustin Marie Morvan. "La chorée fibrillaire" was first coined by Morvan in 1890 when describing patients with multiple, irregular contractions of the long muscles, cramping, weakness, pruritus, hyperhidrosis, insomnia and delirium. It normally presents with a slow insidious onset over months to years. Approximately 90% of cases spontaneously go into remission, while the other 10% of cases lead to death.
Transmissible spongiform encephalopathies (TSEs), also known as prion diseases, are a group of progressive, incurable, and fatal conditions that are associated with prions and affect the brain and nervous system of many animals, including humans, cattle, and sheep. According to the most widespread hypothesis, they are transmitted by prions, though some other data suggest an involvement of a Spiroplasma infection. Mental and physical abilities deteriorate and many tiny holes appear in the cortex causing it to appear like a sponge when brain tissue obtained at autopsy is examined under a microscope. The disorders cause impairment of brain function which may result in memory loss, personality changes, and abnormal or impaired movement which worsen over time.
Primary familial brain calcification (PFBC), also known as familial idiopathic basal ganglia calcification (FIBGC) and Fahr's disease, is a rare, genetically dominant or recessive, inherited neurological disorder characterized by abnormal deposits of calcium in areas of the brain that control movement. Through the use of CT scans, calcifications are seen primarily in the basal ganglia and in other areas such as the cerebral cortex.
Hypermetabolism is defined as an elevated resting energy expenditure (REE) > 110% of predicted REE. Hypermetabolism is accompanied by a variety of internal and external symptoms, most notably extreme weight loss, and can also be a symptom in itself. This state of increased metabolic activity can signal underlying issues, especially hyperthyroidism. Patients with Fatal familial insomnia can also present with hypermetabolism; however, this universally fatal disorder is exceedingly rare, with only a few known cases worldwide. The drastic impact of the hypermetabolic state on patient nutritional requirements is often understated or overlooked as well.
Gerstmann–Sträussler–Scheinker syndrome (GSS) is an extremely rare, always fatal neurodegenerative disease that affects patients from 20 to 60 years in age. It is exclusively heritable, and is found in only a few families all over the world. It is, however, classified with the transmissible spongiform encephalopathies (TSE) due to the causative role played by PRNP, the human prion protein. GSS was first reported by the Austrian physicians Josef Gerstmann, Ernst Sträussler and Ilya Scheinker in 1936.
Pantothenate kinase-associated neurodegeneration (PKAN), formerly called Hallervorden–Spatz syndrome, is a genetic degenerative disease of the brain that can lead to parkinsonism, dystonia, dementia, and ultimately death. Neurodegeneration in PKAN is accompanied by an excess of iron that progressively builds up in the brain.
The major prion protein (PrP) is encoded in the human body by the PRNP gene also known as CD230. Expression of the protein is most predominant in the nervous system but occurs in many other tissues throughout the body.
Familial hemiplegic migraine (FHM) is an autosomal dominant type of hemiplegic migraine that typically includes weakness of half the body which can last for hours, days, or weeks. It can be accompanied by other symptoms, such as ataxia, coma, and paralysis. Migraine attacks may be provoked by minor head trauma. Some cases of minor head trauma in patients with hemiplegic migraine can develop into delayed cerebral edema, a life-threatening medical emergency. Clinical overlap occurs in some FHM patients with episodic ataxia type 2 and spinocerebellar ataxia type 6, benign familial infantile epilepsy, and alternating hemiplegia of childhood.
Fundic gland polyposis is a medical syndrome where the fundus and the body of the stomach develop many fundic gland polyps. The condition has been described both in patients with familial adenomatous polyposis (FAP) and attenuated variants (AFAP), and in patients in whom it occurs sporadically.
Variant Creutzfeldt–Jakob disease (vCJD), formerly known as New variant Creutzfeldt–Jakob disease (nvCJD) and referred to colloquially as "mad cow disease" or "human mad cow disease" to distinguish it from its BSE counterpart, is a fatal type of brain disease within the transmissible spongiform encephalopathy family. Initial symptoms include psychiatric problems, behavioral changes, and painful sensations. In the later stages of the illness, patients may exhibit poor coordination, dementia and involuntary movements. The length of time between exposure and the development of symptoms is unclear, but is believed to be years to decades. Average life expectancy following the onset of symptoms is 13 months.
Paroxysmal kinesigenic dyskinesia (PKD), also called paroxysmal kinesigenic choreoathetosis (PKC), is a rare hyperkinetic movement disorder of the paroxysmal dyskinesias characterized by attacks of involuntary movements, which are triggered by sudden voluntary movements. The number of attacks can increase during puberty and decrease in a person's 20s to 30s. Involuntary movements can take many forms such as ballism, chorea or dystonia and usually only affect one side of the body or one limb in particular.
Early-onset Alzheimer's disease (EOAD), also called younger-onset Alzheimer's disease (YOAD), is Alzheimer's disease diagnosed before the age of 65. It is an uncommon form of Alzheimer's, accounting for only 5–10% of all Alzheimer's cases. About 60% have a positive family history of Alzheimer's and 13% of them are inherited in an autosomal dominant manner. Most cases of early-onset Alzheimer's share the same traits as the "late-onset" form and are not caused by known genetic mutations. Little is understood about how it starts.
Amyotrophic lateral sclerosis (ALS), also known as motor neurone disease (MND) or Lou Gehrig's disease in the United States, is a rare, terminal neurodegenerative disorder that results in the progressive loss of both upper and lower motor neurons that normally control voluntary muscle contraction. ALS is the most common form of the motor neuron diseases. ALS often presents in its early stages with gradual muscle stiffness, twitches, weakness, and wasting. Motor neuron loss typically continues until the abilities to eat, speak, move, and, lastly, breathe are all lost. While only 15% of people with ALS also fully develop frontotemporal dementia, an estimated 50% face at least some minor difficulties with thinking and behavior. Depending on which of the aforementioned symptoms develops first, ALS is classified as limb-onset or bulbar-onset.
Variably protease-sensitive prionopathy (VPSPr) is a sporadic prion protein disease first described in an abstract for a conference on prions in 2006, and this study was published in a 2008 report on 11 cases. The study was conducted by Gambetti P., Zou W.Q., and coworkers from the United States National Prion Disease Pathology Surveillance Center. It was first identified as a distinct disease in 2010 by Zou W.Q. and coworkers from the United States National Prion Disease Pathology Surveillance Center.
Louis Ptáček is an American neurologist and professor who contributed greatly to the field of genetics and neuroscience. He was also an HHMI investigator from 1997 to 2018. His chief areas of research include the understanding of inherited Mendelian disorders and circadian rhythm genes. Currently, Ptáček is a neurology professor and a director of the Division of Neurogenetics in University of California, San Francisco, School of Medicine. His current investigations primarily focus on extensive clinical studies in families with hereditary disorders, which include identifying and characterizing the genes responsible for neurological variations.
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Familial sleep traits are heritable variations in sleep patterns, resulting in abnormal sleep-wake times and/or abnormal sleep length.
PrP systemic amyloidosis is an extremely rare and unusual form of inherited prion disease. Unlike most prion diseases, PrP systemic amyloidosis is not isolated to the central nervous system. The prion amyloid has extensive peripheral involvement, finding its way to peripheral nerves and internal organs. The initial presentation of this disease involves chronic diarrhea and autonomic neuropathy before progressing into neurodegeneration.