如果你曾经熬过一两个通宵，你可能会盯着天花板，想知道自己是否真的会因精疲力竭而死。 从技术上讲，答案是肯定的，但对于绝大多数人来说，身体会反弹。 慢性睡眠不足会带来一系列令人不快的症状——烦躁、脑雾、疲劳——但这些症状是可逆的。
有一个例外。 一种极其罕见的疾病，称为“致命的家族性失眠症”，无法康复。 这是一种神经退行性疾病，会慢慢关闭身体的睡眠能力，直到系统崩溃。 这不仅仅是失眠。 这是一种绝症。
虽然确切的起源已被历史遗忘，但研究人员将这种疾病的血统追溯到 1700 年代末和 1800 年代初的两名意大利男性。 1765 年，一名威尼斯男子死于与该疾病相符的症状。1836 年，另一名威尼斯男子死于几乎可以肯定致命的家族性失眠症。两人都将缺陷基因遗传给了后代。 这种疾病至今仍然存在，尽管极为罕见。 据记录，仅发生约 100 例死亡。 直到 1986 年，它才被正式承认为一种独特的疾病。
这种病是如何遗传的？
This condition is an autosomal dominant neurodegenerative disease. This means that one copy of the defective gene is enough to cause the disease. Humans have 22 pairs of autosomes (non-sex chromosomes) and one pair of sex chromosomes. Mutations occur in either of these autosomal pairs.
具体来说，它是一种朊病毒病。 Prions are misfolded proteins, and 它们能诱导大脑中的正常蛋白质也发生错误折叠。 This process creates a chain reaction of damage. Prion diseases are divided into three categories.
- Acquired: Obtained from external sources such as 库鲁病（与食人习俗有关）。
- Spontaneous: Occurs spontaneously with no known cause or family history.
- 遗传性： Inherited through family.
致命的家族性失眠症主要是遗传性的。 Families with a history of this disease have a specific mutation in the prion protein gene called PRNP. This is often associated with a methionine polymorphism, another genetic marker commonly found in other neurodegenerative diseases. If you inherit this mutation, you have a 50% chance of passing it on to your children.
It is estimated that 28-40 families worldwide suffer from this problem. In rare cases, the disease can appear spontaneously (散发性致命失眠), but 家族遗传是常态。
有哪些症状和阶段？
朊病毒病具有共同特征：疲劳、认知能力下降、幻觉、肌肉僵硬以及行走或说话困难。 但致命的家族性失眠有着独特的轨迹。 标志性症状是失眠，但它会经历四个不同的阶段。
发病年龄通常为 48 岁左右，但也有报道年龄为 19 至 72 岁的病例。这种疾病传播得很快。 有些患者在症状出现后还能活两到三年。 其他人则在一年内死亡。
第一阶段
第一个迹象是持续失眠。 大约四个月后情况会恶化。 有些患者在睡眠不足变得严重之前就注意到了精神问题。 惊恐发作、偏执和恐惧症就会出现。 有趣的是，患者经常出现失眠恐惧症——害怕无法入睡。 当他们成功入睡时，梦境变得生动而令人不安。
第二阶段
这一阶段持续约五个月，精神症状加剧。 幻觉变得普遍。 当交感神经系统过度运转时，就会出现烦躁。 这种交感神经过度活跃会引发一系列身体反应：
* 皮质醇水平升高
* 心动过速（心率过快）
* 高血压
* 体温过高（体温过高）
* 多汗症（出汗过多）
* 呼吸急促（呼吸急促）
运动和认知功能开始衰退。 出现短期记忆丧失。 性格变化，包括抑郁和焦虑，变得明显。 运动和步态开始恶化。
第三阶段
这个阶段很短暂，仅持续约90天。 唤醒-睡眠周期完全被打乱。 完全失眠开始了。 没有休息。
第四阶段
最后阶段涉及认知能力快速下降和痴呆。 它可以持续长达六个月。 最终，患者失去自主移动或说话的能力，这种情况称为运动不能性沉默症。 随后是昏迷和死亡。
诊断与治疗
There is no cure for 致命的家族性失眠症。 Early diagnosis is difficult because the symptoms overlap with 其他疾病。 Doctors rely on family history, clinical evaluation, and genetic testing for the PRNP mutation. Sleep studies can show disturbances in the typical sleep architecture, but by then the damage has already started.
The treatment is palliative. The goal is to control the symptoms for as long as possible. Sleep aids have little effect because the thalamus, the brain’s sleep-regulating center, 正在退化。 Antipsychotics and benzodiazepines can be used to calm the restlessness, but they cannot 逆转潜在的朊病毒病理。
This disease is one of the most feared by the 医学界 because of its inevitability. It starts with a simple complaint “I can’t sleep” and ends with a complete shutdown of the body. For others, 睡眠不足 is a disadvantage. For people with this genetic mutation, it’s the first step toward a fatal conclusion.
The mystery of why the thalamus is specialized in sleep regulation is still unsolved. Research into prion diseases continues in the hope of finding ways to 阻止蛋白质错误折叠。 Until then, fatal familial insomnia 仍然是一种无声的、遗传性的 in the DNA of dozens of families around the world.
The Thalamus Under Siege
Insomnia is only the visible tip of the iceberg. Behind these sleepless nights lies a brutal reorganization of the body’s internal structure. Fatal familial insomnia (FFI) can cause more than just the inability to sleep. It systematically destroys the central nervous system, targeting the brain and spinal cord with devastating precision.
The greatest damage occurs to the thalamus. This deep brain structure acts as a central mediator for motor function and sensory information. In FFI, certain clusters of neurons (anterior-ventral and medio-dorsal thalamic neurons) begin to die. When these cells die, they cannot be regenerated. The brain simply cannot grow something new to replace it.
Instead, glial cells intervene. These support cells are responsible for maintaining communication between neurons and removing cellular waste. In response to widespread neuronal death, scar tissue forms, a process called gliosis. Scar tissue is inert. It cannot process sensory information or modulate motor signals. As a result, the entire system gradually weakens, and insomnia is the earliest and most obvious symptom of this internal collapse.
How is the diagnosis made (and why is it difficult)?
Recognizing FFI is difficult until the symptoms are fully apparent. A blood test cannot determine “yes” or “no”. Doctors rely on the patient’s reported symptoms, detailed family history, and genetic testing. Blood tests can help rule out other causes, and spinal fluid can be analyzed for certain markers.
Magnetic resonance imaging (MRI) and positron emission tomography (PET) can reveal structural and metabolic changes in the brain. Neurological and eye exams give additional clues about the functioning of the nervous system.
Perhaps the most telling signs come from electroencephalography (EEG), which maps the brain’s electrical activity. Healthy sleep follows a predictable cycle. In other words, four stages of NREM sleep followed by rapid eye movement (REM) sleep. In FFI patients, this pattern disappears almost immediately. Within a few months of starting, the brain waves slow down considerably. The brain skips important stages in the sleep cycle. Deep REM sleep disappears and is replaced by fragmented and ineffective rest. Daytime sleep duration shrinks relentlessly.
Early detection is based on genetic identification rather than electrographic patterns, as EEG patterns are only accurate if the patient already has symptoms.
No single diagnostic tool is sufficient. For example, electroencephalography (EEG) is not useful in the pre-symptomatic phase. MRI scans may appear normal in the early stages. A diagnosis is a puzzle, and all the pieces must fit together.
No Cure, Only Care
As of 2014, there is no cure for FFI. No treatment can stop the progression. The standard treatment is palliative care. The goal shifts from disease treatment to managing the suffering. Doctors focus on quality of life, trying to reduce neurodegeneration and disabling symptoms.
The research work is ongoing. Experimental treatments are being tested in clinical trials, and some preliminary results suggest that some drugs may reduce symptoms or extend life. But nothing is final. This field has been carefully studied and no breakthrough findings have been made that would change the fundamental outcome of this disease.
The GHB Exception and Experimental Avenues
Traditional sleeping pills have little effect on FFI. Sedatives used for common insomnia do not correct the underlying neurological damage. There is one notable exception: gamma hydroxybutyric acid (GHB).
GHB is a central nervous system depressant. It is sometimes used as a sleeping pill, but it is also known as a club drug. People with FFI may experience short periods of sleep. In addition, it appears to prevent excessive activity of the sympathetic nervous system. It temporarily relieves the body’s stress response by lowering heart rate and body temperature.
Other drugs have theoretical promise but lack strong evidence. Benzodiazepine antagonists such as flumazenil (often used to reverse sedative overdose) can temporarily relieve the confusion and dementia associated with FFI. Although it may seem counterintuitive that flumazenil blocks the effects of benzodiazepines, flumazenil may restore some cognitive clarity in cases where FFI-specific receptors are abnormal.
These treatments are experimental. They are not the standard of care. More research is needed to determine whether they provide real benefit or are just temporary illusions. For now, the window remains narrow, and the options limited.
