CAPOS syndrome is a rare genetic neurological disorder which is characterized by abnormalities of the feet, eyes and brain which affect their normal function. These symptoms occur episodically when a fever-related infection is present within the body.
Signs and symptoms
Usually, individuals with this condition have cerebellar ataxia,
areflexia
Hyporeflexia is the reduction or absence of normal bodily reflexes (areflexia). It can be detected through the use of a reflex hammer and is the opposite of hyperreflexia.
Hyporeflexia is generally associated with a deficit in the lower motor n ...
,
high-arched feet,
optic nerve wasting/degeneration, sensorineural
deafness
Deafness has varying definitions in cultural and medical contexts. In medical contexts, the meaning of deafness is hearing loss that precludes a person from understanding spoken language, an audiological condition. In this context it is written ...
.
These symptoms have variable onset, but they generally begin episodically after having a
fever
Fever, also referred to as pyrexia, is defined as having a temperature above the normal range due to an increase in the body's temperature set point. There is not a single agreed-upon upper limit for normal temperature with sources using val ...
-causing infection such as the
common cold, manifesting mainly as sudden-onset
ataxic episodes and
encephalopathy
Encephalopathy (; from grc, ἐνκέφαλος "brain" + πάθος "suffering") means any disorder or disease of the brain, especially chronic degenerative conditions. In modern usage, encephalopathy does not refer to a single disease, but ...
. Other triggers include
pregnancy
Pregnancy is the time during which one or more offspring develops ( gestates) inside a woman's uterus (womb). A multiple pregnancy involves more than one offspring, such as with twins.
Pregnancy usually occurs by sexual intercourse, but ...
and
giving birth
Childbirth, also known as labour and delivery, is the ending of pregnancy where one or more babies exits the internal environment of the mother via vaginal delivery or caesarean section. In 2019, there were about 140.11 million births globally ...
. Other symptoms that occur during the episodic ataxia includes
hypotonia
Hypotonia is a state of low muscle tone (the amount of tension or resistance to stretch in a muscle), often involving reduced muscle strength. Hypotonia is not a specific medical disorder, but a potential manifestation of many different diseases ...
,
nystagmus
Nystagmus is a condition of involuntary (or voluntary, in some cases) eye movement. Infants can be born with it but more commonly acquire it in infancy or later in life. In many cases it may result in reduced or limited vision. Due to the invol ...
,
strabismus
Strabismus is a vision disorder in which the eyes do not properly align with each other when looking at an object. The eye that is focused on an object can alternate. The condition may be present occasionally or constantly. If present during a ...
,
dysarthria
Dysarthria is a speech sound disorder resulting from neurological injury of the motor component of the motor–speech system and is characterized by poor articulation of phonemes. In other words, it is a condition in which problems effectivel ...
,
dysphagia
Dysphagia is difficulty in swallowing. Although classified under " symptoms and signs" in ICD-10, in some contexts it is classified as a condition in its own right.
It may be a sensation that suggests difficulty in the passage of solids or liqu ...
,
areflexia
Hyporeflexia is the reduction or absence of normal bodily reflexes (areflexia). It can be detected through the use of a reflex hammer and is the opposite of hyperreflexia.
Hyporeflexia is generally associated with a deficit in the lower motor n ...
/
hyporeflexia
Hyporeflexia is the reduction or absence of normal bodily reflexes (areflexia). It can be detected through the use of a reflex hammer and is the opposite of hyperreflexia.
Hyporeflexia is generally associated with a deficit in the lower motor n ...
, and temporary deafness. More serious symptoms include
loss of consciousness
Loss may refer to:
Arts, entertainment, and media Music
* ''Loss'' (Bass Communion album) (2006)
* ''Loss'' (Mull Historical Society album) (2001)
*"Loss", a song by God Is an Astronaut from their self-titled album (2008)
* Losses "(Lil Tjay son ...
and/or onset of a
coma
A coma is a deep state of prolonged unconsciousness in which a person cannot be awakened, fails to respond normally to painful stimuli, light, or sound, lacks a normal wake-sleep cycle and does not initiate voluntary actions. Coma patients exhi ...
.
These symptoms usually improve alongside the illness that caused the fever.
General frequency of episodes with people suffering from CAPOS syndrome is 1-3.
Complications
There are various complications associated with the disorder, some of them include
vision impairment
Visual impairment, also known as vision impairment, is a medical definition primarily measured based on an individual's better eye visual acuity; in the absence of treatment such as correctable eyewear, assistive devices, and medical treatment� ...
/blindness due to
optic atrophy Optic neuropathy is damage to the optic nerve from any cause. The optic nerve is a bundle of millions of fibers in the retina that sends visual signals to the brain.
Damage and death of these nerve cells, or neurons, leads to characteristic featu ...
characteristic of the disorder,
deafness
Deafness has varying definitions in cultural and medical contexts. In medical contexts, the meaning of deafness is hearing loss that precludes a person from understanding spoken language, an audiological condition. In this context it is written ...
due to atrophy of the nerves that aid in hearing, problems with walking due to the ataxia, etc.
Causes
This condition is caused by autosomal dominant
missense mutations
In genetics, a missense mutation is a point mutation in which a single nucleotide change results in a codon that codes for a different amino acid. It is a type of nonsynonymous substitution.
Substitution of protein from DNA mutations
Missense m ...
in the
ATP1A3
Sodium/potassium-transporting ATPase subunit alpha-3 is an enzyme that in humans is encoded by the ''ATP1A3'' gene.
Function
The protein encoded by this gene belongs to the family of P-type cation transport ATPases, and to the subfamily of ...
gene, in
chromosome 19
Chromosome 19 is one of the 23 pairs of chromosomes in humans. People normally have two copies of this chromosome. Chromosome 19 spans more than 58.6 million base pairs, the building material of DNA. It is considered the most gene-rich chromosom ...
. The mutation is thought to be gain-of-function.
Epidemiology
According to OMIM, only 14 cases have been described in medical literature.
History
This condition was first discovered in 1996 by Nicolaides et al. when they described a mother and two siblings (brother and sister) with (summarized) early-onset reoccurring cerebellar ataxia and progressive optic atrophy accompanied by sensorineural deafness.
References
{{reflist
Rare genetic syndromes
Syndromes with sensorineural hearing loss
Syndromes affecting the optic nerve
Autosomal dominant disorders
Episodic and paroxysmal disorders