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Charlevoix-Saguenay spastic ataxia(SACS)

MedGen UID:
338620
Concept ID:
C1849140
Disease or Syndrome
Synonyms: Autosomal recessive spastic ataxia of Charlevoix-Saguenay; SACS; SPASTIC ATAXIA 6, AUTOSOMAL RECESSIVE; Spastic ataxia of Charlevoix-Saguenay
SNOMED CT: ARSACS - autosomal recessive spastic ataxia of Charlevoix-Saguenay (702445005); Autosomal recessive spastic ataxia of Charlevoix-Saguenay (702445005); Spastic ataxia of Charlevoix-Saguenay (702445005)
Modes of inheritance:
Autosomal recessive inheritance
MedGen UID:
141025
Concept ID:
C0441748
Intellectual Product
Sources: HPO, OMIM
A mode of inheritance that is observed for traits related to a gene encoded on one of the autosomes (i.e., the human chromosomes 1-22) in which a trait manifests in individuals with two pathogenic alleles, either homozygotes (two copies of the same mutant allele) or compound heterozygotes (whereby each copy of a gene has a distinct mutant allele).
 
Gene (location): SACS (13q12.12)
 
Monarch Initiative: MONDO:0010041
OMIM®: 270550
Orphanet: ORPHA98

Disease characteristics

Excerpted from the GeneReview: ARSACS
Autosomal recessive spastic ataxia of Charlevoix-Saguenay (ARSACS) is clinically characterized by a progressive cerebellar ataxia, peripheral neuropathy, and spasticity. Disease onset of classic ARSACS is often in early childhood, leading to delayed walking because of gait unsteadiness in very young toddlers, while an increasing number of individuals with disease onset in teenage or early-adult years are now being described. Typically the ataxia is followed by lower-limb spasticity and later by peripheral neuropathy – although pronounced peripheral neuropathy has been observed as a first sign of ARSACS. Oculomotor disturbances, dysarthria, and upper-limb ataxia develop with slower progression than the other findings. Brain imaging demonstrates atrophy of the superior vermis and the cerebellar hemisphere with additional findings on MRI, such as linear hypointensities in the pons and hyperintense rims around the thalami. Many affected individuals (though not all) have yellow streaks of hypermyelinated fibers radiating from the edges of the optic disc noted on ophthalmologic exam, and thickened retinal fibers can be demonstrated by optical coherence tomography. Mild intellectual disability, hearing loss, and urinary urgency and incontinence have been reported in some individuals. [from GeneReviews]
Authors:
Sascha Vermeer  |  Bart P van de Warrenburg  |  Erik-Jan Kamsteeg, et. al.   view full author information

Additional descriptions

From OMIM
Autosomal recessive spastic ataxia of Charlevoix-Saguenay is a complex neurodegenerative disorder usually characterized by early childhood onset of cerebellar ataxia, pyramidal tract signs, and peripheral neuropathy. Most patients become wheelchair-bound; cognitive function is usually not affected. Some patients may have atypical features, such as later onset or initial presentation of peripheral neuropathy (summary by Baets et al., 2010).  http://www.omim.org/entry/270550
From MedlinePlus Genetics
Autosomal recessive spastic ataxia of Charlevoix-Saguenay, more commonly known as ARSACS, is a condition affecting muscle movement. People with ARSACS typically have abnormal tensing of the muscles (spasticity), problems with balance and coordination (cerebellar ataxia), and reduced sensation and weakness in the arms and legs (peripheral neuropathy).\n\nAdditional muscle problems that can occur in ARSACS include muscle wasting (amyotrophy), involuntary eye movements (nystagmus), and difficulty swallowing (dysphagia) and speaking (dysarthria). Other features of ARSACS involve high-arched feet (pes cavus), a spine that curves to the side (scoliosis), yellow streaks of fatty tissue in the light-sensitive tissue at the back of the eye (hypermyelination of the retina), urinary tract problems, intellectual disability, hearing loss, and recurrent seizures (epilepsy).\n\nAn unsteady walking style (gait) is the first symptom of ARSACS. Walking problems usually begin between the ages of 12 months and 18 months, as toddlers are learning to walk. These movement problems worsen over time, with increased spasticity and ataxia of the arms and legs. In some cases spasticity goes away, but this apparent improvement is thought to be due to the wasting away (atrophy) of nerves in the arms and legs. Most affected individuals require wheelchair assistance by the time they are in their thirties or forties.\n\nWhile this condition was named after the area in which it was first seen, the Charlevoix-Saguenay region of Quebec, Canada, ARSACS has been identified in individuals worldwide.  https://medlineplus.gov/genetics/condition/autosomal-recessive-spastic-ataxia-of-charlevoix-saguenay

Clinical features

From HPO
Urinary urgency
MedGen UID:
39315
Concept ID:
C0085606
Finding
Urge incontinence is the strong, sudden need to urinate.
Absent Achilles reflex
MedGen UID:
108240
Concept ID:
C0558845
Finding
Absence of the Achilles reflex (also known as the ankle jerk reflex), which can normally be elicited by tapping the tendon is tapped while the foot is dorsiflexed.
Pes cavus
MedGen UID:
675590
Concept ID:
C0728829
Congenital Abnormality
The presence of an unusually high plantar arch. Also called high instep, pes cavus refers to a distinctly hollow form of the sole of the foot when it is bearing weight.
Hammertoe
MedGen UID:
209712
Concept ID:
C1136179
Anatomical Abnormality
Hyperextension of the metatarsal-phalangeal joint with hyperflexion of the proximal interphalangeal (PIP) joint.
Peroneal muscle atrophy
MedGen UID:
810815
Concept ID:
C1389118
Disease or Syndrome
Atrophy of the peroneous muscles, peroneus longus (also known as Fibularis longus), Peroneus brevis (also known as fibularis brevis, and Peroneus tertius (also known as fibularis tertius).
Swan neck-like deformities of the fingers
MedGen UID:
336516
Concept ID:
C1849152
Finding
A swan neck deformity describes a finger with a hyperextended PIP joint and a flexed DIP joint. The most common cause for a swan neck-like deformity is a disruption of the end of the extensor tendon. Conditions that loosen the PIP joint and allow it to hyperextend, for example conditions that weaken the volar plate, can produce a swan neck deformity of the finger. One example is rheumatoid arthritis. Another cause are conditions that tighten up the small (intrinsic) muscles of the hand and fingers, for example hand trauma or nerve disorders, such as cerebral palsy, Parkinson's disease, or stroke.
Cerebellar ataxia
MedGen UID:
849
Concept ID:
C0007758
Disease or Syndrome
Cerebellar ataxia refers to ataxia due to dysfunction of the cerebellum. This causes a variety of elementary neurological deficits including asynergy (lack of coordination between muscles, limbs and joints), dysmetria (lack of ability to judge distances that can lead to under- or overshoot in grasping movements), and dysdiadochokinesia (inability to perform rapid movements requiring antagonizing muscle groups to be switched on and off repeatedly).
Dysarthria
MedGen UID:
8510
Concept ID:
C0013362
Mental or Behavioral Dysfunction
Dysarthric speech is a general description referring to a neurological speech disorder characterized by poor articulation. Depending on the involved neurological structures, dysarthria may be further classified as spastic, flaccid, ataxic, hyperkinetic and hypokinetic, or mixed.
Spasticity
MedGen UID:
7753
Concept ID:
C0026838
Sign or Symptom
A motor disorder characterized by a velocity-dependent increase in tonic stretch reflexes with increased muscle tone, exaggerated (hyperexcitable) tendon reflexes.
Babinski sign
MedGen UID:
19708
Concept ID:
C0034935
Finding
A reflex characterized by upward movement of the great toe and an outward movement of the rest of the toes, when the sole of the foot is stroked. It is a normal reflex up to the age of two. Its presence beyond that age indicates neurological damage.
Falls
MedGen UID:
39084
Concept ID:
C0085639
Finding
A sudden movement downward, usually resulting in injury.
Hyperreflexia
MedGen UID:
57738
Concept ID:
C0151889
Finding
Hyperreflexia is the presence of hyperactive stretch reflexes of the muscles.
Spastic gait
MedGen UID:
115907
Concept ID:
C0231687
Finding
Spasticity is manifested by increased stretch reflex which is intensified with movement velocity. This results in excessive and inappropriate muscle activation which can contribute to muscle hypertonia. Spastic gait is characterized by manifestations such as muscle hypertonia, stiff knee, and circumduction of the leg.
Dysmetria
MedGen UID:
68583
Concept ID:
C0234162
Finding
A type of ataxia characterized by the inability to carry out movements with the correct range and motion across the plane of more than one joint related to incorrect estimation of the distances required for targeted movements.
Hyperactive patellar reflex
MedGen UID:
66003
Concept ID:
C0240116
Finding
Scanning speech
MedGen UID:
82928
Concept ID:
C0278184
Sign or Symptom
An abnormal pattern of speech in which the words are as if measured or scanned; there is a pause after every syllable, and the syllables themselves are pronounced slowly.
Absent Achilles reflex
MedGen UID:
108240
Concept ID:
C0558845
Finding
Absence of the Achilles reflex (also known as the ankle jerk reflex), which can normally be elicited by tapping the tendon is tapped while the foot is dorsiflexed.
Cerebellar vermis atrophy
MedGen UID:
149271
Concept ID:
C0742028
Finding
Wasting (atrophy) of the vermis of cerebellum.
Upper motor neuron dysfunction
MedGen UID:
333241
Concept ID:
C1839042
Pathologic Function
A functional anomaly of the upper motor neuron. The upper motor neurons are neurons of the primary motor cortex which project to the brainstem and spinal chord via the corticonuclear, corticobulbar and corticospinal (pyramidal) tracts. They are involved in control of voluntary movements. Dysfunction leads to weakness, impairment of fine motor movements, spasticity, hyperreflexia and abnormal pyramidal signs.
Progressive gait ataxia
MedGen UID:
375309
Concept ID:
C1843885
Finding
A type of gait ataxia displaying progression of clinical severity.
Distal sensory impairment
MedGen UID:
335722
Concept ID:
C1847584
Finding
An abnormal reduction in sensation in the distal portions of the extremities.
Onion bulb formation
MedGen UID:
376237
Concept ID:
C1847906
Finding
Repeated episodes of segmental demyelination and remyelination lead to the accumulation of supernumerary Schwann cells around axons, which is referred to as onion bulb formation. This finding affects peripheral nerves.
Impaired vibration sensation in the lower limbs
MedGen UID:
338617
Concept ID:
C1849134
Finding
A decrease in the ability to perceive vibration in the legs.
Progressive truncal ataxia
MedGen UID:
341389
Concept ID:
C1849143
Finding
Loss of Purkinje cells in the cerebellar vermis
MedGen UID:
336510
Concept ID:
C1849146
Finding
Decreased sensory nerve conduction velocity
MedGen UID:
336512
Concept ID:
C1849148
Finding
Reduced speed of conduction of the action potential along a sensory nerve.
Hypermyelinated retinal nerve fibers
MedGen UID:
336515
Concept ID:
C1849151
Finding
Spastic ataxia
MedGen UID:
376528
Concept ID:
C1849156
Disease or Syndrome
Decreased motor nerve conduction velocity
MedGen UID:
388130
Concept ID:
C1858729
Finding
A type of decreased nerve conduction velocity that affects the motor neuron.
Decreased number of large peripheral myelinated nerve fibers
MedGen UID:
395303
Concept ID:
C1859606
Finding
A reduced number of large myelinated nerve fibers.
Intellectual disability
MedGen UID:
811461
Concept ID:
C3714756
Mental or Behavioral Dysfunction
A broad category of disorders characterized by an impairment to the intelligence an individual possesses. These impairments can result from trauma, birth, or disease and are not restricted to any particular age group.
Spasticity
MedGen UID:
7753
Concept ID:
C0026838
Sign or Symptom
A motor disorder characterized by a velocity-dependent increase in tonic stretch reflexes with increased muscle tone, exaggerated (hyperexcitable) tendon reflexes.
Scoliosis
MedGen UID:
11348
Concept ID:
C0036439
Disease or Syndrome
The presence of an abnormal lateral curvature of the spine.
Spastic gait
MedGen UID:
115907
Concept ID:
C0231687
Finding
Spasticity is manifested by increased stretch reflex which is intensified with movement velocity. This results in excessive and inappropriate muscle activation which can contribute to muscle hypertonia. Spastic gait is characterized by manifestations such as muscle hypertonia, stiff knee, and circumduction of the leg.
Distal muscle weakness
MedGen UID:
140883
Concept ID:
C0427065
Finding
Reduced strength of the musculature of the distal extremities.
Hammertoe
MedGen UID:
209712
Concept ID:
C1136179
Anatomical Abnormality
Hyperextension of the metatarsal-phalangeal joint with hyperflexion of the proximal interphalangeal (PIP) joint.
Peroneal muscle atrophy
MedGen UID:
810815
Concept ID:
C1389118
Disease or Syndrome
Atrophy of the peroneous muscles, peroneus longus (also known as Fibularis longus), Peroneus brevis (also known as fibularis brevis, and Peroneus tertius (also known as fibularis tertius).
Distal amyotrophy
MedGen UID:
338530
Concept ID:
C1848736
Disease or Syndrome
Muscular atrophy affecting muscles in the distal portions of the extremities.
Swan neck-like deformities of the fingers
MedGen UID:
336516
Concept ID:
C1849152
Finding
A swan neck deformity describes a finger with a hyperextended PIP joint and a flexed DIP joint. The most common cause for a swan neck-like deformity is a disruption of the end of the extensor tendon. Conditions that loosen the PIP joint and allow it to hyperextend, for example conditions that weaken the volar plate, can produce a swan neck deformity of the finger. One example is rheumatoid arthritis. Another cause are conditions that tighten up the small (intrinsic) muscles of the hand and fingers, for example hand trauma or nerve disorders, such as cerebral palsy, Parkinson's disease, or stroke.
Nystagmus
MedGen UID:
45166
Concept ID:
C0028738
Disease or Syndrome
Rhythmic, involuntary oscillations of one or both eyes related to abnormality in fixation, conjugate gaze, or vestibular mechanisms.
Impaired smooth pursuit
MedGen UID:
325176
Concept ID:
C1837458
Finding
An impairment of the ability to track objects with the ocular smooth pursuit system, a class of rather slow eye movements that minimizes retinal target motion.
Hypermyelinated retinal nerve fibers
MedGen UID:
336515
Concept ID:
C1849151
Finding

Term Hierarchy

CClinical test,  RResearch test,  OOMIM,  GGeneReviews,  VClinVar  
  • CROGVCharlevoix-Saguenay spastic ataxia
Follow this link to review classifications for Charlevoix-Saguenay spastic ataxia in Orphanet.

Professional guidelines

PubMed

van de Warrenburg BP, van Gaalen J, Boesch S, Burgunder JM, Dürr A, Giunti P, Klockgether T, Mariotti C, Pandolfo M, Riess O
Eur J Neurol 2014 Apr;21(4):552-62. Epub 2014 Jan 13 doi: 10.1111/ene.12341. PMID: 24418350

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