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  3. Leigh syndrome, French Canadian type
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Leigh syndrome, French Canadian type


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Other Names:
Cox deficiency, French Canadian type; Cox deficiency, Saguenay Lac saint Jean type; Leigh syndrome, Saguenay Lac saint Jean type; Cox deficiency, French Canadian type; Cox deficiency, Saguenay Lac saint Jean type; Leigh syndrome, Saguenay Lac saint Jean type; LSFC; Cytochrome c oxidase deficiency, French Canadian type See More
Categories:
Congenital and Genetic Diseases; Eye diseases; Metabolic disorders; Congenital and Genetic Diseases; Eye diseases; Metabolic disorders; Nervous System Diseases See More
This disease is grouped under:
Leigh syndrome

Summary Summary


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The following summary is from Orphanet, a European reference portal for information on rare diseases and orphan drugs.
orphanet

Orpha Number: 70472

Definition
Saguenay-Lac-St. Jean (SLSJ) type congenital lactic acidosis, a French Canadian form of Leigh syndrome (see this term), is a mitochondrial disease characterized by chronic metabolic acidosis, hypotonia, facial dysmorphism and delayed development.

Epidemiology
The exact prevalence of this disorder is not known. It was first described in Saguenay-Lac-Saint-Jean (Quebec, Canada) where its prevalence at birth is estimated to be 1/2,000. In this region, the prevalence of the gene mutation underlying the disorder is estimated to be 1/23 inhabitants, and may be due to a founder effect.

Clinical description
Facial dysmorphism is characterized by a prominent forehead, wide nasal bridge, hypertelorism, broad anterior fontanelle, midfacial hypoplasia, broad midline, synophrys, and a characteristic arched form of the eyebrows, along with mild hirsutism. There are 3 forms of the disease corresponding to varying degrees of severity: a neonatal form, a classic form and a so-called "survivor" form. The neonatal form is characterized by fulminant acidotic states. The classic form can occur from birth with severe lactic acidosis, or manifest between 14 and 24 months by ataxic gait. This form is associated with episodes of lactic acidosis that can be triggered by physical exertion, emotional stress, infection or a heavy meal, and/or metabolic crises. Patients known as "survivors", i.e. those who have survived several episodes, cross a critical threshold and show less severe symptoms including hypotonia, asthenia, developmental delay (language acquisition and walking) and, in older patients, truncal ataxia, and a characteristic wide-based gait.

Etiology
SLSJ congenital lactic acidosis is caused by two types of mutations in the LRPPRC gene (2p21). The most frequent is a single A354V mutation. Only one patient has been identified as a heterozygous carrier of the A354V mutation and the C1277Xdel8 deletion of the same gene. LRPPRC codes for the leucine-rich pentatricopeptide repeat-containing protein and appears to be involved in the transport and stability of mature mitochondrial mRNA. Biochemically, the cytochrome C oxidase enzyme (COX) involved in the respiratory chain was found to be deficient in all patients, but other proteins in the respiratory chain may also be deficient.

Diagnostic methods
Diagnosis is based on determination of lactate levels in the blood and cerebrospinal fluid, determination of COX activity in fibroblasts, but is made primarily through identification of the A354V mutation, which confirms the diagnosis.

Differential diagnosis
Differential diagnoses include other forms of Leigh syndrome and other possible causes of metabolic acidosis such as MELAS syndrome, glucose-6-phosphate dehydrogenase (G6PD) deficiency, pyruvate dehydrogenase deficiency, and pyruvate carboxylase deficiency (see these terms).

Antenatal diagnosis
Since the discovery of the underlying mutations in 2003, prenatal diagnosis is offered to couples that have had an affected child.

Genetic counseling
The disease follows a monogenic autosomal recessive pattern of inheritance. Genetic counseling can be proposed to couples at risk through identification of heterozygous carriers.

Management and treatment
There is no specific treatment for the disease. A diet with a balanced intake of proteins, carbohydrates and lipids, spread evenly over the day, is recommended in order to reduce the high energy demands of digestion. Rest and strictly complying with the need for sleep are also beneficial.

Prognosis
In the neonatal form, the prognosis is very poor. In other patients, life expectancy is often less than 5 years due to severe episodes of acidosis.

Visit the Orphanet disease page for more resources.
Last updated: 12/1/2011

Symptoms Symptoms


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This table lists symptoms that people with this disease may have. For most diseases, symptoms will vary from person to person. People with the same disease may not have all the symptoms listed. This information comes from a database called the Human Phenotype Ontology (HPO) . The HPO collects information on symptoms that have been described in medical resources. The HPO is updated regularly. Use the HPO ID to access more in-depth information about a symptom.

Showing of 32 |
Medical Terms Other Names
Learn More:
HPO ID
5%-29% of people have these symptoms
Seizure 0001250
Percent of people who have these symptoms is not available through HPO
Anteverted nares
Nasal tip, upturned
Upturned nasal tip
Upturned nose
Upturned nostrils
[ more ]
0000463
Ataxia 0001251
Autosomal recessive inheritance 0000007
CNS demyelination 0007305
Delayed speech and language development
Deficiency of speech development
Delayed language development
Delayed speech
Delayed speech acquisition
Delayed speech development
Impaired speech and language development
Impaired speech development
Language delay
Language delayed
Language development deficit
Late-onset speech development
Poor language development
Speech and language delay
Speech and language difficulties
Speech delay
[ more ]
0000750
Failure to thrive
Faltering weight
Weight faltering
[ more ]
0001508
Generalized hypotonia
Decreased muscle tone
Low muscle tone
[ more ]
0001290
Gliosis 0002171
Global developmental delay 0001263
Highly arched eyebrow
Arched eyebrows
Broad, arched eyebrows
High, rounded eyebrows
High-arched eyebrows
Thick, flared eyebrows
[ more ]
0002553
Hirsutism
Excessive hairiness
0001007
Hyperglycemia
High blood sugar
0003074
Hypertelorism
Wide-set eyes
Widely spaced eyes
[ more ]
0000316
Hypoglycemia
Low blood sugar
0001943
Increased CSF lactate 0002490
Increased hepatocellular lipid droplets 0006565
Increased serum lactate 0002151
Infantile onset
Onset in first year of life
Onset in infancy
[ more ]
0003593
Lactic acidosis
Increased lactate in body
0003128
Low anterior hairline
Low frontal hairline
Low-set frontal hairline
[ more ]
0000294
Malar flattening
Zygomatic flattening
0000272
Microvesicular hepatic steatosis 0001414
Midface retrusion
Decreased size of midface
Midface deficiency
Underdevelopment of midface
[ more ]
0011800
Muscular hypotonia
Low or weak muscle tone
0001252
Peripheral demyelination 0011096
Prominent forehead
Pronounced forehead
Protruding forehead
[ more ]
0011220
Psychomotor retardation 0025356
Strabismus
Cross-eyed
Squint
Squint eyes
[ more ]
0000486
Tachypnea
Increased respiratory rate or depth of breathing
0002789
Tremor 0001337
Wide nasal bridge
Broad nasal bridge
Broad nasal root
Broadened nasal bridge
Increased breadth of bridge of nose
Increased breadth of nasal bridge
Increased width of bridge of nose
Increased width of nasal bridge
Nasal bridge broad
Wide bridge of nose
Widened nasal bridge
[ more ]
0000431
Showing of 32 |
Do you have more information about symptoms of this disease? We want to hear from you.
Last updated: 1/1/2021
Do you have updated information on this disease? We want to hear from you.

Diagnosis Diagnosis


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Making a diagnosis for a genetic or rare disease can often be challenging. Healthcare professionals typically look at a person’s medical history, symptoms, physical exam, and laboratory test results in order to make a diagnosis. The following resources provide information relating to diagnosis and testing for this condition. If you have questions about getting a diagnosis, you should contact a healthcare professional.

Testing Resources

  • The Genetic Testing Registry (GTR) provides information about the genetic tests for this condition. The intended audience for the GTR is health care providers and researchers. Patients and consumers with specific questions about a genetic test should contact a health care provider or a genetics professional.

Find a Specialist Find a Specialist


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If you need medical advice, you can look for doctors or other healthcare professionals who have experience with this disease. You may find these specialists through advocacy organizations, clinical trials, or articles published in medical journals. You may also want to contact a university or tertiary medical center in your area, because these centers tend to see more complex cases and have the latest technology and treatments.

If you can’t find a specialist in your local area, try contacting national or international specialists. They may be able to refer you to someone they know through conferences or research efforts. Some specialists may be willing to consult with you or your local doctors over the phone or by email if you can't travel to them for care.

You can find more tips in our guide, How to Find a Disease Specialist. We also encourage you to explore the rest of this page to find resources that can help you find specialists.

Healthcare Resources

  • To find a medical professional who specializes in genetics, you can ask your doctor for a referral or you can search for one yourself. Online directories are provided by the American College of Medical Genetics and the National Society of Genetic Counselors. If you need additional help, contact a GARD Information Specialist. You can also learn more about genetic consultations from Genetics Home Reference.

Research Research


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Research helps us better understand diseases and can lead to advances in diagnosis and treatment. This section provides resources to help you learn about medical research and ways to get involved.

Clinical Research Resources

  • The North American Mitochondrial Disease Consortium (NAMDC) is a team of doctors, nurses, research coordinators, and research labs throughout the U.S., working together to improve the lives of people with this condition through research.

Patient Registry

  • A registry supports research by collecting of information about patients that share something in common, such as being diagnosed with Leigh syndrome, French Canadian type. The type of data collected can vary from registry to registry and is based on the goals and purpose of that registry. Some registries collect contact information while others collect more detailed medical information. Learn more about registries.

    Registries for Leigh syndrome, French Canadian type:
    North American Mitochondrial Disease Consortium (NAMDC) Contact Registry
    People Against Leigh Syndrome Registry
     

Organizations Organizations


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Support and advocacy groups can help you connect with other patients and families, and they can provide valuable services. Many develop patient-centered information and are the driving force behind research for better treatments and possible cures. They can direct you to research, resources, and services. Many organizations also have experts who serve as medical advisors or provide lists of doctors/clinics. Visit the group’s website or contact them to learn about the services they offer. Inclusion on this list is not an endorsement by GARD.

Organizations Supporting this Disease

  • MitoAction
    PO Box 51474
    Boston, MA 02205
    Toll-free: 1-888-648-6228
    Telephone: 1-888-MITO-411 (648-6411) for support line
    E-mail: info@mitoaction.org
    Website: https://www.mitoaction.org/
  • People Against Leigh Syndrome (PALS)
    Lori Martin, Director
    Houston, TX,
    Telephone: 713-863-0485
    E-mail: director@peopleagainstleighs.org
    Website: http://peopleagainstleighs.org/
Do you know of an organization? We want to hear from you.

Learn More Learn More


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These resources provide more information about this condition or associated symptoms. The in-depth resources contain medical and scientific language that may be hard to understand. You may want to review these resources with a medical professional.

In-Depth Information

  • The Monarch Initiative brings together data about this condition from humans and other species to help physicians and biomedical researchers. Monarch’s tools are designed to make it easier to compare the signs and symptoms (phenotypes) of different diseases and discover common features. This initiative is a collaboration between several academic institutions across the world and is funded by the National Institutes of Health. Visit the website to explore the biology of this condition.
  • The Neuromuscular Disease Center at Washington University provides information about Leigh syndrome.
  • Online Mendelian Inheritance in Man (OMIM) is a catalog of human genes and genetic disorders. Each entry has a summary of related medical articles. It is meant for health care professionals and researchers. OMIM is maintained by Johns Hopkins University School of Medicine. 
  • Orphanet is a European reference portal for information on rare diseases and orphan drugs. Access to this database is free of charge.
  • PubMed is a searchable database of medical literature and lists journal articles that discuss Leigh syndrome, French Canadian type. Click on the link to view a sample search on this topic.

Selected Full-Text Journal Articles

  • Huntsman RJ, Sinclair DB, Bhargava R, Chan A. Atypical presentations of Leigh syndrome: A case series and review. Pediatr Neurol 2005;32:334-340.

GARD Answers GARD Answers


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Questions sent to GARD may be posted here if the information could be helpful to others. We remove all identifying information when posting a question to protect your privacy. If you do not want your question posted, please let us know.

Have a question? Contact a GARD Information Specialist.
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You can help advance rare disease research!
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