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  • Mitochondrial Dna Depletion Syndrome, Encephalomyopathic Form with Methylmalonic Aciduria

Disease at a Glance

Summary
Mitochondrial DNA depletion syndrome, encephalomyopathic form with methylmalonic aciduria (MTDPS9) affects the brain, nervous system, and muscles. Symptoms are different from person to person. They may include muscle weakness, hearing loss, and difficulty feeding and breathing. Other symptoms may include severe low muscle tone, developmental delay, and cognitive impairment. Symptoms usually begin in early infancy and get worse over time, often leading to death in infancy. MTDPS9 is caused by genetic variants in the SUCLG1 gene (also known as the SUCLA1 gene) and is inherited in an autosomal recessive pattern. Diagnosis is based on the symptoms, clinical exam, imaging studies, and the removal of a small piece of muscle for examination (muscle biopsy). The diagnosis may also be confirmed by the results of genetic testing.
Resource(s) for Medical Professionals and Scientists on This Disease:
  • RareSource offers rare disease gene variant annotations and links to rare disease gene literature.
  • GeneReviews  provides scientific information on genetic diseases, including diagnosis, treatment, and genetic counseling.

About Mitochondrial DNA depletion syndrome, encephalomyopathic form with methylmalonic aciduria

Many rare diseases have limited information. Currently GARD aims to provide the following information for this disease:

  • Population Estimate:Fewer than 1,000 people in the U.S. have this disease.
  • Symptoms:May start to appear as an Infant.
  • Cause:This condition is caused by a change in the genetic material (DNA).
  • Organizations:Patient organizations are available to help find a specialist, or advocacy and support for this specific disease.
  • Newborn Screening:This condition may be detected through routine newborn screening.
  • Categories:Gastrointestinal DiseaseInherited Metabolic DiseaseNeurological DiseaseGenetic Disease
When Do Symptoms of Mitochondrial DNA depletion syndrome, encephalomyopathic form with methylmalonic aciduria Begin?
Symptoms of this disease may start to appear as an Infant.

The age symptoms may begin to appear differs between diseases. Symptoms may begin in a single age range, or during several age ranges. The symptoms from some diseases may begin at any age. Knowing when symptoms began to appear can help medical providers find the correct diagnosis.
Prenatal
Before Birth
Newborn
Birth-4 weeks
Infant Selected
1-23 months
Child
2-11 years
Adolescent
12-18 years
Adult
19-65 years
Older Adult
65+ years
Symptoms may start to appear as an Infant.
This information comes from Orphanet

Symptoms

The number and severity of symptoms experienced may differ among people with this disease. Your experience may be different from others, and you should consult your primary care provider for more information.

This list is not all-inclusive, but the following symptoms have been linked to this disease:

19 Symptoms

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Medical Term

Abnormal electroretinogram

Frequency
Uncommon
Very frequent
Very frequent
Always
Description

Any abnormality of the electrical responses of various cell types in the retina as measured by electroretinography.

Any abnormality of the electrical responses of various cell types in the retina as measured by electroretinography.

Synonym

Abnormal electroretinography; Abnormal ERG; ERG abnormal

Abnormal electroretinography; Abnormal ERG; ERG abnormal

19 Symptoms
This information comes from the Human Phenotype Ontology (HPO)

Causes

Genetic Disease

Mitochondrial DNA depletion syndrome, encephalomyopathic form with methylmalonic aciduria is a genetic disease, which means that it is caused by one or more genes not working correctly.

Disease-causing variants, or differences, in the following gene(s) are known to cause this disease: SUCLA2

What Is a Gene?

Understanding what genes are and how changes in genes may affect the body can help you on the journey to diagnosis and treatment of a genetic disease.

Genes are part of our DNA, the basic genetic material found in each of our body's cells. Cells are the building blocks of all living things and specialized cells form our body's organs and tissues. DNA is found in the nucleus of a cell and, in humans, is packaged into 23 pairs of chromosomes with the help of special proteins.

Each gene performs a different job in our cells. Some genes serve as the instructions to make proteins. Proteins are needed for the structure, function, and regulation of the body's cells, tissues, and organs. Some genes can turn other genes on or off. Others make RNA molecules that are involved in chemical reactions in the body.

Sources to Learn More: What Is a Gene? (MedlinePlus); What Are Proteins and What Do They Do? (MedlinePlus)Understanding what genes are and how changes in genes may affect the body can help you on the journey to diagnosis and treatment of a genetic disease.

Genes are part of our DNA, the basic genetic material found in each of our body's cells. Cells are the building blocks of all living things and specialized cells form our body's organs and tissues. DNA is found in the nucleus of a cell and, in humans, is packaged into 23 pairs of chromosomes with the help of special proteins.

Each gene performs a different job in our cells. Some genes serve as the instructions to make proteins. Proteins are needed for the structure, function, and regulation of the body's cells, tissues, and organs. Some genes can turn other genes on or off. Others make RNA molecules that are involved in chemical reactions in the body.

Sources to Learn More: What Is a Gene? (MedlinePlus); What Are Proteins and What Do They Do? (MedlinePlus)
Read More
Inheritance

All individuals inherit two copies of most genes. The number of copies of a gene that need to have a disease-causing variant affects the way a disease is inherited. This disease is inherited in the following pattern(s):

Mitochondrial Inheritance

Mitochondria are structures in each cell that produce energy and each one contains a small amount of DNA. A mitochondrial disease occurs when a gene located in mitochondrial DNA has a disease causing (pathogenic) variant. Mutation is an older term that is still sometimes used to mean pathogenic variant.

Because only egg cells contribute mitochondria to the developing embryo, only women can pass on mitochondrial variants to their children. Diseases caused by pathogenic variants in mitochondrial DNA can appear in every generation of a family and in both men and women, but fathers do not pass these disorders to their daughters or sons.

If a child is the first person in a family with the mitochondrial disease, the pathogenic variant may have occurred by chance for the first time in the child's mitochondria (de novo).Mitochondria are structures in each cell that produce energy and each one contains a small amount of DNA. A mitochondrial disease occurs when a gene located in mitochondrial DNA has a disease causing (pathogenic) variant. Mutation is an older term that is still sometimes used to mean pathogenic variant.

Because only egg cells contribute mitochondria to the developing embryo, only women can pass on mitochondrial variants to their children. Diseases caused by pathogenic variants in mitochondrial DNA can appear in every generation of a family and in both men and women, but fathers do not pass these disorders to their daughters or sons.

If a child is the first person in a family with the mitochondrial disease, the pathogenic variant may have occurred by chance for the first time in the child's mitochondria (de novo).
Read More

Advocacy and Support Groups

How Can Patient Organizations Help?

Patient organizations can help patients and families connect. They build public awareness of the disease and are a driving force behind research to improve patients' lives. They may offer online and in-person resources to help people live well with their disease. Many collaborate with medical experts and researchers.

Services of patient organizations differ, but may include:

  • Ways to connect to others and share personal stories
  • Easy-to-read information
  • Up-to-date treatment and research information
  • Patient registries
  • Lists of specialists or specialty centers
  • Financial aid and travel resources

Please note: GARD provides organizations for informational purposes only and not as an endorsement of their services. Please contact an organization directly if you have questions about the information or resources it provides.

Patient Organizations

6 Organizations

Organization Name

Who They Serve

Helpful Links

Country

MitoAction
People With

Mitochondrial Dna Depletion Syndrome, Encephalomyopathic Form with Methylmalonic Aciduria

Helpful Links
Country

United States

United Mitochondrial Disease Foundation
People With

Mitochondrial Dna Depletion Syndrome, Encephalomyopathic Form with Methylmalonic Aciduria

Helpful Links
Country

United States

EveryLife Foundation for Rare Diseases
People With

Rare Diseases

Helpful Links
Country

United States

Genetic Alliance
People With

Rare Diseases

Helpful Links
Country

United States

Global Genes
People With

Rare Diseases

Helpful Links
Country

United States

National Organization for Rare Disorders
People With

Rare Diseases

Helpful Links
Country

United States

Participating in Clinical Studies

Clinical studies are part of clinical research and at the heart of all medical advances, including rare diseases. Participating in research helps researchers ultimately uncover better ways to treat, prevent, diagnose, and understand human diseases.

What Are Clinical Studies?

Clinical studies are medical research involving people as participants. There are two main types of clinical studies:

  1. Clinical trials determine if a new test or treatment for a disease is effective and safe by comparing groups receiving different tests/treatments.
  2. Observational studies involve recording changes over time among a specific group of people in their natural settings.
Learn more about the different types of clinical studies, consent forms, questions you should ask before participating in clinical studies, and the difference between research and medical treatment.

Why Participate in Clinical Studies?

People participate in clinical trials for a variety of reasons. Participants with a disease may participate to help others, but also to possibly receive the newest treatment and additional care from clinical study staff. Healthy volunteers may also participate to help others and to contribute to moving science forward.

How Do You Find the Right Clinical Study?

To find the right clinical study we recommend you:

  • Use ClincalTrials.gov button below to search for studies by disease, terms, or country.
  • Consult doctors, other trusted medical professionals, and patient organizations.
  • Enroll in databases to allow researchers from participating institutions to find you.

What if There Are No Available Clinical Studies?

ResearchMatch helps connect people interested in research studies with researchers from top medical centers across the United States. Anyone from the U.S. can register with this free program funded by NIH. Researchers from participating institutions use the database to search for and invite patients or healthy volunteers who meet their study criteria to participate.

What Are Clinical Studies?

Clinical studies are medical research involving people as participants. There are two main types of clinical studies:

  1. Clinical trials determine if a new test or treatment for a disease is effective and safe by comparing groups receiving different tests/treatments.
  2. Observational studies involve recording changes over time among a specific group of people in their natural settings.
Learn more about the different types of clinical studies, consent forms, questions you should ask before participating in clinical studies, and the difference between research and medical treatment.

Why Participate in Clinical Studies?

People participate in clinical trials for a variety of reasons. Participants with a disease may participate to help others, but also to possibly receive the newest treatment and additional care from clinical study staff. Healthy volunteers may also participate to help others and to contribute to moving science forward.

How Do You Find the Right Clinical Study?

To find the right clinical study we recommend you:

  • Use ClincalTrials.gov button below to search for studies by disease, terms, or country.
  • Consult doctors, other trusted medical professionals, and patient organizations.
  • Enroll in databases to allow researchers from participating institutions to find you.

What if There Are No Available Clinical Studies?

ResearchMatch helps connect people interested in research studies with researchers from top medical centers across the United States. Anyone from the U.S. can register with this free program funded by NIH. Researchers from participating institutions use the database to search for and invite patients or healthy volunteers who meet their study criteria to participate.

ClinicalTrials.gov, an affiliate of NIH, provides current information on clinical research studies in the United States and abroad. Talk to a trusted doctor before choosing to participate in any clinical study. We recommend checking this site often and searching for studies with related terms/synonyms to improve results.
Please contact GARD if you need help finding additional information or resources on rare diseases, including clinical studies. Our Information Specialists are available to you by phone or by filling out our contact form. Note, GARD cannot enroll individuals in clinical studies.
ClinicalTrials.gov, an affiliate of NIH, provides current information on clinical research studies in the United States and abroad. Talk to a trusted doctor before choosing to participate in any clinical study. We recommend checking this site often and searching for studies with related terms/synonyms to improve results.
Please contact GARD if you need help finding additional information or resources on rare diseases, including clinical studies. Our Information Specialists are available to you by phone or by filling out our contact form. Note, GARD cannot enroll individuals in clinical studies.

Learn about symptoms, cause, support, and research for a rare disease. 

Take steps toward getting a diagnosis by working with your doctor, finding the right specialists, and coordinating medical care.

Find resources for patients and caregivers that address the challenges of living with a rare disease.

Take steps toward getting a diagnosis by working with your doctor, finding the right specialists, and coordinating medical care.

Last Updated: February 2023