Disease at a Glance

Summary
Spinal muscular atrophy 1 (SMA1), also known as Werdnig Hoffmann disease, is a genetic neuromuscular disorder that affects the nerve cells that control voluntary muscles (motor neurons). Without treatment, symptoms of SMA1 become apparent before 6 months of age and include worsening muscle weakness and poor muscle tone (hypotonia) due to loss of the lower motor neurons in the spinal cord and brain stem. Feeding and breathing problems may also present. SMA1 is caused by changes (pathogenic variants also called genetic changes) in the SMN1 gene and is typically inherited in an autosomal recessive manner. Diagnosis of SMA1 is suspected by symptoms and confirmed by genetic testing. SMA has been added to the list of recommended newborn screening tests in the United States, so that it can be detected prior to symptoms developing.

About Spinal muscular atrophy 1

Many rare diseases have limited information. Currently GARD is able to provide the following information for Spinal muscular atrophy 1:

  • Population Estimate:In the US, there are less than 5,000 with this disease.
  • Symptoms:May start to appear as a Newborn and as an Infant.
  • Experts:Patient organizations are available to help find a specialist for this condition.
  • Organizations:Organizations specific to this condition are available to help find support. 

When do symptoms of this disease begin?
The most common ages for symptoms of a disease to begin is called age of onset. Age of onset can vary for different diseases and may be used by a doctor to determine the diagnosis. For some diseases, symptoms may begin in a single age range or several age ranges. For other diseases, symptoms may begin any time during a person's life.
Prenatal
Before Birth
Newborn Selected
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 a Newborn and as an Infant.

Symptoms

This information is currently in development. 

Causes

Genetic Disease

Spinal muscular atrophy 1 is a genetic disease, which means that it is caused by one or more genes not working correctly.

Disease causing variants in the following gene(s) are known to cause this disease: SMN1

What is a gene?

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's a Gene? (NHGRI) ; What are proteins and what do they do? (MedlinePlus)
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's a Gene? (NHGRI) ; 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):

Autosomal recessive inheritance

Autosomal means the gene is located on any chromosome except the X or Y chromosomes (sex chromosomes). Genes, like chromosomes, usually come in pairs. Recessive means that both copies of the responsible gene must have a disease-causing change (pathogenic variant) in order for a person to have the disease. Mutation is an older term that is still sometimes used to mean pathogenic variant.

A person who has an autosomal recessive disease receives a gene with a pathogenic variant from each of their parents. Each parent is a carrier which means they have a pathogenic variant in only one copy of the gene. Carriers of an autosomal recessive disease usually do not have any symptoms of the disease. When two carriers of an autosomal recessive disease have children, there is a 25% (1 in 4) chance to have a child who has the disease.
Autosomal means the gene is located on any chromosome except the X or Y chromosomes (sex chromosomes). Genes, like chromosomes, usually come in pairs. Recessive means that both copies of the responsible gene must have a disease-causing change (pathogenic variant) in order for a person to have the disease. Mutation is an older term that is still sometimes used to mean pathogenic variant.

A person who has an autosomal recessive disease receives a gene with a pathogenic variant from each of their parents. Each parent is a carrier which means they have a pathogenic variant in only one copy of the gene. Carriers of an autosomal recessive disease usually do not have any symptoms of the disease. When two carriers of an autosomal recessive disease have children, there is a 25% (1 in 4) chance to have a child who has the disease.
Read More

Advocacy and Support Groups

How can a patient organization be helpful?

Patient advocacy and support organizations offer many valuable services and often drive the research and development of treatments for their disease(s). Because these organizations include the life experiences of many different people who have a specific disease, they may best understand the resources needed by those in their community. Although missions of organizations may differ, services may include, but are not limited to:
 

  • Ways to connect to others and share personal stories
  • Easy-to-read information
  • Latest treatment and research information
  • Lists of specialists or specialty centers
  • Financial aid and travel resources
Please note: GARD provides the names of patient organizations for informational purposes only and not as an endorsement of their services. Please contact the organization directly if you have questions about the information or resources they provide.

What do disease-specific organizations do?

Some organizations build a community of patients and families impacted by a specific disease or group of related diseases. These organizations usually have more disease-specific information and services, including helping new members find others who have the same disease.

What do organizations that focus on a medical condition do?

Some organizations build a community of patients and families impacted by a medical condition, like epilepsy, or related conditions, like heart problems, that may also be a symptom in other diseases. These organizations usually have information and services focused more on the medical condition(s), but may also have information about associated diseases.

What do umbrella organizations do?

Rare disease umbrella organizations focus on improving the lives of all those impacted by rare diseases through education and advocacy efforts. Umbrella organizations provide a range of services for patients, families, and disease-specific organizations.

Patient Organizations

10 Organizations

Organization Name

Organization Type

Service

Country

Language

Spinal Muscular Atrophy Association of Australia Inc.
https://smaaustralia.org.au/
Disease Specific

Spinal Muscular Atrophy 1

Service

Information

Country

Australia

Language

English

Gwendolyn Strong Foundation
https://nevergiveup.org/
Disease Specific

Spinal Muscular Atrophy 1

Service

Information

Country

United States

Language

English

Cure SMA Canada
https://curesma.ca/
Disease Specific

Spinal Muscular Atrophy 1

Service

Information

Country

Canada

Language

English

French

Spinal Muscular Atrophy Foundation
https://smafoundation.org/
Disease Specific

Spinal Muscular Atrophy 1

Service

Information

Research

Country

United States

Language

English

Disease Specific

Spinal Muscular Atrophy 1

Service

Information

Research

Country

United States

Language

English

Muscular Dystrophy Association
https://www.mda.org
Disease Specific

Spinal Muscular Atrophy 1

Service

Information

Research

Specialist

Country

United States

Language

English

EveryLife Foundation for Rare Diseases
https://everylifefoundation.org/
Umbrella

Spinal Muscular Atrophy 1

Service

Information

Country

United States

Language

English

Spanish

Umbrella

Spinal Muscular Atrophy 1

Service

Information

Country

United States

Language

English

Umbrella

Spinal Muscular Atrophy 1

Service

Information

Country

United States

Language

English

National Organization for Rare Disorders
https://rarediseases.org/
Umbrella

Spinal Muscular Atrophy 1

Service

Information

Research

Country

United States

Language

English

Spanish

10 Organizations

Research

Why is Research Important for Rare Diseases?

Research increases what we know about rare diseases so that people can get a diagnosis more quickly and can know what to expect. Research also helps doctors better understand how well a treatment works and can lead to new treatment discoveries. It may even help improve diagnosis and treatment of more common diseases.

How do you find the right clinical study?

  • Discuss the clinical study with a trusted medical provider before enrolling
  • Review the "Study Description," which discusses the purpose of the study, and "Eligibility Criteria," which lists who can and cannot participate in the study
  • Work with the research coordinator to review the written informed consent, including the risks and benefits of the study
  • Inquire about the specific treatments and procedures, location of the study, number of visits, and time obligation
  • Determine whether health insurance is required and whether there are costs to the participant for the medical care, travel, and lodging
  • Ask questions. Remember, it is okay to decide not to participate in research

For More Information

Current clinical studies can be found by using ClincalTrials.gov. Doctors, other trusted medical professionals, and patient organizations may also be aware of studies. Researchers from participating institutions use the database to search for patients or healthy volunteers who meet their study criteria.

How do you find the right clinical study?

  • Discuss the clinical study with a trusted medical provider before enrolling
  • Review the "Study Description," which discusses the purpose of the study, and "Eligibility Criteria," which lists who can and cannot participate in the study
  • Work with the research coordinator to review the written informed consent, including the risks and benefits of the study
  • Inquire about the specific treatments and procedures, location of the study, number of visits, and time obligation
  • Determine whether health insurance is required and whether there are costs to the participant for the medical care, travel, and lodging
  • Ask questions. Remember, it is okay to decide not to participate in research

For More Information

Current clinical studies can be found by using ClincalTrials.gov. Doctors, other trusted medical professionals, and patient organizations may also be aware of studies. Researchers from participating institutions use the database to search for patients or healthy volunteers who meet their study criteria.

Last Updated: Nov. 8, 2021