• Methylmalonic Acidemia

Diagnostic Journey

Here, discover the type of medical professionals that can help, tools for finding them, and tips for getting the most out of your care as you navigate to a diagnosis. The process of getting a rare disease diagnosis can take several years. Finding the right medical professionals to collect and make sense of your medical information can be challenging. Diagnosis may come through a primary care provider, or after specialized testing and referrals. Though the challenges are similar, everyone’s diagnostic journey is different because everyone’s story is too.

Your Medical Team

What should I expect when building a medical team?

Building a medical team can help speed diagnosis and improve medical care. The primary care provider (PCP) is usually the center of the team. Your health care providers may refer you to other specialists for evaluation and treatment of developing symptoms. Your medical team may change as your medical needs change over time.

Understanding which doctors treat which body systems can help you find the best care for your disease.

Members of the medical team for Methylmalonic acidemia may include:

A primary care provider (PCP) serves as the first line of care. PCPs diagnose and treat common conditions, manage a patient’s overall health, and provide referrals to specialists. Types of PCPs include doctors practicing general medicine, family practice, pediatrics, internal medicine, and geriatrics. Nurse practitioners and physician assistants may also serve as PCPs.

Find government-funded primary care services through HRSA Find a Health Center (directory by the Health Resources and Services Administration).

Find a pediatrician in your area for patients 21 and younger (directory by the American Academy of Pediatrics).

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Additional specialists may include:

Allergists / Immunologists are trained to diagnose, treat, and manage diseases that affect the immune system. The immune system protects the body against harmful substances. Allergists/Immunologists commonly treat patients with asthma, allergies, and chronic infections. They use blood tests and skin tests to identify substances which can trigger an immune response. They often prescribe medications to treat allergies or infections.

Find an allergist / immunologist in your area (directory by the American Academy of Allergy, Asthma, & Immunology).

Heart doctors (cardiologists) are trained to diagnose, treat, and manage diseases that affect the heart and blood vessels. Cardiologists commonly use monitors to track heart activity and imaging to look directly at the heart and blood vessels. Cardiologists may suggest specific lifestyle changes as a form of treatment. In some cases, cardiologists will perform surgery to correct physical defects of the heart or implant devices to manage heart activity.

Find a cardiologist in your area (directory by Medicare).

Skin doctors (dermatologists) are trained to diagnose, treat, and manage diseases that affect the skin, hair, and nails. Dermatologists can learn a lot about the body by examining the skin. They commonly treat skin infections, hair loss, rashes, eczema, and skin cancer. Dermatologists may collect skin samples to help diagnose a condition. Medications, radiation, UV light therapy, and surgery may be used as treatments.

Find a dermatologist in your area (directory by the American Academy of Dermatology Association).

Endocrinologists are trained to diagnose, treat, and manage diseases related to hormones. Hormones help coordinate the body’s activities. Endocrinologists commonly treat patients with conditions such as diabetes, thyroid disorders, and certain cancers. They also treat patients with concerns about growth or sexual development. Endocrinologists may use medications, hormone therapy, or surgery to treat patients.

Find an endocrinologist in your area (directory by the Endocrine Society).

Gastrointestinal (GI) specialists (gastroenterologists) are trained to diagnose, treat, and manage diseases that affect the digestive system. The digestive system includes the esophagus, stomach, intestines, pancreas, gallbladder, and liver. Gastroenterologists commonly use flexible tubes with built-in cameras to examine the inside of the digestive tract.

Find a gastroenterologist in your area (directory by the American College of Gastroenterology).

Genetic specialists (geneticists) are trained to diagnose, treat, and manage patients with genetic changes, birth defects, or metabolic disorders. Metabolic disorders result from changes in the way a person’s body makes or uses energy. Along with genetic counselors, geneticists commonly discuss family history, genetic risks, genetic testing options, and genetic test results.

Find a genetic specialist in your area (directory by the American College of Medical Genetics and Genomics).

Blood system doctors (hematologists) are trained to diagnose, treat, and manage diseases that affect the blood and the bone marrow (where blood cells are made). They also treat certain diseases of the lymphatic system (spleen and lymph tissues) which maintains fluid levels and protects the body from infection. Hematologists treat anemia, bleeding disorders, blood clotting disorders, and blood cancers. They often order blood tests or bone marrow biopsies to help them learn more about a person’s condition.

Find a hematologist in your area (directory by the American Society of Hematology).

Infectious disease doctors are trained to diagnose, treat, and manage diseases caused by bacteria, viruses, fungi, or parasites. They can test a sample of the infected tissue to help diagnose the specific infection and to determine the best treatment. Treatment may include medications that can be taken by mouth, injected, inserted directly into a vein (intravenous), or applied to the skin.

Please consult your primary care doctor for help finding an infectious disease specialist.

Mouth, jaw, and face surgeons (maxillofacial surgeons) are trained to diagnose, treat, and manage conditions involving the mouth, teeth, jaw, face, and neck. They commonly treat patients with dental problems and cancers of the head and neck. They also treat patients with injuries to the mouth, jaw, and face. Maxillofacial surgeons may operate to reduce pain, repair injuries, improve appearance, and restore or improve function.

Find a maxillofacial surgeon in your area (directory by the American Association of Oral and Maxillofacial Surgeons).

Kidney doctors (nephrologists) are trained to diagnose, treat, and manage diseases that affect the kidneys. Kidney conditions may also affect blood pressure or fluid and mineral balances in the body. Nephrologists commonly treat patients with kidney stones, kidney infections, chronic kidney disease, and kidney failure. They may order blood tests, urine tests, and imaging studies to diagnose diseases of the kidneys and to monitor how well treatments are working. They can also help manage the impact of kidney conditions on the rest of the body.

Please consult your primary care doctor for help finding a nephrologist.

Neurologists are trained to diagnose, treat, and manage diseases that affect the nervous system. The nervous system controls the body’s functions and is made up of the brain, spinal cord, and nerves. Neurologists commonly treat patients with thinking and memory issues, seizures, movement disorders, and muscular dystrophies. Neurologists often order tests that measure electrical activity or tests that provide images of the inside of the brain or spine.

Please consult your primary care doctor for help finding a neurologist.

Women’s health doctors (obstetricians/gynecologists or Ob-Gyns) are trained to diagnose and treat diseases of the female reproductive system. Gynecology involves the care of a woman’s reproductive organs and health. Obstetrics involves the care of women during pregnancy and birth. Ob-Gyns commonly order tests to monitor pregnancies and to help with the early detection, prevention, and management of conditions such as endometriosis, cysts, and cancer.

Find a gynecologist / obstetrician in your area (directory by the American College of Obstetricians and Gynecologists).

Cancer doctors (oncologists) are trained to diagnose, treat, and manage cancers and conditions that could become cancerous over time. They commonly work with a team of healthcare providers to manage care. Oncologists often specialize in a specific type of cancer such as breast cancer or colon cancer. Treatments suggested by oncologists may include surgery, chemotherapy, radiation, or treatments that help a person’s immune system fight cancer (immunotherapy).

Find an oncologist in your area (directory by the American Society of Clinical Oncology).

Eye doctors (ophthalmologists) are trained to diagnose, treat, and manage diseases of the eye. They can treat all eye and vision conditions including those needing surgery. Both ophthalmologists and optometrists are an important part of a vision care team, but ophthalmologists have additional training.

Find an ophthalmologist in your area (directory by the American Academy of Ophthalmology).

Bone doctors (orthopedists or orthopedic surgeons) are trained to diagnose, treat, and manage diseases of the bones, muscles, tendons, ligaments, and joints. Orthopedists may manage patients using surgical or non-surgical techniques. They can treat sports injuries, arthritis, scoliosis, and broken bones. They commonly order tests to help identify the specific injury or condition. They also help patients who are in pain or who have trouble moving.

Find an orthopedist in your area (directory by the American Academy of Orthopaedic Surgeons).

Ear, nose, and throat (ENT) doctors (otolaryngologists) are trained to diagnose, treat, and manage diseases of the head and neck, especially those involving the ear, nose, and throat. Otolaryngologists can help patients with infections, swallowing issues, hearing and balance issues, and cancer. Treatments performed by otolaryngologists may include surgical or non-surgical techniques.

Find an otolaryngologist in your area (directory by the American Academy of Otolaryngology-Head and Neck Surgery).

Mental health specialists (psychiatrists) are trained to diagnose, treat, and manage diseases that affect mental, emotional, and behavioral health. Like other mental health professionals, psychiatrists can provide therapy to address emotional and behavioral issues. Because psychiatrists are medical doctors, they can also prescribe medications when needed.

Find a psychiatrist in your area (directory by the American Psychiatric Association).

Lung and breathing doctors (pulmonologists) are trained to diagnose, treat, and manage diseases of the lungs and airways. They commonly use blood tests, breathing tests, imaging, and sleep studies to make a diagnosis. Pulmonologists may use medications or exercise and breathing techniques (known as lung rehabilitation) to treat diseases of the lung.

Please consult your primary care doctor for help finding a pulmonologist.

Rheumatologists are doctors trained to diagnose, treat, and manage diseases of inflammation caused when the body’s immune system does not work properly. Autoimmune diseases and autoinflammatory diseases are often treated by rheumatologists. Rheumatologists commonly use biopsy, blood tests, heart and muscle function tests, and a variety of imaging tests to diagnose these diseases. Rheumatologists may use medications that calm the body's immune system, physical therapy, occupational therapy, and regular monitoring to manage these conditions.

Find a rheumatologist in your area (directory by the American College of Rheumatology).

Surgical doctors (surgeons) are trained to diagnose, treat, and manage conditions that may require surgery. They commonly remove and repair damaged tissue or organs. Surgeons can also perform operations that help doctors learn more about a condition.

Find a surgeon in your area (directory by the American College of Surgeons).

Urinary system doctors (urologists) are trained to diagnose, treat, and manage diseases affecting the urinary tract of both males and females. The urinary tract includes the kidneys, ureters, and bladder. Urologists also manage conditions affecting the reproductive system of males. Urologists commonly treat urinary tract infections, kidney stones, bladder control problems, prostate problems, and cancer. They may use medications or surgery to treat patients.

Find a urologist in your area (directory by the American Urological Association).

Circulatory system doctors (vascular medicine specialists) are trained to diagnose, treat, and manage diseases involving the vessels that move blood around the body (arteries, veins, and capillaries). Vascular medicine specialists also manage diseases involving the lymphatic system which maintains fluid levels in the body and protects the body from infection. Vascular medicine specialists commonly use clinical exams, imaging tests, and blood tests to diagnose diseases. They can manage blood vessel disorders using diet, exercise, medication, and surgery.

Please consult your primary care doctor for help finding a vascular medicine specialist.

Appointments and Diagnostic Evaluations

Your relationship with your doctor is personal. Finding a doctor you can trust to provide you with the best options and course of treatment is a critical part of your health journey. To begin building this relationship, be prepared to share your medical history and that of your family members. Doctors will ask for this information, usually at the first visit. It is important to write down:
  • When your symptoms began
  • How the symptoms changed over time
  • Previous doctor visits and tests
  • Any treatments that have been tried.
The following tools may help you gather the information you need:

Milestone Tracker App [CDC]

Tracks a child's milestones from age 2 months to 5 years with Center for Disease Control and Prevention's (CDC) easy-to-use illustrated checklists. Also offers tips from CDC for encouraging a child's development and what to do if a parent or guardian is ever concerned about how their child is developing.

Patient's Toolkit for Diagnosis [Society to Improve Diagnosis in Medicine]

Provides a downloadable set of prompts and questions to help encourage participation and partnership with medical professionals. The Patient's Toolkit was designed for patients visiting their healthcare provider to help tell their story clearly.

Family History Tool [CDC]

Explains the importance of collecting family health history and sharing family health history with doctors. Also provides links to tools to help collect family history. 

Your relationship with your doctor is personal. Finding a doctor you can trust to provide you with the best options and course of treatment is a critical part of your health journey. To begin building this relationship, be prepared to share your medical history and that of your family members. Doctors will ask for this information, usually at the first visit. It is important to write down:
  • When your symptoms began
  • How the symptoms changed over time
  • Previous doctor visits and tests
  • Any treatments that have been tried.
The following tools may help you gather the information you need:

Milestone Tracker App [CDC]

Tracks a child's milestones from age 2 months to 5 years with Center for Disease Control and Prevention's (CDC) easy-to-use illustrated checklists. Also offers tips from CDC for encouraging a child's development and what to do if a parent or guardian is ever concerned about how their child is developing.

Patient's Toolkit for Diagnosis [Society to Improve Diagnosis in Medicine]

Provides a downloadable set of prompts and questions to help encourage participation and partnership with medical professionals. The Patient's Toolkit was designed for patients visiting their healthcare provider to help tell their story clearly.

Family History Tool [CDC]

Explains the importance of collecting family health history and sharing family health history with doctors. Also provides links to tools to help collect family history. 

It's important to set goals for your visit and write down the questions you have before your appointment. Decide beforehand which questions are most important to have answered. Preparing a list of symptoms most affecting your quality of life may also help to focus the conversation.

For more information, visit the following:

Question Builder App [AHRQ]

Explains how the App helps patients and caregivers prepare for medical appointments and maximize visit time. Links to download the free App are also provided.

Talking With Your Doctor or Health Care Provider [NIH]

Includes three short videos about preparing for a doctors visit, talking openly with a doctor, and understanding diagnosis and treatment. Also provides links to other resources to help patients and families play an active role in their health care.

Talking With Your Doctor [MedlinePlus]

Offers tips and more resources to improve communication with a doctor during a medical visit.

Mental health support is available for patients and caregivers who are coping with the stress that can come with having a rare disease. The National Alliance on Mental Illness offers guidance on the different types of mental health professionals.

APA Psychologist Locator
Your level of comfort with a psychologist is important. Talking with them about their services can help you find someone with whom you feel at ease. Use the American Psychological Association tool, your location, and the Refine Search menu to find local options. The psychologist’s practice areas, treatment methods, licensure, and contact information is provided. 

Find a Therapist
Rare patients and caregivers may find counselors and therapists specializing in chronic illness, stress, or grief to be helpful. The types of therapy offered will vary depending on the therapist's specific training program. Use the Psychology Today's Therapy Directory menus to refine your search.

Find a Psychiatrist
Psychiatrists are medical doctors that diagnose, treat, and manage diseases that affect mental, emotional, and behavioral health. They can provide therapy and prescribe medications. Psychiatrists can be hard to find in some areas. Using the American Psychiatric Association tool you may need to expand your mile radius or search by state. Primary care doctors and insurance companies can also help you explore options.

Once your health care provider gathers some basic information such as your medical history and any previous diagnoses, they will perform a physical exam.

During the physical exam, the health care provider will look for physical signs of a medical problem, such as pain and swelling or the presence of liquid or solid masses within the body. The methods used during the exam may differ, depending on the symptoms, but are common and routine procedures.

Depending on the information gathered and the results of the physical exam, your health care provider may recommend specific lab tests, such as a blood draw; imaging studies, such as an X-ray or MRI; or clinical procedures, such as a hearing test. If any of your symptoms worsen or change after your physical exam, it is important to follow-up with your health care provider.
Once your health care provider gathers some basic information such as your medical history and any previous diagnoses, they will perform a physical exam.

During the physical exam, the health care provider will look for physical signs of a medical problem, such as pain and swelling or the presence of liquid or solid masses within the body. The methods used during the exam may differ, depending on the symptoms, but are common and routine procedures.

Depending on the information gathered and the results of the physical exam, your health care provider may recommend specific lab tests, such as a blood draw; imaging studies, such as an X-ray or MRI; or clinical procedures, such as a hearing test. If any of your symptoms worsen or change after your physical exam, it is important to follow-up with your health care provider.
Newborn screening is a set of tests performed on newborns, usually before leaving the hospital. The specific tests performed vary somewhat by state. However, in every state, the tests screen for at least 30 genetic diseases, hearing impairment, and congenital heart defects.

Based on the results of the newborn screen, further testing may be needed. With early diagnosis, treatment for the diseases identified in newborn screening can begin right away before serious problems occur or become permanent.

The newborn screening tests performed in your state may include screening for this disease. You can learn more about newborn screening diseases, follow-up testing, and treatments by visiting the following:

Newborn Screening in Your State [HRSA]

Provides information for families and health professionals about newborn screening in the United States in English and Spanish, including:

  • An overview of the newborn screening process, results, and follow-up
  • A list of conditions that are screened in each state
  • Contact information for each state's newborn screening program

Baby's First Test

Provides information in English and Spanish for families and health professionals about newborn health screening in the United States. Fact sheets are available for each state, including a list of conditions screened and contact information for related programs and services. There are also fact sheets on each covered condition, including early signs, treatment, expected outcomes, and cause.

A genetic test may be ordered by your PCP, a geneticist, or other specialist to confirm or rule out a diagnosis. A genetic test looks for changes in a person's DNA that may cause a disease or medical symptom.
If your doctor recommends genetic testing, and you consent, a sample of blood, saliva, or other tissue will be collected and analyzed. It can take several weeks for results to be returned.

Your healthcare professional can best help you understand your test results, including if the test found the cause of the disease. Depending on the type of genetic test and the results, additional genetic testing may be recommended.
In many cases, health care providers may recommend clinical procedures be performed to help determine a diagnosis. Clinical procedures may include a range of different tests depending on your body system being evaluated.

Procedures may be performed by a variety of health care providers, including nurses, physician's assistants and lab technicians, before results are reviewed by your doctor. In many cases, clinical procedures performed on the path to a diagnosis will be out-patient procedures that are likely to require a referral from your PCP.

Learn more about clinical procedures your doctor may recommend.
Laboratory (lab) tests may be ordered by your health care provider to check a sample of your blood, urine, or body tissues to help diagnose your disease. The type of lab tests ordered will depend on your symptoms and the diseases being considered.

Learn more about the type(s) of lab tests your health care provider may recommend.
Talk to a doctor to learn if any imaging studies are suggested to diagnose or manage this disease.

Diagnostic imaging studies let doctors look inside a patient's body for clues to help diagnose or manage a disease. The type of imaging study a doctor chooses depends on a patient's symptoms and the part of the body being examined.

If a doctor recommends an imaging study, additional information about the study may be available on Diagnostic Imaging [MedlinePlus].

Care Coordination

Coordination between patients, caregivers, and providers is important. Medical care is safer and more effective when your providers actively communicate with you and each other. Good coordination within your team can prevent unnecessary medical tests and can lead to better outcomes. You may need to sign consent for release forms to allow your providers to communicate with each other, so it is helpful to keep a list of providers and their contact information.

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Care Coordinator Approach

Often, multiple specialists are needed to diagnose and care for a person with a rare disease. Communication between doctors can shorten the time to a diagnosis and ensure that a care plan meets all of your needs. Primary care providers (PCPs) usually serve as care coordinators. They maintain medical records and share information with different specialists.

In some cases, a patient or caregiver may take on the role of care coordinator. Resources provided by patient organizations can help patients or caregivers navigate this role.

Find a primary care provider in your area using Care Compare 'Doctors & clinicians' by typing in your zip code and selecting "General practice" as the specialty (directory by the Centers for Medicare & Medicaid Services).

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Integrated Approach

In some instances, a team of professionals that work together at a research or teaching hospital may be used to holistically care for your disease rather than coordinating care among individual specialists from different locations.

These hospitals tend to be associated with universities or research facilities and usually have the latest technologies that may not be found in standard hospitals/clinics.

Find hospitals in your area using Care Compare 'Hospitals' by typing in your zip code (directory by the Centers for Medicare & Medicaid Services).

Rare Disease Experts

How can I find an expert?

It can be hard to find experts as there may only be a few in your state, region, or country. Experts often work at large research or teaching hospitals. These hospitals rely on a group of experts, often with diverse training. Experts can help when a diagnosis remains unknown despite extensive efforts.

You can ask your medical providers for help finding an expert. You can also use directory tools to search.

The following organization maintains a listing of expert centers for a broad range of rare diseases:
Salesforce Alt Text

Rare Disease Experts

How can I find an expert?
Salesforce Alt Text

It can be hard to find experts as there may only be a few in your state, region, or country. Experts often work at large research or teaching hospitals. These hospitals rely on a group of experts, often with diverse training. Experts can help when a diagnosis remains unknown despite extensive efforts.

You can ask your medical providers for help finding an expert. You can also use directory tools to search.

The following organization maintains a listing of expert centers for a broad range of rare diseases:

Advocate for Yourself

Maintaining open and honest communication with your health care providers will prove crucial to helping you get the most out of the healthcare system, regardless of where you find yourself on the path to diagnosis.

For Those Who Have a Diagnosis

While a diagnosis may come as a relief, it can also come with questions and concerns. Though many rare diseases do not have a cure, research is ongoing and new treatments are constantly being developed. Even when a cure does not exist, specific symptoms can often be managed. Connecting with other patients who have received the same diagnosis can be a great source of information, resources, and support.

GARD lists patient organizations on our rare disease pages.

For Those With a Working Diagnosis

A working diagnosis means the doctor has a good idea about the cause of a patient's symptoms, but not enough evidence to say for certain. Monitoring changes in a patient’s health and responses to various treatments may offer further clues. It is important to track new and ongoing symptoms, follow the management plan, and continue meeting regularly with the doctors. Additional testing and referrals may be needed to make a firm diagnosis. 

Working Diagnosis: Discuss What Happens Next by Asking These Key Questions (Society to Improve Diagnosis in Medicine)

For Those Who Are Still Undiagnosed

Some will remain undiagnosed despite an extensive medical evaluation. Many doctors have limited experience diagnosing rare diseases. In addition, rare diseases can have symptoms that are hard to detect or that may have many possible causes. In some cases, patients may have more than one condition. It is very important to keep meeting with the doctors. More tests and specialist referrals may be needed. Research opportunities and programs focused on the undiagnosed may offer additional ways to solve medical mysteries.

Contact GARD for help finding resources for the undiagnosed.

Please contact GARD if you need help finding additional information or resources on rare diseases.

Contact Us

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.

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

Last Updated: February 2023