Connective tissues, made up of collagen and elastin, hold other tissues and organs in the body together. Connective tissue diseases are various medical conditions that affect these tissues. When a person has a connective tissue disease (CTD), the connective tissues become inflamed, which can harm the parts of the body the tissues connect. There are many different types of CTDs, including:
This article is about the last two types of connective tissue disease: mixed connective tissue disease and undifferentiated connective tissue disease. (Visit the above links for articles about the other types of CTDs.)
Mixed connective tissue disease (MCTD) is a rare autoimmune disorder that's often called an "overlap disease," because it's a medical condition that has obvious symptoms of two or more connective tissue diseases. For example, a patient might have symptoms of systemic lupus and systemic vasculitis but blood tests that confirm rheumatoid arthritis.
Generally, overlap syndromes aren't as common as single connective tissue diseases; for example, mixed connective tissue disease occurs at 1/20th the rate of lupus. Mixed connective tissue disease can occur in people at any age, but it's more common in women under 50.
People with mixed connective tissue disease have symptoms in common with those who have other connective tissue diseases, including lupus, scleroderma, and rheumatoid arthritis. The most common symptoms include:
A few indicators can point to mixed connective tissue disorder rather than a single connective tissue disorder like lupus or rheumatoid arthritis, such as:
Patients with MCTD may meet the diagnoses for several connective diseases at the same time.
Undifferentiated connective tissue disease (UCTD) can have similar symptoms to MCTD, but it's not an overlap syndrome. UCTD has vague characteristics of one or more connective tissue diseases but doesn't actually meet enough of the criteria to be diagnosed as one of the other types of connective tissue diseases.
The most common symptoms that people with undifferentiated connective tissue disease experience include:
For approximately 20% to 40% of people with undifferentiated connective tissue disease, the symptoms progress to a more defined connective tissue disease, usually within three years. Another 10% to 30% of people with UCTD will experience remission of their symptoms, and the remainder will continue to experience the mostly mild symptoms of the disease.
Undifferentiated and mixed connective tissue diseases are both autoimmune disorders, where the immune system mistakenly attacks the body's own healthy tissues. The cause of undifferentiated or mixed connective tissue disease isn't usually known, but some connective tissue disease may be caused by:
A diagnosis of mixed connective tissue disorder or undifferentiated connective tissue disorder is not enough to get disability benefits. But if you're experiencing moderate to severe limitations that prevent you from working for 12 months or more, and you have good medical records, the Social Security Administration ("Social Security") may approve you for benefits.
Social Security has two ways you can qualify for disability benefits:
Social Security may evaluate your condition under listing 14.06, for "undifferentiated and mixed connective tissue disease." The listing states that you must have:
Meeting the criteria explained in this listing requires good medical evidence from your doctors.
You must have a medical diagnosis of a severe condition that's backed up by medical findings like lab tests, not just your reports about fatigue or feeling unwell. Social Security will evaluate your claim based on medical evidence like lab tests, CT scan results, and your doctors' treatment notes. Social Security might also send you for an independent exam by one of their doctors or might ask your doctor to complete a questionnaire about your limitations.
To get approved for disability for mixed or undifferentiated connective tissue disease, your records must include the following:
Most disability claims that are approved for benefits don't actually meet the criteria of one of the listings contained in Social Security's blue book. Instead, Social Security approves them because the applicants' limitations make them unable to perform their previous jobs and they're unable to transition into another type of work.
To decide whether you're unable to work, Social Security will look at your medical records to see if there's enough evidence you have a serious medical condition that limits your ability to do many work-related activities. A claims examiner will first determine your residual functional capacity (RFC), which is the most intensive work you can still do (medium, light, or sedentary), despite the limitations caused by your medical condition. For example, if you have severe undifferentiated or mixed connective tissue disease, your doctor might limit you to standing or walking a certain number of hours per day. You might also experience an aching pain and swelling in your joints, as well as numbness in your hands or toes, that could prevent you from doing finger work or lifting heavy items.
An RFC for someone suffering from severe MCTD or UCTD might include the following limitations:
Someone with these limitations would likely be unable to perform most jobs, because they would be unable to perform most of the physical requirements of even sit-down work. For more information on how the SSA decides whether your RFC prevents you from doing any jobs, see our section on disability determinations based on RFCs.
An easy way to apply for Social Security disability benefits is to file your claim online at www.ssa.gov/applyfordisability. You may also file a claim over the phone by contacting Social Security at 800-772-1213, but be prepared for long wait times. For more information, please see our article about applying for Social Security disability benefits
If you have questions or you'd like help with your application, click for a free case evaluation with a legal professional to determine if your vision problems qualify for benefits.
Published November 30, 2021
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