iSymptom

ConditionHormones & metabolism

Carney Complex

Carney complex (CNC) is a rare inherited condition that causes spotty skin pigmentation, benign tumors called myxomas (most importantly in the heart), and tumors of hormone-producing glands that can cause Cushing syndrome, acromegaly or thyroid nodules. Most cases are caused by changes in the PRKAR1A gene and are passed down in an autosomal dominant pattern. There is no cure, but regular screening finds heart myxomas and hormone problems early, when they are treatable.

Also called: CNC, Carney syndrome, LAMB syndrome (older term), NAME syndrome (older term)

By the iSymptom editorial team · Updated · 5 min read

At a glance

What it is
A rare inherited syndrome of skin pigmentation, myxomas and endocrine tumors.
Cause
Usually a change in the PRKAR1A gene. Inherited in 70% of cases, new in about 30%.
Key features
Lentigines (freckle-like spots) on the lips, eyelids and genitals, heart myxomas, PPNAD (Cushing syndrome), and thyroid, pituitary and testicular tumors.
Biggest risk
Heart myxomas, which can cause stroke, heart failure or sudden death.
Management
Yearly screening with echocardiograms and hormone tests, and surgery for tumors.

When to get help

Call 911 or go to the ER

  • Sudden weakness, numbness, speech difficulty or vision loss (possible stroke from a heart myxoma)
  • Fainting, especially when changing position, or sudden severe breathlessness (possible myxoma blocking a heart valve)

See a doctor within a day or two

  • New breathlessness, palpitations, unexplained fever, weight loss or a new heart murmur in someone with Carney complex
  • Rapid weight gain, purple stretch marks, high blood pressure or easy bruising (possible Cushing syndrome)

Book a routine appointment

  • Many small brown or black spots on the lips, eyelids, inside the mouth or on the genitals, especially if appearing in childhood
  • A family member with Carney complex, a heart myxoma, or Cushing syndrome from small adrenal nodules
  • A lump in the testicle, breast or thyroid
  • Growth of hands, feet or jaw in an adult

What causes Carney complex

About 70% of people with Carney complex have a disease-causing variant in PRKAR1A on chromosome 17. This gene helps regulate a cell signaling pathway (protein kinase A). When it does not work, cells in the skin, heart and hormone glands grow more than they should.

The condition is autosomal dominant: a person with Carney complex has a 50% chance of passing it to each child. About 30% of cases arise from a new variant with no family history. A smaller number of families have changes in other genes.

Signs and symptoms

Features vary greatly, even within the same family, and develop over time.

Skin

  • Lentigines: small brown to black flat spots, appearing around puberty, on the face (especially the lips, eyelids and inner corners of the eyes), inside the mouth and on the genitals. They are the most common feature.
  • Blue nevi: blue-black moles.
  • Cutaneous myxomas: small, soft, skin-colored bumps on the eyelids, ears, nipples or genitals.
  • Café-au-lait spots.

Heart

Cardiac myxomas are benign tumors that grow inside the heart chambers. They affect a large proportion of people with Carney complex, can occur at any age, can be in any chamber, and often recur. They can:

  • block blood flow, causing breathlessness, fainting or heart failure
  • shed fragments that travel to the brain, causing stroke
  • cause fever, weight loss and joint pains

They are the main cause of illness and death in Carney complex, which is why regular screening is essential.

Hormone glands

  • Primary pigmented nodular adrenocortical disease (PPNAD): small pigmented nodules in both adrenal glands that produce excess cortisol, causing Cushing syndrome, often in teenagers and young adults. Symptoms may be mild or cyclical.
  • Pituitary tumors: excess growth hormone can cause acromegaly (enlarged hands, feet and facial features).
  • Thyroid nodules and occasionally thyroid cancer. See thyroid nodules.
  • Testicular tumors: large-cell calcifying Sertoli cell tumors, usually benign, sometimes affecting fertility.
  • Ovarian cysts.

Other tumors

  • Psammomatous melanotic schwannoma: nerve sheath tumors, often near the spine or in the gut, which can occasionally be malignant.
  • Breast myxomas and ductal adenomas.
  • Osteochondromyxoma: a rare bone tumor.

Diagnosis

Carney complex is diagnosed when a person has at least 2 major features, or 1 major feature plus a PRKAR1A variant or an affected first-degree relative. Major features include typical lentigines, cutaneous or cardiac myxomas, PPNAD, acromegaly, Sertoli cell tumors, thyroid tumors, schwannomas, blue nevi and breast tumors.

Testing includes:

  • Genetic testing for PRKAR1A, which also allows testing of relatives
  • Echocardiogram to look for myxomas
  • Hormone tests: cortisol testing (urine free cortisol, late-night saliva, dexamethasone suppression), IGF-1 and prolactin
  • Imaging: thyroid and testicular ultrasound, adrenal CT, pituitary MRI as indicated

Screening and treatment

There is no treatment for the underlying gene change. Care focuses on finding and treating tumors early.

  • Echocardiogram: every 6 months in infancy, then at least yearly for life, and twice yearly in people who have had a myxoma removed
  • Yearly hormone tests: cortisol, IGF-1 and prolactin from puberty
  • Testicular ultrasound in boys, starting in childhood
  • Thyroid ultrasound at baseline and as needed
  • Pelvic ultrasound in women
  • MRI for schwannomas when symptoms suggest them

Treatment of tumors

  • Cardiac myxomas: prompt surgical removal. Regular follow-up afterward because new myxomas can form.
  • PPNAD: removal of both adrenal glands, followed by lifelong steroid hormone replacement. Some people are managed with medicines that block cortisol production.
  • Pituitary tumors: surgery, medicines or radiotherapy.
  • Thyroid, testicular and breast tumors: surgery or monitoring depending on size and behavior.
  • Skin lesions: generally harmless, removed if bothersome.

Outlook

Life expectancy is reduced on average, mainly because of heart myxomas, schwannomas and complications of Cushing syndrome. With regular screening and early surgery, many people live well into adulthood. Genetic counseling helps families plan and identifies relatives who need screening.

Frequently asked questions

What is Carney complex?

Carney complex is a rare inherited syndrome that causes freckle-like skin spots, benign tumors called myxomas in the heart and skin, and tumors of hormone glands that can lead to Cushing syndrome, acromegaly and thyroid or testicular nodules.

What gene causes Carney complex?

About 70% of cases are caused by variants in the PRKAR1A gene on chromosome 17. Some families have changes in other genes, and in some people no gene change is found despite typical features.

Is Carney complex inherited?

Yes, in about 70% of cases it is inherited from a parent in an autosomal dominant pattern, meaning each child of an affected person has a 50% chance of inheriting it. About 30% of cases are new in the affected person.

Why are heart myxomas dangerous in Carney complex?

Heart myxomas can block blood flow inside the heart, causing fainting, breathlessness or heart failure, and pieces can break off and cause strokes. They can recur, so people with Carney complex need regular echocardiograms for life.

How is Carney complex treated?

There is no cure. Treatment focuses on regular screening for heart, hormone and other tumors, and surgery to remove them. Cushing syndrome from adrenal nodules is usually treated by removing both adrenal glands.

Sources

This guide was written from current patient and clinical guidance, including:

  • MedlinePlus Genetics: Carney complex
  • NIH Genetic and Rare Diseases Information Center: Carney complex
  • Endocrine Society: Clinical practice guidelines on Cushing syndrome
  • Correa R, Salpea P, Stratakis CA, European Journal of Endocrinology: Carney complex, an update
  • GeneReviews (NCBI): Carney Complex