Cardiology

The Biology of 'Molecular Glue'

At a Glance

Carvajal syndrome results from changes in the DSP gene, which weakens desmoplakin, a protein that helps cells stay connected. This can cause woolly hair, thickened skin on the palms and soles, and heart muscle disease, making genetic evaluation and lifelong cardiac monitoring important.

To understand Carvajal syndrome, it helps to think of the body as a building. For a building to stay standing, its bricks must be held together by high-quality mortar. In the human body, the “bricks” are your cells, and the “mortar” is a structure called a desmosome.

The Body’s ‘Molecular Glue’

Desmosomes are specialized patches that act like rivets or glue, pinning cells together so they can withstand pulling, stretching, and mechanical stress ^[1]. Inside these desmosomes is a critical protein called desmoplakin, which is produced by the DSP gene ^[2].

In Carvajal syndrome, a mutation in the DSP gene means the body doesn’t make enough functional desmoplakin, or the protein it does make is shaped incorrectly. This weakens the “glue” ^[3]. When the glue is weak, cells can pull apart or fail to communicate properly, leading to the symptoms seen in the skin, hair, and heart ^[4]^[5]. While this is a helpful analogy, desmosome biology is complex, and the tissue-specific phenotype reflects inflammatory and fibrotic mechanisms, not solely mechanical pulling.

Why These Specific Organs?

You may wonder why a genetic change affects the hair, skin, and heart but leaves most other organs alone. These three areas share a common need: they are under constant mechanical pressure ^[6].

The Skin: Your palms and soles are constantly rubbed, pressed, and stretched. Without strong desmosomes, the skin tries to protect itself by overproducing cells, leading to the thick, calloused palmoplantar keratoderma ^[4]^[7].
The Hair: The cells that form hair shafts also rely on desmoplakin to stay organized. When the glue is weak, the hair grows in a tightly coiled, “woolly” fashion from birth ^[8]^[9].
The Heart: The heart is a muscle that never stops “stretching” as it pumps blood. When the desmosomes in the heart muscle are weak, the constant mechanical stress causes the muscle cells to pull apart over time. This leads to inflammation, scarring (fibrosis), and a weakening of the heart’s pumping chambers ^[5]^[10].

Carvajal Syndrome vs. Naxos Disease

Carvajal syndrome is often confused with a very similar condition called Naxos disease. While they look almost identical on the outside, they have different biological drivers and typical cardiac patterns:

Feature	Carvajal Syndrome	Naxos Disease
Genetic Cause	DSP gene (Desmoplakin) ^[2]	JUP gene (Plakoglobin) ^[11]
Main Heart Target	Typically Left Ventricle (but can be biventricular) ^[9]	Typically Right Ventricle (but can be biventricular) ^[11]
Heart Condition	Dilated Cardiomyopathy (enlarged/weak) ^[7]	Arrhythmogenic Right Ventricular Cardiomyopathy ^[11]
Skin/Hair	Woolly hair & thick skin ^[7]	Woolly hair & thick skin ^[11]

In Carvajal syndrome, the left ventricle (the heart’s primary powerhouse) is usually the first to show signs of trouble, often becoming stretched and thin (dilated) ^[9]. In Naxos disease, the right ventricle is typically the primary focus, though both conditions can eventually affect the entire heart ^[7]^[12].

Confirming the Diagnosis

Doctors use several layers of evidence to confirm a diagnosis of Carvajal syndrome and rule out other similar disorders:

The Clinical Triad: The combination of woolly hair, thickened skin on the hands and feet, and signs of heart weakness is the strongest clinical indicator ^[7].
Genetic Testing: By analyzing the DSP gene, doctors can confirm pathogenic variants and distinguish Carvajal from Naxos or other similar syndromes ^[13]^[14]. However, a Variant of Uncertain Significance (VUS) or a negative test does not automatically rule out the disorder without clinical context.
Cardiac Imaging: Tools like an echocardiogram (ultrasound) or a cardiac MRI are used to see which side of the heart is affected and to look for tissue patterns of scarring ^[15]^[16].

Understanding that this is a “glue” problem helps explain why lifelong monitoring is necessary. Even if the heart looks healthy today, the underlying genetic structure requires regular check-ups to ensure the “building” remains strong as your child grows ^[17]^[8].

Common questions in this guide

What causes Carvajal syndrome?

Carvajal syndrome is caused by disease-causing changes in both copies of the DSP gene, which provides instructions for desmoplakin. Desmoplakin helps cells stay connected, so reduced or abnormal protein can affect the skin, hair, and heart. The condition is inherited in an autosomal recessive pattern.

Why does Carvajal syndrome affect the hair, skin, and heart?

These tissues depend heavily on strong connections between cells and experience repeated mechanical stress. When desmoplakin is not working well, the skin may become thick on the palms and soles, hair may grow in a woolly pattern, and heart muscle may develop inflammation, scarring, and weakness.

How is Carvajal syndrome different from Naxos disease?

Carvajal syndrome is usually caused by a DSP gene change and typically affects the left ventricle, the heart's main pumping chamber, causing dilated cardiomyopathy. Naxos disease is associated with JUP gene changes and more often affects the right ventricle. Either condition can involve both sides of the heart, and both can cause woolly hair and thickened skin.

How do doctors diagnose Carvajal syndrome?

Doctors look for the combination of woolly hair, thickened skin on the hands and feet, and signs of heart disease. DSP genetic testing can identify a pathogenic variant, while an echocardiogram or cardiac MRI can show heart enlargement, weakness, or scarring. A negative test or a variant of uncertain significance does not by itself rule out the condition; results are interpreted with the clinical findings.

Does a normal heart test mean my child no longer needs follow-up?

No. A child's heart may look normal today even when the underlying DSP-related cell-connection problem is present. Regular cardiac check-ups help doctors detect changes early as the child grows and should be planned with the child's care team.

Should siblings be tested for Carvajal syndrome if they have no obvious symptoms?

Because Carvajal syndrome is inherited in an autosomal recessive pattern, siblings may have inherited relevant DSP variants even without obvious woolly hair or skin changes. A genetic counselor can review the family's results and recommend testing or heart evaluation when appropriate.

Get notified when new evidence is published on Carvajal syndrome.

We monitor PubMed for new peer-reviewed studies on this topic and email a short summary when something meaningful changes.

References (17)

1
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2
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3
Functional investigation of two simultaneous or separately segregating DSP variants within a single family supports the theory of a dose-dependent disease severity.
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4
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5
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PMID: 36818425
6
Dsp rul: a spontaneous mouse mutation in desmoplakin as a model of Carvajal-Huerta syndrome.
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Experimental and molecular pathology 2015; (98(2)):164-72.
PMID: 25659760
7
Two Novel Homozygous Desmoplakin Mutations in Carvajal Syndrome.
Molho-Pessach V, Sheffer S, Siam R, et al.
Pediatric dermatology 2015; (32(5)):641-6 doi:10.1111/pde.12541.
PMID: 25824144
8
Combination of palmoplantar keratoderma and hair shaft anomalies, the warning signal of severe arrhythmogenic cardiomyopathy: a systematic review on genetic desmosomal diseases.
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9
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PMID: 40260958
10
Desmoplakin Cardiomyopathy, a Fibrotic and Inflammatory Form of Cardiomyopathy Distinct From Typical Dilated or Arrhythmogenic Right Ventricular Cardiomyopathy.
Smith ED, Lakdawala NK, Papoutsidakis N, et al.
Circulation 2020; (141(23)):1872-1884 doi:10.1161/CIRCULATIONAHA.119.044934.
PMID: 32372669
11
Cardiocutaneous syndrome (Naxos disease) in a Bangladeshi boy.
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12
A case of Carvajal syndrome presenting with dilated cardiomyopathy.
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Cardiology in the young 2024; (34(5)):1131-1133 doi:10.1017/S1047951124000222.
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13
A truncating variant altering the extreme C-terminal region of desmoplakin (DSP) suggests the crucial functional role of the region: a case report study.
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14
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15
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16
DSP c.6310delA p.(Thr2104Glnfs*12) associates with arrhythmogenic cardiomyopathy, increased trabeculation, curly hair, and palmoplantar keratoderma.
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17
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This page is for informational purposes only and does not constitute medical advice. A genetic counselor and cardiologist should interpret your child's DSP results and create an individualized monitoring plan.