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Disease Profile

Ichthyosis hystrix, Curth Macklin type

Prevalence estimates on Rare Medical Network websites are calculated based on data available from numerous sources, including US and European government statistics, the NIH, Orphanet, and published epidemiologic studies. Rare disease population data is recognized to be highly variable, and based on a wide variety of source data and methodologies, so the prevalence data on this site should be assumed to be estimated and cannot be considered to be absolutely correct.

<1 / 1 000 000

US Estimated

Europe Estimated

Age of onset






Autosomal dominant A pathogenic variant in only one gene copy in each cell is sufficient to cause an autosomal dominant disease.


Autosomal recessive Pathogenic variants in both copies of each gene of the chromosome are needed to cause an autosomal recessive disease and observe the mutant phenotype.


dominant X-linked dominant inheritance, sometimes referred to as X-linked dominance, is a mode of genetic inheritance by which a dominant gene is carried on the X chromosome.


recessive Pathogenic variants in both copies of a gene on the X chromosome cause an X-linked recessive disorder.


Mitochondrial or multigenic Mitochondrial genetic disorders can be caused by changes (mutations) in either the mitochondrial DNA or nuclear DNA that lead to dysfunction of the mitochondria and inadequate production of energy.

Multigenic or multifactor Inheritance involving many factors, of which at least one is genetic but none is of overwhelming importance, as in the causation of a disease by multiple genetic and environmental factors.


Not applicable


Other names (AKA)

Curth-Macklin type ichthyosis hystrix; IHCM


Congenital and Genetic Diseases; Skin Diseases


The following summary is from Orphanet, a European reference portal for information on rare diseases and orphan drugs.

Orpha Number: 79503

Ichthyosis hystrix of Curth-Macklin (IHCM) is a rare type of keratinopathic ichthyosis (see this term) that is characterized by the presence of severe hyperkeratotic lesions and palmoplantar keratoderma (PPK, see this term).

Prevalence is unknown. Six families and sporadic cases have been reported to date.

Clinical description
The skin is usually normal at birth. The disease starts in early childhood with severe hyperkeratosis of yellow-brown or grey color, and of spiky, cobblestone-like (hystrix) or verrucous appearance. Hyperkeratosis is often diffuse and more pronounced on extensor areas of the limbs, extremities and the trunk. Lesions may also be nevoid following the lines of Blaschko. Patients are also affected with striate or diffuse PPK. As the disease progresses, PPK worsens and results in deep bleeding, painful fissures and cracks. In severe cases, PPK can also lead to contractures, gangrene and loss of digits. The skin is malodorous and frequently infected. Nail dystrophy may be present. Contrary to other keratinopathic ichthyoses, no skin fragility/blister formation or erythroderma is present.

IHCM results from heterozygous frameshift mutation in a section of the KRT1 gene encoding keratin 1 (K1). These mutations lead to an abnormal supramolecular organization of keratin intermediate filaments and may be related to defects in cytoplasmic trafficking and integrity of cellular structures such as organelles and nucleus.

Diagnostic methods
Diagnosis is based on clinical examination and on histological examination of skin lesion biopsies revealing papillomatous hyperplasia with hyperorthokeratosis and hypergranulosis. Electron microscopy shows keratin intermediate filaments forming continuous perinuclear shells, presence of perinuclear vacuoles and binucleate keratinocytes.

Differential diagnosis
Differential diagnosis includes other forms of keratinopathic ichthyosis such as epidermolytic ichthyosis, as well as epidermolytic palmoplantar keratoderma, erythrokeratodermia variabilis, and KID syndrome (see these terms).

Antenatal diagnosis
Molecular prenatal diagnosis is available for affected families.

Genetic counseling
Transmission is autosomal dominant but some sporadic cases have been reported. The risk for an affected parent to have an affected child is of 50%.

Management and treatment
Management is symptomatic and life-long. Oral and systemic keratolytics can improve localized hyperkeratotic lesions by exfoliating and increasing the moisture of the skin.

Life expectancy is normal. However, the unaesthetic and malodorous aspects of the skin, the pain and bleeding related to PPK, and infections lead to functional disabilities and a greatly reduced quality of life.

Visit the Orphanet disease page for more resources.


This table lists symptoms that people with this disease may have. For most diseases, symptoms will vary from person to person. People with the same disease may not have all the symptoms listed. This information comes from a database called the Human Phenotype Ontology (HPO) . The HPO collects information on symptoms that have been described in medical resources. The HPO is updated regularly. Use the HPO ID to access more in-depth information about a symptom.

Medical Terms Other Names
Learn More:
80%-99% of people have these symptoms
Diffuse palmoplantar keratoderma
Recurrent skin infections
Skin infections, recurrent
30%-79% of people have these symptoms
Flexion contracture
Flexed joint that cannot be straightened
Nail dystrophy
Poor nail formation
5%-29% of people have these symptoms
Autoamputation of digits
Bleeding with minor or no trauma
Easy bleeding
Percent of people who have these symptoms is not available through HPO
Abnormality of metabolism/homeostasis
Laboratory abnormality
Metabolism abnormality

[ more ]

Autosomal dominant inheritance


Support and advocacy groups can help you connect with other patients and families, and they can provide valuable services. Many develop patient-centered information and are the driving force behind research for better treatments and possible cures. They can direct you to research, resources, and services. Many organizations also have experts who serve as medical advisors or provide lists of doctors/clinics. Visit the group’s website or contact them to learn about the services they offer. Inclusion on this list is not an endorsement by GARD.

Organizations Supporting this Disease

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    These resources provide more information about this condition or associated symptoms. The in-depth resources contain medical and scientific language that may be hard to understand. You may want to review these resources with a medical professional.

    Where to Start

    • DermNetNZ provides information on ichthyosis in general. DermNetNZ is an online resource about skin diseases developed by the New Zealand Dermatological Society Incorporated.

      In-Depth Information

      • The Monarch Initiative brings together data about this condition from humans and other species to help physicians and biomedical researchers. Monarch’s tools are designed to make it easier to compare the signs and symptoms (phenotypes) of different diseases and discover common features. This initiative is a collaboration between several academic institutions across the world and is funded by the National Institutes of Health. Visit the website to explore the biology of this condition.
      • Online Mendelian Inheritance in Man (OMIM) is a catalog of human genes and genetic disorders. Each entry has a summary of related medical articles. It is meant for health care professionals and researchers. OMIM is maintained by Johns Hopkins University School of Medicine. 
      • Orphanet is a European reference portal for information on rare diseases and orphan drugs. Access to this database is free of charge.
      • PubMed is a searchable database of medical literature and lists journal articles that discuss Ichthyosis hystrix, Curth Macklin type. Click on the link to view a sample search on this topic.