Rare Oncology News

Disease Profile

Focal dermal hypoplasia

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)



Congenital and Genetic Diseases; Eye diseases; Nervous System Diseases;


Focal dermal hypoplasia is a genetic disorder that primarily affects the skin, skeleton, eyes, and face. The skin abnormalities are present from birth and can include streaks of very thin skin (dermal hypoplasia), cutis aplasia, and telangiectases. They also may abnormalities in the nails, hands, and feet. Some of the eye findings present may include small eyes (microphthalmia), absent or severely underdeveloped eyes (anophthalmia), and problems with the tear ducts. People with focal dermal hypoplasia may also have distinctive facial features such as a pointed chin, small ears, notched nostrils, and a slight difference in the size and shape of the right and left sides of the face (facial asymmetry). Most individuals with this condition are female. Males usually have milder signs and symptoms than females. Although intelligence is typically unaffected, some individuals have intellectual disability. This condition is caused by mutations in the PORCN gene and is inherited in an X-linked dominant manner. Most cases of focal dermal hypoplasia in females result from new mutations in the PORCN gene and occur in people with no history of the disorder in their family. When focal dermal hypoplasia occurs in males, it always results from a new mutation in this gene that is not inherited.[1] Treatment is based on the signs and symptoms present in the person; however, care usually involves a team of specialists, including dermatologists, otolaryngologist, physical/occupational therapists, and hand surgeons.[2]


Focal dermal hypoplasia is usually evident from birth and primarily affects the skin, skeleton, eyes, and face. The signs and symptoms of vary widely, although almost all affected individuals have skin abnormalities.[1]

Some of the skin findings include streaks of very thin skin (dermal hypoplasia), yellowish-pink nodules of fat under the skin, areas where the top layers of skin are absent (cutis aplasia), telangiectases, and streaks of slightly darker or lighter skin. These skin features can cause pain, itching, irritation, or lead to skin infections. With age, most develop wart-like growths, called papillomas, around the nostrils, lips, anus, and female genitalia. They may also be present in the throat, specifically in the esophagus or larynx, and can cause problems with swallowing, breathing, or sleeping. Other features include small, ridged fingernails and toenails as well as sparse, brittle or absent scalp hair.[1]

The skeleton is usually affected as well. Many individuals have hand and foot abnormalities, including missing fingers or toes (oligodactyly), webbed or fused fingers or toes (syndactyly), and a deep split in the hands or feet with missing fingers or toes and fusion of the remaining digits (ectrodactyly). X-rays can show streaks of altered bone density, called osteopathia striata, which usually do not cause symptoms.[1] 

Eye abnormalities are common and can include microphthalmia and anopthalmia as well as problems with the tear ducts. The retina or the optic nerve can also be incompletely developed, which can result in a gap or split in these structures (coloboma). Some of these eye abnormalities do not impair vision, while others can lead to low vision or blindness.[1]

People with focal dermal hypoplasia often have distinctive, but subtle facial features such as a pointed chin, small ears, notched nostrils, and a slight difference in the size and shape of the right and left sides of the face (facial asymmetry). Some individuals may have a cleft lip and/or palate.[1]

About half of those with focal dermal hypoplasia have teeth abnormalities of their teeth, especially of the enamel (the hard, white material that forms the protective outer layer of each tooth). Less commonly, kidney and gastrointestinal abnormalities are present. The kidneys may be fused together, which can lead to kidney infections. The main gastrointestinal abnormality that is seen is an omphalocele.[1]

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
Abnormal palmar dermatoglyphics
Abnormality of dental enamel
Abnormal tooth enamel
Enamel abnormalities
Enamel abnormality

[ more ]

Abnormality of dental morphology
Abnormality of dental shape
Abnormally shaped teeth
Deformity of teeth
Dental deformity
Dental malformations
Malformed teeth
Misshapen teeth
Misshapened teeth

[ more ]

Abnormality of epiphysis morphology
Abnormal shape of end part of bone
Abnormality of skin pigmentation
Abnormal pigmentation
Abnormal skin color
Abnormal skin pigmentation
Abnormality of pigmentation
Pigmentary changes
Pigmentary skin changes
Pigmentation anomaly

[ more ]

Abnormality of the middle ear
Abnormality of the nail
Camptodactyly of finger
Permanent flexion of the finger
Coarse metaphyseal trabecularization
Dermal atrophy
Skin degeneration
Finger syndactyly
Hand polydactyly
Extra finger
Hearing impairment
Hearing defect

[ more ]

Lower limb asymmetry
Left and right leg differ in length or width
Low-set ears
Low set ears
Lowset ears

[ more ]

Flat, discolored area of skin
Reduced number of teeth
Decreased tooth count
Split foot
Lobster-claw foot deformity

[ more ]

Split hand
Claw hand
Claw hand deformities
Claw hands
Claw-hand deformities

[ more ]

Telangiectasia of the skin
Thin skin
Toe syndactyly
Fused toes
Webbed toes

[ more ]

Upper limb asymmetry
Unequal size of arms
30%-79% of people have these symptoms
Hair loss
Chorioretinal coloboma
Birth defect that causes a hole in the innermost layer at the back of the eye
Cognitive impairment
Abnormality of cognition
Cognitive abnormality
Cognitive defects
Cognitive deficits
Intellectual impairment
Mental impairment

[ more ]

Corneal opacity
Diastasis recti
Gap between large left and right abdominal muscles
Ectopia lentis
Facial asymmetry
Asymmetry of face
Crooked face
Unsymmetrical face

[ more ]

Horseshoe kidney
Horseshoe kidneys
Hypoplasia of the iris
Underdeveloped iris
Hypoplastic pelvis
Iris coloboma
Cat eye
Abnormally small eyeball
Multicystic kidney dysplasia
Open bite
Absence of overlap of upper and lower teeth
Open bite between upper and lower teeth

[ more ]

Short clavicles
Short collarbone
Short ribs
Spina bifida
Squint eyes

[ more ]

Subcutaneous nodule
Firm lump under the skin
Growth of abnormal tissue under the skin

[ more ]

5%-29% of people have these symptoms
Abdominal pain
Pain in stomach
Stomach pain

[ more ]

Abnormal adipose tissue morphology
Abnormality of adipose tissue
Abnormality of fat tissue
Abnormality of fatty tissue

[ more ]

Abnormality of the mediastinum
Abnormality of the pulmonary vasculature
Abnormality of the lung blood vessels
Acute hepatic failure
Acute liver failure
Aplasia/Hypoplasia of the lungs
Absent/small lungs
Absent/underdeveloped lungs

[ more ]

Congenital diaphragmatic hernia


Making a diagnosis for a genetic or rare disease can often be challenging. Healthcare professionals typically look at a person’s medical history, symptoms, physical exam, and laboratory test results in order to make a diagnosis. The following resources provide information relating to diagnosis and testing for this condition. If you have questions about getting a diagnosis, you should contact a healthcare professional.

Testing Resources

  • The Genetic Testing Registry (GTR) provides information about the genetic tests for this condition. The intended audience for the GTR is health care providers and researchers. Patients and consumers with specific questions about a genetic test should contact a health care provider or a genetics professional.


    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

      Learn more

      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

      • DermNet NZ is an online resource about skin diseases developed by the New Zealand Dermatological Society Incorporated. DermNet NZ provides information about this condition.
      • Genetics Home Reference (GHR) contains information on Focal dermal hypoplasia. This website is maintained by the National Library of Medicine.
      • The National Organization for Rare Disorders (NORD) has a report for patients and families about this condition. NORD is a patient advocacy organization for individuals with rare diseases and the organizations that serve them.

        In-Depth Information

        • GeneReviews provides current, expert-authored, peer-reviewed, full-text articles describing the application of genetic testing to the diagnosis, management, and genetic counseling of patients with specific inherited conditions.
        • Medscape Reference provides information on this topic. You may need to register to view the medical textbook, but registration is free.
        • 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 Focal dermal hypoplasia. Click on the link to view a sample search on this topic.


          1. Focal dermal hypoplasia. Genetics Home Reference. July 2014; https://ghr.nlm.nih.gov/condition/focal-dermal-hypoplasia.
          2. Sutton, V Reid and Van den Veyver, Ignatia. Focal Dermal Hypoplasia. GeneReviews. April, 2013; https://www.ncbi.nlm.nih.gov/books/NBK1543/. Accessed 1/29/2016.
          3. Focal Dermal Hypoplasia. Genetics Home Reference. July, 2014; https://ghr.nlm.nih.gov/condition/focal-dermal-hypoplasia. Accessed 1/29/2016.

          Rare Oncology News