Overview
Didymosis aplasticosebacea is an extremely rare skin condition that is present from birth. The name comes from the Greek word 'didymos,' meaning twin, because this condition involves the combination of two different types of skin birthmarks (nevi) appearing together on the same person. Specifically, people with this condition have both aplasia cutis congenita (areas where the skin did not fully form, often appearing as patches of missing skin or scarring, usually on the scalp) and nevus sebaceus (yellowish, waxy, slightly raised patches of skin that contain overgrown oil glands, also commonly found on the scalp or face). This condition belongs to a group of disorders called 'twin nevus syndromes' or didymoses, where two different types of skin lesions occur together due to a shared underlying genetic event during early embryonic development. The skin patches of aplasia cutis may look like raw or scarred areas at birth, while the nevus sebaceus patches tend to become more noticeable during puberty as hormones stimulate the oil glands within them. There is no cure for didymosis aplasticosebacea. Treatment is mainly supportive and cosmetic. Small areas of aplasia cutis usually heal on their own, though larger ones may need wound care or surgical repair. Nevus sebaceus patches are often monitored over time because, in rare cases, benign or occasionally malignant tumors can develop within them, particularly in adulthood. Surgical removal of the nevus sebaceus may be recommended for cosmetic reasons or to reduce the small risk of tumor development.
Also known as:
Key symptoms:
Patches of missing or underdeveloped skin at birth, usually on the scalpYellowish, waxy raised skin patches (nevus sebaceus), often on the scalp or faceScarring in areas where skin did not form properlyHairless patches on the scalpSkin patches that become thicker or more noticeable during pubertyPossible development of growths or bumps within the nevus sebaceus over time
Sporadic
Usually appears on its own, not inherited from a parent
Neonatal
Begins at or shortly after birth (first 4 weeks)
Treatments
No FDA-approved treatments are currently listed for Didymosis aplasticosebacea.
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Specialists
View all specialists →No specialists are currently listed for Didymosis aplasticosebacea.
Treatment Centers
8 centersBaylor College of Medicine Rare Disease Center ↗
Baylor College of Medicine
📍 Houston, TX
🏥 NORDStanford Medicine Rare Disease Center ↗
Stanford Medicine
📍 Stanford, CA
🔬 UDNNIH Clinical Center Undiagnosed Diseases Program ↗
National Institutes of Health
📍 Bethesda, MD
🔬 UDNUCLA UDN Clinical Site ↗
UCLA Health
📍 Los Angeles, CA
🔬 UDNBaylor College of Medicine UDN Clinical Site ↗
Baylor College of Medicine
📍 Houston, TX
🔬 UDNHarvard/MGH UDN Clinical Site ↗
Massachusetts General Hospital
📍 Boston, MA
🏥 NORDMayo Clinic Center for Individualized Medicine ↗
Mayo Clinic
📍 Rochester, MN
👤 Mayo Clinic Center for Individualized Medicine
🏥 NORDUCLA Rare Disease Day Program ↗
UCLA Health
📍 Los Angeles, CA
Travel Grants
No travel grants are currently matched to Didymosis aplasticosebacea.
Community
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Caregiver Resources
NORD Caregiver Resources
Support, advocacy, and financial assistance for caregivers of rare disease patients.
Mental Health Support
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Family & Caregiver Grants
Financial assistance programs specifically for caregivers of rare disease patients.
Social Security Disability
Learn how rare disease patients may qualify for SSDI/SSI benefits.
Questions for your doctor
Bring these to your next appointment
- Q1.Should the nevus sebaceus be surgically removed, and if so, when is the best time?,How often should my child have skin checks to monitor for changes in the lesions?,What signs of change in the skin patches should prompt an urgent visit?,Are there any risks of other health problems associated with this condition?,Would genetic testing be helpful for our family, and what would it involve?,What options are available to improve the appearance of scars or hairless patches?,Should my child see a counselor or psychologist to help cope with visible skin differences?
Common questions about Didymosis aplasticosebacea
What is Didymosis aplasticosebacea?
Didymosis aplasticosebacea is an extremely rare skin condition that is present from birth. The name comes from the Greek word 'didymos,' meaning twin, because this condition involves the combination of two different types of skin birthmarks (nevi) appearing together on the same person. Specifically, people with this condition have both aplasia cutis congenita (areas where the skin did not fully form, often appearing as patches of missing skin or scarring, usually on the scalp) and nevus sebaceus (yellowish, waxy, slightly raised patches of skin that contain overgrown oil glands, also commonly
How is Didymosis aplasticosebacea inherited?
Didymosis aplasticosebacea follows a sporadic inheritance pattern. Genetic counseling can help families understand recurrence risk and testing options.
At what age does Didymosis aplasticosebacea typically begin?
Typical onset of Didymosis aplasticosebacea is neonatal. Age of onset can vary across affected individuals.